Coronavirus cases are once again increasing in the UK, and several patients have reported getting infected for the second or third time. This has led experts to believe that people are bound to get re-infected every 16 months of they are not fully vaccinated.<o:p></o:p>

A new analysis has suggested that people who have chosen not to get vaccinated against the deadly coronavirus can keep getting re-infected with the disease every 16 months.<o:p></o:p>

Last year, it was observed that people were getting infected by the virus for second time. However, till then vaccinations had not started at such a large scale. Now, that vaccination programmes have started around the world, scientists have been able to study the comparative data.

<o:p>Also read |&nbsp;<a href="https://www.wionews.com/world/bring-back-covid-regulations-urge-health-experts-as-cases-in-uk-rise-again-422313">'Bring back Covid regulations', urge health experts as cases in UK rise again</a></o:p>

As per the data, experts have been able to see that people who have not been fully vaccinated against <a href="https://www.wionews.com/topics/coronavirus">coronavirus</a> are the ones who are getting re-infected. <o:p></o:p>

However, experts believe that it is not just once or twice that the re-infection can happen. Unvaccinated people are expected to get re-infected after every 16 years, on an average.<o:p></o:p>

This is especially relevant for people who work in areas where they spend majority time in interacting with other people. People working in hospitals, schools etc are more exposed to the virus.<o:p></o:p>

"If you've got high-level prevalence, and frequent exposure to the virus, as you have in schools, you are going to see more and more people getting reinfected despite having been double vaccinated," said Stephen Griffin, associate professor of virology at the University of Leeds told the Guardian.<o:p></o:p>

This has become more common and dangerous since the Delta variant started surfacing in countries all around the world. The Delta variant is one of the deadliest and most transmissible variants of coronavirus till now. The reinfection rate has also increased around the world since the cases of Delta variant surged.<o:p></o:p>

Coronavirus cases are once again increasing in the UK, and several patients have reported getting infected for the second or third time. This has led experts to believe that people are bound to get re-infected every 16 months of they are not fully vaccinated.

Coronavirus cases are once again increasing in the UK, and several patients have reported getting infected for the second or third time. This has led experts to believe that people are bound to get re-infected every 16 months of they are not fully vaccinated. A new analysis has suggested that people who have chosen not to get vaccinated against the deadly coronavirus can keep getting re-infected with the disease every 16 months. Last year, it was observed that people were getting infected by the virus for second time. However, till then vaccinations had not started at such a large scale. Now, that vaccination programmes have started around the world, scientists have been able to study the comparative data. Also read | 'Bring back Covid regulations', urge health experts as cases in UK rise again As per the data, experts have been able to see that people who have not been fully vaccinated against coronavirus are the ones who are getting re-infected. However, experts believe that it is not just once or twice that the re-infection can happen. Unvaccinated people are expected to get re-infected after every 16 years, on an average. This is especially relevant for people who work in areas where they spend majority time in interacting with other people. People working in hospitals, schools etc are more exposed to the virus. "If you've got high-level prevalence, and frequent exposure to the virus, as you have in schools, you are going to see more and more people getting reinfected despite having been double vaccinated," said Stephen Griffin, associate professor of virology at the University of Leeds told the Guardian. This has become more common and dangerous since the Delta variant started surfacing in countries all around the world. The Delta variant is one of the deadliest and most transmissible variants of coronavirus till now. The reinfection rate has also increased around the world since the cases of Delta variant surged.

Unvaccinated people can get infected by coronavirus every 16 months: Experts

People who have been infected with novel coronavirus are as protected against reinfection as those who have received COVID-19 vaccines, according to the latest study.

Preliminary findings by scientists at Public Health England (PHE) showed that reinfections in people who have COVID-19 antibodies from a past infection are rare,&nbsp;with only 44 cases found among 6,614 previously infected people in the study.

But experts cautioned that the findings mean people who contracted the disease in the first wave of the pandemic in the early months of 2020 may now be vulnerable to catching it again.

They also warned that people with so-called "natural&nbsp;immunity",&nbsp;acquired through having had the infection - may still be able to carry the SARS-CoV-2 coronavirus in their nose and throat, and could unwittingly pass it on.

“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts," said Susan Hopkins, senior medical adviser at PHE and co-leader of the study, whose findings were published on Thursday.

“This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections. But there is still a risk you could acquire an infection and transmit (it) to others."

A statement on the study said its findings did not address antibody or other immune responses to vaccines now being rolled out against COVID-19, or on how effective vaccines would be. Vaccine responses will be considered later this year, it said.

The research, known as the SIREN study, involves tens of thousands of healthcare workers in Britain who have been tested regularly since June for new COVID-19 infections as well as for the presence of antibodies.

Between June 18 and November&nbsp;24 scientists detected 44 potential reinfections,&nbsp;two "probable" and 42 "possible" - out of 6,614 participants who had tested positive for antibodies. This represents an 83 per cent&nbsp;rate of protection from reinfection, they said.

The researchers plan to continue following and assessing the participants to see if this natural&nbsp;immunity&nbsp;might last longer than five months in some. But they warned that early evidence from the next stage of the study already suggests some people with&nbsp;immunity&nbsp;can still carry high levels of virus and could transmit it to others.

