New research focuses on Covid-19 immunity

New studies show that previous Covid-19 infections provide some immunity for at least five months, but people can still carry the virus and infect it.

Experts warn that a small number of immunized people can still carry the virus to their nose and throat and therefore may be at risk of transmitting the virus to others.

Antibodies from past infections provide 83% protection against reinfection for at least 5 months, according to the first report from a study by the Public Health England (PHE) Siren.

This suggests that those who get sick in the first wave may now be vulnerable to catching it again.

Although reinfections in people with antibodies were rare, researchers identified 44 potential reinfections among the 6,614 participants who showed evidence of previous infections.

Professor Susan Hopkins, Senior Medical Advisor and Siren Research Leader at PHE, said: “This study provides the clearest picture of the nature of antibody protection against Covid-19, but it is important not to misunderstand these early findings.

“We have found that most people who are infected with the virus and develop antibodies are protected from reinfection, but this is not perfect and it is not yet known how long the protection will last.

“Importantly, we believe that people may still be able to infect the virus.

“This reassures you that you are already sick and protected, but you are very unlikely to develop a severe infection, but you can get an infection and infect others. There is a risk of

Since June, PHE has regularly tested tens of thousands of healthcare workers across the UK for new Covid-19 infections and the presence of antibodies that suggest they have been infected before. ..

Research leaders have made it clear that this first report does not provide evidence for antibodies or other immune responses from coronavirus vaccines and that no conclusions should be drawn about their effectiveness.

This non-peer-reviewed study will examine vaccine response later this year.

“Not 100% protection”

Scientists conclude that naturally acquired immunity as a result of past infections provides 83% protection against reinfection compared to those who have never had a previous illness. ..

They added that this seems to last at least five months after the first illness.

Studies continue to assess whether protection lasts longer, which means that people who get sick in the first wave may be able to get it again.

PHE states that early evidence from the next stage of the study suggests that some of these individuals may carry high levels of the virus and continue to infect others. It was.

Between June 18 and November 24, scientists detected 44 potential reinfections in 6,614 antibody-positive participants, with a protection rate of 83% from reinfection.

Professor Hopkins said he could be confident that five to six months after the initial infection, the majority of previously infected people would be protected from serious illness and symptomatological infections.

She added: “It’s good that it protects people, but it’s not 100% protected. So, until we know more about this, people still have to follow the rules for sustainability of their responses. Individuals are not responding or this is specific to a particular group. “

Professor Hopkins explained that when the study was designed, researchers were trying to ensure that they had the minimum immunity accepted by the vaccine.

She continued: “And then the vaccine efficacy study said,” Did the vaccine have 50% to 60% efficacy in reducing future symptomatological infections? “

“And from a symptomatic point of view, only a small percentage of 13 out of 44 people have symptomatological infections.”

Professor Hopkins added: “At least during this period, previous infections look as good as vaccines. This is very good news for the population and helps boost immunity alongside vaccines. Populations that begin to reduce infections.

“What we don’t know yet, and what this study is trying to do, is to determine the persistence of the reaction.

“Overall, I think this is good news. It can make people feel that a previous infection protects them from future infections, but at the same time it is not a complete protection, so be careful when you go out. And about. “

“It is highly recommended that people have immunity that lasts much longer than the months estimated before the summer,” said Professor Hopkins.