"It is, therefore, crucial that everyone continues to follow the rules and stays at home, even if they have previously had COVID-19," they said in the statement about their results.

People who have been infected with novel coronavirus are as protected against reinfection as those who have received COVID-19 vaccines, according to the latest study.

People who have been infected with novel coronavirus are as protected against reinfection as those who have received COVID-19 vaccines, according to the latest study. Preliminary findings by scientists at Public Health England (PHE) showed that reinfections in people who have COVID-19 antibodies from a past infection are rare, with only 44 cases found among 6,614 previously infected people in the study. But experts cautioned that the findings mean people who contracted the disease in the first wave of the pandemic in the early months of 2020 may now be vulnerable to catching it again. They also warned that people with so-called "natural immunity", acquired through having had the infection - may still be able to carry the SARS-CoV-2 coronavirus in their nose and throat, and could unwittingly pass it on. “We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts," said Susan Hopkins, senior medical adviser at PHE and co-leader of the study, whose findings were published on Thursday. “This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections. But there is still a risk you could acquire an infection and transmit (it) to others." A statement on the study said its findings did not address antibody or other immune responses to vaccines now being rolled out against COVID-19, or on how effective vaccines would be. Vaccine responses will be considered later this year, it said. The research, known as the SIREN study, involves tens of thousands of healthcare workers in Britain who have been tested regularly since June for new COVID-19 infections as well as for the presence of antibodies. Between June 18 and November 24 scientists detected 44 potential reinfections, two "probable" and 42 "possible" - out of 6,614 participants who had tested positive for antibodies. This represents an 83 per cent rate of protection from reinfection, they said. The researchers plan to continue following and assessing the participants to see if this natural immunity might last longer than five months in some. But they warned that early evidence from the next stage of the study already suggests some people with immunity can still carry high levels of virus and could transmit it to others. "It is, therefore, crucial that everyone continues to follow the rules and stays at home, even if they have previously had COVID-19," they said in the statement about their results.

Coronavirus infection provides as much immunity as vaccines: Study

COVID-19 survivors may have protective immunity against serious disease from the SARS-CoV-2 virus for months, or even years after the infection, a study suggests.

The findings, based on analyses of blood samples from 188 COVID-19 patients, suggest that nearly all survivors of the disease have the immune cells necessary to fight re-infection.

Also read | <a href="https://www.wionews.com/world/portuguese-nurse-dies-two-days-after-getting-the-pfizer-covid-vaccine-354526">Portuguese nurse dies two days after getting the Pfizer Covid vaccine</a>

"Our data suggest that the immune response is there -- and it stays," Professor Alessandro Sette from La Jolla Institute for Immunology in the US.

The researchers measured antibodies, memory B cells, helper T cells and killer T cells -- all four components of immune memory -- at the same time.

The study, published in the journal Science, helps clarify some concerning data from other institutes, which showed a dramatic drop-off of COVID-fighting antibodies in the months following infection.

Some feared that this decline in antibodies meant that the body wouldn't be equipped to defend itself against reinfection.

Sette explained that a decline in antibodies is very normal.

"Of course, the immune response decreases over time to a certain extent, but that's normal," he noted.

"That's what immune responses do. They have a first phase of ramping up, and after that fantastic expansion, eventually the immune response contracts somewhat and gets to a steady state," Sette added.

The researchers found that virus-specific antibodies do persist in the bloodstream months after infection.

They said the body also has immune cells called memory B cells at the ready, adding that if a person encounters SARS-CoV-2 again, these cells could reactivate and produce antibodies to fight re-infection.

The SARS-CoV-2 virus uses its "spike" protein to initiate infection of human cells, so the researchers looked for memory B cells specific for the SARS-CoV-2 spike.

They found that spike-specific memory B cells actually increased in the blood six months after infection.

"COVID-19 survivors also had an army of T cells ready to fight reinfection. Memory CD4+ "helper" T cells lingered, ready to trigger an immune response if they saw SARS-CoV-2 again," the researchers said.

Many memory CB8+ "killer" T cells also remained, ready to destroy infected cells and halt a reinfection, they said.

"The different parts of the adaptive immune systems work together, so seeing COVID-fighting antibodies, memory B cells, memory CD4+ T cells and memory CD8+ T cells in the blood more than eight months following infection is a good sign," said LJI Professor Shane Crotty.

"This implies that there's a good chance people would have protective immunity, at least against serious disease, for that period of time, and probably well beyond that," Crotty said.

However, the researchers cautioned that protective immunity does vary dramatically from person to person.

They saw a 100-fold range in the magnitude of immune memory.

"People with a weak immune memory may be vulnerable to a case of recurrent COVID-19 in the future, or they may be more likely to infect others," the researchers said.&nbsp;

COVID-19 survivors may have protective immunity against serious disease from the SARS-CoV-2 virus for months, or even years after the infection, a study suggests.

COVID-19 survivors may have protective immunity against serious disease from the SARS-CoV-2 virus for months, or even years after the infection, a study suggests. The findings, based on analyses of blood samples from 188 COVID-19 patients, suggest that nearly all survivors of the disease have the immune cells necessary to fight re-infection. Also read | Portuguese nurse dies two days after getting the Pfizer Covid vaccine "Our data suggest that the immune response is there -- and it stays," Professor Alessandro Sette from La Jolla Institute for Immunology in the US. The researchers measured antibodies, memory B cells, helper T cells and killer T cells -- all four components of immune memory -- at the same time. The study, published in the journal Science, helps clarify some concerning data from other institutes, which showed a dramatic drop-off of COVID-fighting antibodies in the months following infection. Some feared that this decline in antibodies meant that the body wouldn't be equipped to defend itself against reinfection. Sette explained that a decline in antibodies is very normal. "Of course, the immune response decreases over time to a certain extent, but that's normal," he noted. "That's what immune responses do. They have a first phase of ramping up, and after that fantastic expansion, eventually the immune response contracts somewhat and gets to a steady state," Sette added. The researchers found that virus-specific antibodies do persist in the bloodstream months after infection. They said the body also has immune cells called memory B cells at the ready, adding that if a person encounters SARS-CoV-2 again, these cells could reactivate and produce antibodies to fight re-infection. The SARS-CoV-2 virus uses its "spike" protein to initiate infection of human cells, so the researchers looked for memory B cells specific for the SARS-CoV-2 spike. They found that spike-specific memory B cells actually increased in the blood six months after infection. "COVID-19 survivors also had an army of T cells ready to fight reinfection. Memory CD4+ "helper" T cells lingered, ready to trigger an immune response if they saw SARS-CoV-2 again," the researchers said. Many memory CB8+ "killer" T cells also remained, ready to destroy infected cells and halt a reinfection, they said. "The different parts of the adaptive immune systems work together, so seeing COVID-fighting antibodies, memory B cells, memory CD4+ T cells and memory CD8+ T cells in the blood more than eight months following infection is a good sign," said LJI Professor Shane Crotty. "This implies that there's a good chance people would have protective immunity, at least against serious disease, for that period of time, and probably well beyond that," Crotty said. However, the researchers cautioned that protective immunity does vary dramatically from person to person. They saw a 100-fold range in the magnitude of immune memory. "People with a weak immune memory may be vulnerable to a case of recurrent COVID-19 in the future, or they may be more likely to infect others," the researchers said.

Protective immunity against novel coronavirus may last for over eight months: Study

China’s President Xi Jinping violently coughs throughout a speech to Communist party faithful in Shenzhen, prompting speculation on his health, as state media cuts away each time he is forced to stop speaking.

Cameras cut away from the President but he was heard spluttering on audio. Episode promoted his critics to speculate whether he has coronavirus. 
 
Watch | Gravitas: Xi Jinping struggles through speech, coughs multiple times

<div class="videoWrapper trancodeVideo"><iframe allowfullscreen="" autoplay="1" class="includeVideo" frameborder="0" height="350" src="https://www.wionews.com/videos/gravitas-xi-jinping-struggles-through-speech-coughs-multiple-times-335588/embed" style="width:100%;max-width:560px;" width="560"></iframe></div>

Hong Kong's Apple Daily, which ran the headline "Xi Jinping coughs and coughs at Shenzhen event as Carrie Lam stays away from VIPs," noted that the Chinese president "was seen coughing away and drinking water."

Beijing should come clean even if the president has a condition. Speaking out might improve their image and he won't be the only one to have tested positive, if he has.

Leaders are not immune to coughs or to the Wuhan virus.US president Donald Trump tested positive. So did Boris Johnson of the United Kingdom and Jair Bolsonaro of Brazil.

The presidents of Bolivia, Guatemala and Honduras - were infected too. As were the prime ministers of Armenia and Russia. Xi Jinping would be just another name on the list.

But he won't be, China isn't famous for being transparent. Xi had also mysteriously disappeared when the virus first spread. He went missing from public view not once, but twice.

Then he appeared without a mask. In a bid to prove that China has defeated the virus. He lifted lockdowns and allowed pool parties. The stunt may have backfired. He sat coughing with China's top leaders in close proximity.

He may have compromised all of them. Trump would have been hauled over the coals for something like this. But in China, nobody questions the president. Everyone says the virus has been defeated.

Worldwide there's a looming second wave another round of lockdowns.

But China is immune from its own virus. China will also keep injecting its citizens with dubious vaccines and keep lifting restrictions as if the virus has vanished.&nbsp; 
 
Govt backed state media has issued so many propaganda videos to show that China has bounced back. But&nbsp;one man's cough can undo a lot.

(With inputs from agencies)

China’s President Xi Jinping violently coughs throughout a speech to Communist party faithful in Shenzhen, prompting speculation on his health, as state media cuts away each time he is forced to stop speaking.

China’s President Xi Jinping violently coughs throughout a speech to Communist party faithful in Shenzhen, prompting speculation on his health, as state media cuts away each time he is forced to stop speaking. Cameras cut away from the President but he was heard spluttering on audio. Episode promoted his critics to speculate whether he has coronavirus. Watch | Gravitas: Xi Jinping struggles through speech, coughs multiple times Hong Kong's Apple Daily, which ran the headline "Xi Jinping coughs and coughs at Shenzhen event as Carrie Lam stays away from VIPs," noted that the Chinese president "was seen coughing away and drinking water." Beijing should come clean even if the president has a condition. Speaking out might improve their image and he won't be the only one to have tested positive, if he has. Leaders are not immune to coughs or to the Wuhan virus.US president Donald Trump tested positive. So did Boris Johnson of the United Kingdom and Jair Bolsonaro of Brazil. The presidents of Bolivia, Guatemala and Honduras - were infected too. As were the prime ministers of Armenia and Russia. Xi Jinping would be just another name on the list. But he won't be, China isn't famous for being transparent. Xi had also mysteriously disappeared when the virus first spread. He went missing from public view not once, but twice. Then he appeared without a mask. In a bid to prove that China has defeated the virus. He lifted lockdowns and allowed pool parties. The stunt may have backfired. He sat coughing with China's top leaders in close proximity. He may have compromised all of them. Trump would have been hauled over the coals for something like this. But in China, nobody questions the president. Everyone says the virus has been defeated. Worldwide there's a looming second wave another round of lockdowns. But China is immune from its own virus. China will also keep injecting its citizens with dubious vaccines and keep lifting restrictions as if the virus has vanished. Govt backed state media has issued so many propaganda videos to show that China has bounced back. But one man's cough can undo a lot. (With inputs from agencies)

Xi Jinping coughs 'violently' during key speech, sparking health fears

Reports of reinfection with the coronavirus evoke a nightmarish future: Repeat bouts of illness, impotent vaccines, unrelenting lockdowns — a pandemic without an end.

A case study published Monday, about a 25-year-old man in Nevada, has stoked those fears anew. The man, who was not named, became sicker the second time that he was infected with the virus, a pattern the immune system is supposed to prevent.

But these cases make the news precisely because they are rare, experts said: More than 38 million people worldwide have been infected with the coronavirus, and as of Monday, fewer than five of those cases have been confirmed by scientists to be reinfections.

“That’s tiny — it’s like a microliter-sized drop in the bucket, compared to the number of cases that have happened all over the world,” said Angela Rasmussen, a virologist at Columbia University in New York.

In most cases, a second bout with the virus produced milder symptoms or none at all. But for at least three people, including one patient in Ecuador, the illness was more severe the second time around than during the first infection. An 89-year-old woman in the Netherlands died during her second illness.

Rare as these cases may be, they do indicate that reinfection is possible, said Akiko Iwasaki, an immunologist at Yale University, who wrote a commentary accompanying the Nevada case study, published in The Lancet Infectious Diseases.

“It’s important to note that there are people who do get reinfected, and in some of those cases you get worse disease,” Iwasaki said. “You still need to keep wearing masks and practice social distancing even if you have recovered once from this infection.”

We asked experts what is known about reinfections with the coronavirus, and what the phenomenon means for vaccinations and the course of the pandemic.

Reinfection with the coronavirus is an unusual event.

First, the good news: Reinfection seems to be vanishingly rare.

Since the first confirmed case of reinfection, reported in Hong Kong on Aug. 24, there have been three published cases; reports of another 20 await scientific review.

But it is impossible to know exactly how widespread the phenomenon is. To confirm a case of reinfection, scientists must look for significant differences in the genes of the two coronaviruses causing both illnesses.

In the United States, where testing was a rare resource much of this year, many people were not tested unless they were sick enough to be hospitalized. Even then, their samples were usually not preserved for genetic analysis, making it impossible to confirm suspected reinfections.

A vast majority of people who do get reinfected may go undetected. For example, the man in Hong Kong had no symptoms the second time, and his infection was discovered only because of routine screening at the airport.

“There are a lot of people that are going to also have been exposed that aren’t having symptoms, that we’re never going to hear about,” said Marion Pepper, an immunologist at the University of Washington in Seattle.

People whose second infections are more severe are more likely to be identified, because they return to the hospital. But those are likely to be even rarer, experts said.

“If this was a very common event, we would have seen thousands of cases,” Iwasaki said.

In most people, the immune system works as expected.

Reinfections can occur for any number of reasons: because the initial infection was too mild to produce an immune response, for example, or because the immune system was compromised by other health conditions. On occasion, a patient may be exposed to a large amount of virus that seeded an infection before the immune response could respond.

This variability is entirely expected, experts said, and has been observed in patients with diseases like measles and malaria.

“You’ll never have the distribution of anything with millions of people where you don’t have some very severe rare cases happening at the fringe,” said Dr. Michael Mina, a pediatric immunologist at the Harvard T.H. Chan School of Public Health.

At least two of the reinfected patients in Europe had compromised immune systems, for example, and the 89-year-old woman who died was receiving chemotherapy. In other reinfected patients, genetic factors or the lack of certain previous immune exposures may have blunted the body’s ability to fight off a second attack.

“There are some people who just don’t develop good immune responses to certain pathogens,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai. “What is causing that? We’re not sure, but it’s rare, usually.”

In a vast majority of known infected patients, experts said, the immune system functions as it should against other pathogens.

“There are a lot of different infections where you can get reexposed to the virus, and we would probably not know because you don’t have symptoms,” Pepper said. “And that might be an important part of boosting immunity.”

When the body is exposed to an unfamiliar virus, it is normal first to develop some immunity and then to increase that response with each additional exposure. This phenomenon is well known among children, but it is less often seen in adults because they rarely encounter new viruses, Mina said.

“I think it’s important to recognize that reinfections are literally embedded in the evolution of our immune system,” he added. “We sometimes lose track of that with so many people talking about this who really haven’t studied the immune system.”

A resurgence of symptoms doesn’t prove reinfection.

For every confirmed case of reinfection, there are dozens of anecdotal reports of infected people who were sick and seemingly recovered but then became ill again weeks to months later.

Usually there are crucial data missing in those cases, like a confirmed lab diagnosis, or a virus sample that can be sequenced.

“The question is always, Is it a real reinfection?” Krammer said. “It’s very often very challenging to kind of get that kind of data.”

A vast majority of these cases are unlikely to be true infections. More likely, these are people experiencing a resurgence of symptoms connected to the original infection. The virus may set off an inflammatory response that can flare up even weeks later and cause symptoms like fatigue and heart problems. In rare cases, some patients may develop a chronic low-grade infection with the virus that never quite goes away.

“Even with viruses that can cause acute infections, like flu,” Krammer said, “you can have persistent infections if your immune system is sufficiently compromised.”

Although these are not real reinfections, they are still worrying if they lead to renewed illness or hospitalization months after the initial infection, Rasmussen said. “If there’s recrudescence happening frequently, and people are getting severely ill the second time around, that’s potentially its own problem,” she said.

People with a second bout may pass the virus to others.

Reinfected people without symptoms may still transmit the virus to others. The patient in Hong Kong, for example, was isolated in a hospital even though he had no symptoms. But his viral load was high enough that he could have passed the virus to others.

“Obviously, that person wasn’t ill, so it bodes well for him, but it doesn’t bode well for the community,” Pepper said.

But to be sure of infectiousness, researchers may need to look for live virus. South Korean researchers investigated hundreds of reports of reinfection and were able to rule them out as real cases after failing to grow infectious virus from the samples.

Similar procedures would be needed to rule out the possibility of transmission in each patient, Rasmussen said, adding, “I think that’s the only way you’d be able to get to the bottom of that.”

Reports of reinfection with the coronavirus evoke a nightmarish future: Repeat bouts of illness, impotent vaccines, unrelenting lockdowns — a pandemic without an end.

Reports of reinfection with the coronavirus evoke a nightmarish future: Repeat bouts of illness, impotent vaccines, unrelenting lockdowns — a pandemic without an end. A case study published Monday, about a 25-year-old man in Nevada, has stoked those fears anew. The man, who was not named, became sicker the second time that he was infected with the virus, a pattern the immune system is supposed to prevent. But these cases make the news precisely because they are rare, experts said: More than 38 million people worldwide have been infected with the coronavirus, and as of Monday, fewer than five of those cases have been confirmed by scientists to be reinfections. “That’s tiny — it’s like a microliter-sized drop in the bucket, compared to the number of cases that have happened all over the world,” said Angela Rasmussen, a virologist at Columbia University in New York. In most cases, a second bout with the virus produced milder symptoms or none at all. But for at least three people, including one patient in Ecuador, the illness was more severe the second time around than during the first infection. An 89-year-old woman in the Netherlands died during her second illness. Rare as these cases may be, they do indicate that reinfection is possible, said Akiko Iwasaki, an immunologist at Yale University, who wrote a commentary accompanying the Nevada case study, published in The Lancet Infectious Diseases. “It’s important to note that there are people who do get reinfected, and in some of those cases you get worse disease,” Iwasaki said. “You still need to keep wearing masks and practice social distancing even if you have recovered once from this infection.” We asked experts what is known about reinfections with the coronavirus, and what the phenomenon means for vaccinations and the course of the pandemic. Reinfection with the coronavirus is an unusual event. First, the good news: Reinfection seems to be vanishingly rare. Since the first confirmed case of reinfection, reported in Hong Kong on Aug. 24, there have been three published cases; reports of another 20 await scientific review. But it is impossible to know exactly how widespread the phenomenon is. To confirm a case of reinfection, scientists must look for significant differences in the genes of the two coronaviruses causing both illnesses. In the United States, where testing was a rare resource much of this year, many people were not tested unless they were sick enough to be hospitalized. Even then, their samples were usually not preserved for genetic analysis, making it impossible to confirm suspected reinfections. A vast majority of people who do get reinfected may go undetected. For example, the man in Hong Kong had no symptoms the second time, and his infection was discovered only because of routine screening at the airport. “There are a lot of people that are going to also have been exposed that aren’t having symptoms, that we’re never going to hear about,” said Marion Pepper, an immunologist at the University of Washington in Seattle. People whose second infections are more severe are more likely to be identified, because they return to the hospital. But those are likely to be even rarer, experts said. “If this was a very common event, we would have seen thousands of cases,” Iwasaki said. In most people, the immune system works as expected. Reinfections can occur for any number of reasons: because the initial infection was too mild to produce an immune response, for example, or because the immune system was compromised by other health conditions. On occasion, a patient may be exposed to a large amount of virus that seeded an infection before the immune response could respond. This variability is entirely expected, experts said, and has been observed in patients with diseases like measles and malaria. “You’ll never have the distribution of anything with millions of people where you don’t have some very severe rare cases happening at the fringe,” said Dr. Michael Mina, a pediatric immunologist at the Harvard T.H. Chan School of Public Health. At least two of the reinfected patients in Europe had compromised immune systems, for example, and the 89-year-old woman who died was receiving chemotherapy. In other reinfected patients, genetic factors or the lack of certain previous immune exposures may have blunted the body’s ability to fight off a second attack. “There are some people who just don’t develop good immune responses to certain pathogens,” said Florian Krammer, an immunologist at the Icahn School of Medicine at Mount Sinai. “What is causing that? We’re not sure, but it’s rare, usually.” In a vast majority of known infected patients, experts said, the immune system functions as it should against other pathogens. “There are a lot of different infections where you can get reexposed to the virus, and we would probably not know because you don’t have symptoms,” Pepper said. “And that might be an important part of boosting immunity.” When the body is exposed to an unfamiliar virus, it is normal first to develop some immunity and then to increase that response with each additional exposure. This phenomenon is well known among children, but it is less often seen in adults because they rarely encounter new viruses, Mina said. “I think it’s important to recognize that reinfections are literally embedded in the evolution of our immune system,” he added. “We sometimes lose track of that with so many people talking about this who really haven’t studied the immune system.” A resurgence of symptoms doesn’t prove reinfection. For every confirmed case of reinfection, there are dozens of anecdotal reports of infected people who were sick and seemingly recovered but then became ill again weeks to months later. Usually there are crucial data missing in those cases, like a confirmed lab diagnosis, or a virus sample that can be sequenced. “The question is always, Is it a real reinfection?” Krammer said. “It’s very often very challenging to kind of get that kind of data.” A vast majority of these cases are unlikely to be true infections. More likely, these are people experiencing a resurgence of symptoms connected to the original infection. The virus may set off an inflammatory response that can flare up even weeks later and cause symptoms like fatigue and heart problems. In rare cases, some patients may develop a chronic low-grade infection with the virus that never quite goes away. “Even with viruses that can cause acute infections, like flu,” Krammer said, “you can have persistent infections if your immune system is sufficiently compromised.” Although these are not real reinfections, they are still worrying if they lead to renewed illness or hospitalization months after the initial infection, Rasmussen said. “If there’s recrudescence happening frequently, and people are getting severely ill the second time around, that’s potentially its own problem,” she said. People with a second bout may pass the virus to others. Reinfected people without symptoms may still transmit the virus to others. The patient in Hong Kong, for example, was isolated in a hospital even though he had no symptoms. But his viral load was high enough that he could have passed the virus to others. “Obviously, that person wasn’t ill, so it bodes well for him, but it doesn’t bode well for the community,” Pepper said. But to be sure of infectiousness, researchers may need to look for live virus. South Korean researchers investigated hundreds of reports of reinfection and were able to rule them out as real cases after failing to grow infectious virus from the samples. Similar procedures would be needed to rule out the possibility of transmission in each patient, Rasmussen said, adding, “I think that’s the only way you’d be able to get to the bottom of that.”

Coronavirus reinfections are real but very, very rare

A 25-year-old Reno man with mild COVID-19 symptoms initially was found to have the virus in April. He recovered and tested negative twice, and then tested positive again in June. He was much sicker the second time, with pneumonia that required hospitalisation and oxygen treatment.

US: Nevada man infected twice with COVID-19, HK researchers confirmed similar case

Researchers at the University of Hong Kong (HKU) said that they had confirmed the world's "first case" of coronavirus reinfection after a 33-year-old man got the infection once again after over four months.

<a href="https://www.wionews.com/world/south-korea-orders-schools-to-be-shut-in-seoul-amid-surge-in-virus-cases-322891">Also Read:&nbsp;South Korea orders schools to be shut in Seoul amid surge in virus cases</a>

The man's two viral signatures were "completely different", and belonged to different coronavirus lineages, according to researchers after he suffered a relapse. The researchers found that first strain resembled those that were collected in March and April, however, the second strain matched the virus found in Europe after the person visited the continent in July and August.&nbsp;

The man had travalled to Spain and had returned to Hong Kong via London after he was detected with the virus during screening at the airport. The man's PCR swab test was positive.

"Our study proves that immunity for COVID infection is not lifelong, in fact, reinfection can occur quite quickly," Kelvin Kai-Wang To, microbiologist and lead author of the study, said.

Although there have been cases reported of reinfections, however, this is the first time it has been proven after tests. “This is the world’s first documentation of a patient who recovered from COVID-19 but got another episode of COVID-19 afterwards,” the researchers said in a statement.

However, the World Health Organization(WHO) said it needs to look at the case at the "at a population level” as there have been "24 million cases reported to date".

"The finding does not mean taking vaccines will be useless," Dr. Kai-Wang To said, adding,"immunity induced by vaccination can be different from those induced by natural infection," To said. "[We] will need to wait for the results of the vaccine trials to see if how effective vaccines are."

Worrying news emerged from Belgium and Netherlands on Tuesday as Dutch media reported re-infections of coronavirus. A patient in the Netherlands and another in Belgium got infected after making recovery from Covid-19 infection the first time around. The development on Tuesday follows reports of the first known re-infection of coronavirus in Hong Kong. This has been confirmed by scientists.

Dutch broadcaster NOS reported that the re-infected patient in the Netherlands was an old person with a weakened immune system.

Virologist Marion Koopmans, cited by the NOS, said that it was common for people to remain infected with the virus for a long time with mild symptoms. The infection flares up in some cases. Marion Koopmans said that genetic testing was required in both instances of infection to check whether there were any differences in the virus present.

Researchers at the University of Hong Kong (HKU) said that they had confirmed the world's "first case" of coronavirus reinfection after a 33-year-old man got the infection once again after over four months.

Researchers at the University of Hong Kong (HKU) said that they had confirmed the world's "first case" of coronavirus reinfection after a 33-year-old man got the infection once again after over four months. Also Read: South Korea orders schools to be shut in Seoul amid surge in virus cases The man's two viral signatures were "completely different", and belonged to different coronavirus lineages, according to researchers after he suffered a relapse. The researchers found that first strain resembled those that were collected in March and April, however, the second strain matched the virus found in Europe after the person visited the continent in July and August. The man had travalled to Spain and had returned to Hong Kong via London after he was detected with the virus during screening at the airport. The man's PCR swab test was positive. "Our study proves that immunity for COVID infection is not lifelong, in fact, reinfection can occur quite quickly," Kelvin Kai-Wang To, microbiologist and lead author of the study, said. Although there have been cases reported of reinfections, however, this is the first time it has been proven after tests. “This is the world’s first documentation of a patient who recovered from COVID-19 but got another episode of COVID-19 afterwards,” the researchers said in a statement. However, the World Health Organization(WHO) said it needs to look at the case at the "at a population level” as there have been "24 million cases reported to date". "The finding does not mean taking vaccines will be useless," Dr. Kai-Wang To said, adding,"immunity induced by vaccination can be different from those induced by natural infection," To said. "[We] will need to wait for the results of the vaccine trials to see if how effective vaccines are." Worrying news emerged from Belgium and Netherlands on Tuesday as Dutch media reported re-infections of coronavirus. A patient in the Netherlands and another in Belgium got infected after making recovery from Covid-19 infection the first time around. The development on Tuesday follows reports of the first known re-infection of coronavirus in Hong Kong. This has been confirmed by scientists. Dutch broadcaster NOS reported that the re-infected patient in the Netherlands was an old person with a weakened immune system. Virologist Marion Koopmans, cited by the NOS, said that it was common for people to remain infected with the virus for a long time with mild symptoms. The infection flares up in some cases. Marion Koopmans said that genetic testing was required in both instances of infection to check whether there were any differences in the virus present.

World’s 'first' coronavirus reinfection case confirmed in Hong Kong

Worrying news emerged from Belgium and Netherlands on Tuesday as Dutch media reported re-infections of coronavirus. A patient in the Netherlands and another in Belgium got infected after making recovery from Covid-19 infection the first time around. The development on Tuesday follows reports of the first known re-infection of coronavirus in Hong Kong. This has been confirmed by scientists. 
 
<a href="https://www.wionews.com/world/worlds-first-coronavirus-reinfection-case-confirmed-in-hong-kong-322896">Also read | World’s 'first' coronavirus reinfection case confirmed in Hong Kong</a>

Dutch broadcaster NOS reported that the re-infected patient in the Netherlands was an old person with a weakened immune system.

Virologist Marion Koopmans, cited by the NOS, said that it was common for people to remain infected with the virus for a long time with mild symptoms. The infection flares up in some cases. Marion Koopmans said that genetic testing was required in both instances of infection to check whether there were any differences in the virus present.

"Not good News"

Virologist Marc Van Ranst told Dutch media that antibodies developed by the Belgian patient were not strong enough to fend off slightly different variant of the virus.

"It's not good news," Ranst was quoted as saying by NOS.

It is not yet clear whether the cases were one-off or there was a danger of a large number of people getting re-infected after they recovered from Covid-19.

Situation in Hong Kong:

On Monday, a man in Hong Kong was found to have been reinfected by coronavirus after a trip to Spain. He was infected in March and caught the virus again after his trip in mid-August.

Experts are warning the public to not let the guard down after recovery from the infection as the cases mentioned above show that some people did not have lifelong immunity against coronavirus.

Some experts however see a silver-lining. They say that re-infections were a sign of 'residual immunity' in the patient.

So what about the vaccine?

There is an ongoing global race to create coronavirus vaccine. While concerns remain about reinfection adding another element to the fray, some scientists are not willing to take 'rare examples' as something that derails the process of making a coronavirus vaccine.

Worrying news emerged from Belgium and Netherlands on Tuesday as Dutch media reported re-infections of coronavirus. A patient in the Netherlands and another in Belgium got infected after making recovery from Covid-19 infection the first time around.

Worrying news emerged from Belgium and Netherlands on Tuesday as Dutch media reported re-infections of coronavirus. A patient in the Netherlands and another in Belgium got infected after making recovery from Covid-19 infection the first time around. The development on Tuesday follows reports of the first known re-infection of coronavirus in Hong Kong. This has been confirmed by scientists. Also read | World’s 'first' coronavirus reinfection case confirmed in Hong Kong Dutch broadcaster NOS reported that the re-infected patient in the Netherlands was an old person with a weakened immune system. Virologist Marion Koopmans, cited by the NOS, said that it was common for people to remain infected with the virus for a long time with mild symptoms. The infection flares up in some cases. Marion Koopmans said that genetic testing was required in both instances of infection to check whether there were any differences in the virus present. "Not good News" Virologist Marc Van Ranst told Dutch media that antibodies developed by the Belgian patient were not strong enough to fend off slightly different variant of the virus. "It's not good news," Ranst was quoted as saying by NOS. It is not yet clear whether the cases were one-off or there was a danger of a large number of people getting re-infected after they recovered from Covid-19. Situation in Hong Kong: On Monday, a man in Hong Kong was found to have been reinfected by coronavirus after a trip to Spain. He was infected in March and caught the virus again after his trip in mid-August. Experts are warning the public to not let the guard down after recovery from the infection as the cases mentioned above show that some people did not have lifelong immunity against coronavirus. Some experts however see a silver-lining. They say that re-infections were a sign of 'residual immunity' in the patient. So what about the vaccine? There is an ongoing global race to create coronavirus vaccine. While concerns remain about reinfection adding another element to the fray, some scientists are not willing to take 'rare examples' as something that derails the process of making a coronavirus vaccine.

Second wave of Covid-19? Re-infections in Belgium and the Netherlands make experts wary

The COVID-19 pandemic is still expanding, but the rise in cases and deaths has slowed globally, except for Southeast Asia and the eastern Mediterranean regions, the World Health Organization (WHO) said.

In its latest epidemiological update, issued on Monday night, it said that the Americas remains the hardest-hit region, accounting for half of the newly reported cases and 62% of the 39,240 deaths worldwide in the past week.

More than 23.65 million people have been reported to be infected by the coronavirus globally and 811,895 have died, according to a Reuters tally on Tuesday.

"Over 1.7 million new COVID-19 cases and 39,000 new deaths were reported to WHO for the week ending 23 August, a 4% decrease in the number of cases and (a 12% decrease) in the number of deaths compared to the previous week," the WHO said.

Southeast Asia, the second most affected region, reported a jump accounting for 28% of new cases and 15% of deaths, it said. India continues to report the majority of cases, but the virus is also spreading rapidly in Nepal. 
 
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In WHO's eastern Mediterranean region, the number of reported cases rose by 4%, but the number of reported deaths has consistently dropped over the last six weeks, the WHO said. Lebanon, Tunisia and Jordan reported the highest increase in cases compared to the previous week. 
 
<a href="https://www.wionews.com/world/worlds-first-coronavirus-reinfection-case-confirmed-in-hong-kong-322896">Also read | World’s 'first' coronavirus reinfection case confirmed in Hong Kong</a> 
 
The number of cases and deaths reported across Africa decreased by 8% and 11% respectively in the past week, "primarily due to a decrease in cases reported in Algeria, Kenya, Ghana, Senegal and South Africa", it said.

"In the European region, the number of cases reported has consistently increased over the last three weeks," it said. "However, only a slight decrease (1%) was reported in the most recent week, and the number of deaths has continued to decrease across the region."

In WHO's western Pacific region, the number of new cases dropped by 5%, driven by less spread in Japan, Australia, Singapore, China and Vietnam. South Korea reported an 180% jump in cases, "mainly due to an increase in cases associated with religious gatherings".

The COVID-19 pandemic is still expanding, but the rise in cases and deaths has slowed globally, except for Southeast Asia and the eastern Mediterranean regions, the World Health Organization (WHO) said.

The COVID-19 pandemic is still expanding, but the rise in cases and deaths has slowed globally, except for Southeast Asia and the eastern Mediterranean regions, the World Health Organization (WHO) said. In its latest epidemiological update, issued on Monday night, it said that the Americas remains the hardest-hit region, accounting for half of the newly reported cases and 62% of the 39,240 deaths worldwide in the past week. More than 23.65 million people have been reported to be infected by the coronavirus globally and 811,895 have died, according to a Reuters tally on Tuesday. "Over 1.7 million new COVID-19 cases and 39,000 new deaths were reported to WHO for the week ending 23 August, a 4% decrease in the number of cases and (a 12% decrease) in the number of deaths compared to the previous week," the WHO said. Southeast Asia, the second most affected region, reported a jump accounting for 28% of new cases and 15% of deaths, it said. India continues to report the majority of cases, but the virus is also spreading rapidly in Nepal. Also Read: South Korea orders schools to be shut in Seoul amid surge in virus cases In WHO's eastern Mediterranean region, the number of reported cases rose by 4%, but the number of reported deaths has consistently dropped over the last six weeks, the WHO said. Lebanon, Tunisia and Jordan reported the highest increase in cases compared to the previous week. Also read | World’s 'first' coronavirus reinfection case confirmed in Hong Kong The number of cases and deaths reported across Africa decreased by 8% and 11% respectively in the past week, "primarily due to a decrease in cases reported in Algeria, Kenya, Ghana, Senegal and South Africa", it said. "In the European region, the number of cases reported has consistently increased over the last three weeks," it said. "However, only a slight decrease (1%) was reported in the most recent week, and the number of deaths has continued to decrease across the region." In WHO's western Pacific region, the number of new cases dropped by 5%, driven by less spread in Japan, Australia, Singapore, China and Vietnam. South Korea reported an 180% jump in cases, "mainly due to an increase in cases associated with religious gatherings".

Pandemic pace slows worldwide except for Southeast Asia, Eastern Mediterranean: WHO

World's first case of Coronavirus reinfection has been found in Hong Kong. A 33-year-old man had a different strain of the Coronavirus than the one he was previously infected with in March.

COVID-19 reinfection: Hong Kong reports world's first 'proven' case

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