Beating disease “as good as” getting vaccine says scientists

The Times

Tom Whipple

Gerry Gajadharsingh writes:

“For many infectious diseases it is common that once someone has been infected it gives us at least some immunity, sometimes for a short time, sometimes for a long time and sometimes forever. The problem with coronaviruses is they have a habit of mutating, hence why the annual flu vaccine is a bit of a gamble each year and it just depends on how the authorities choose the actual mutation of the flu virus to develop a vaccine to try to protect us.

Clinicians have been wondering for a while and probably also hoping, that people who have already been infected with SARS CoV 2 (the coronavirus that causes COVID 19 disease) may well have developed some immunity probably through antibodies but also likely through other mechanisms in our immune systems such as T cell responses.

So, the below research is really good news. The takeaway is that it is highly likely that the millions of people in the UK, who have already been infected by the novel coronavirus, will have at least as good immunity as those people now receiving the vaccine. The headline figure is approximately 85% protection against both asymptomatic and symptomatic reinfection, similar to the vaccines being used in the UK at the moment. The other good news is that while a small number of people who had previously been infected did get infected again 0.66% (44 out of 6,600 healthcare workers), some suffered a mild form of the disease or mostly were asymptomatic.

So, the term heard immunity seems to be now back on the agenda (it never left mine), so hopefully a combination of immunity from previous infection and immunity from vaccination is what’s going to lead us to a more normal society.

So dark days will continue for the next few weeks and months, but light is definitely at the end of the tunnel.”

Contracting coronavirus gives “at least as good” an immune defence against future infections as a vaccine, according to the most comprehensive study into reinfection rates.

Previous illness provided about 85 per cent protection against both asymptomatic and symptomatic reinfection, researchers said after following thousands of people who caught the virus in the spring.

Although they found that a small number among the group did get infected twice, typically they suffered a milder form of the disease.

With an estimated one in five having been infected, the findings, based on a study of 21,000 UK healthcare workers, suggested that herd immunity could already be slowing the course of the pandemic. However, scientists warned that they still did not know how long immunity lasted.

“What that’s saying to us is that prior infection looks as good as the vaccine, at least at this time interval, which is very good news for the population,” said Susan Hopkins, deputy director of the national infections service at Public Health England (PHE). “It will help alongside the vaccine to give a level of immunity and protection that will start to reduce transmission.”

The research into immunity by PHE followed 6,600 clinical staff infected in the first wave, along with 14,000 who had remained healthy, regularly testing them to see whether they were subsequently positive.

By late November there were 318 infections among the 14,000 and at most 44 reinfections among the 6,600. Most of those cases were mild and showed no symptoms.

There was some uncertainty among the reinfection number, which may have been even lower. The scientists said they could not exclude the possibility that in some cases they were picking up evidence of the first infection.

Although the Pfizer vaccine has a headline efficacy rate of 95 per cent, that figure is based on symptomatic infections alone, so the mildest cases were ignored.

Professor Hopkins said the best way to think of it was that immunity from infection was as good as, or better than, a vaccine.

“The immunity gives you similar effects to the Pfizer vaccine, and much better effects than the Astrazeneca vaccine, and that is reassuring for people,” she said. Two doses of the Oxford-Astrazeneca vaccine offer 62 per cent protection.

However, she said it was not a licence to ignore social distancing. “It does seem that new infections can come. You can definitely get reinfected after primary infection,” she said but added that the risk of severe disease was extremely low.

“Overall I think this is good news, it allows people to feel that their prior infection will protect them from future infections, but at the same time it is not complete protection and therefore they still need to be careful when they’re out and about,” she added. “I am strongly encouraged that people have immunity that is lasting much more than the few months that was speculated before the summer.”

Simon Clarke, from the University of Reading, said the study had “major implications for how we can get out of the current crisis”.

He said: “The good news is that this study gives further weight [to the belief] that reinfections of Covid are rare, at least at this stage, and that having antibodies will provide protection for a meaningful amount of time, although it may not be lifelong immunity.” Julian Tang, from Leicester University, said that as hospitals became overwhelmed with a second wave, the results should “reduce the anxiety of many healthcare worker colleagues who have concerns about getting Covid-19 twice”.

Professor Neil Ferguson, whose modelling led to the first lockdown last year, said that the requirement to isolate after coming into contact with someone with coronavirus could be relaxed for people who have recently had the virus to ease pressure on the health service.

“Those people who have had the virus before are at less risk of getting infected and cumulatively slow the spread,” he told the Today programme on BBC Radio 4. “What it means for individuals is harder to say. We have a real problem at the moment, for instance with healthcare workers — a lot of healthcare workers getting infected and off work.

“Whether we can relax restrictions temporarily on requirements for isolation for people who have had a positive test in the last few months is a question for policy makers but it could ease pressures on, for instance, the health service.”

Victoria Atkins, the safeguarding minister, said that even if people have developed some immunity to the virus, everyone still needs to follow the government’s restrictions. “The message from government, I’m afraid, remains the same: all of the measures that we have, whether it’s ‘hands, face and social distancing’, all the lockdown measures that we are currently in, they all still apply,” she told Sky News.

“This vaccination news, or indeed the news that if you have already had Covid you might have some immunity, that’s great news for the future but we all must play our part in sticking to the rules so we can start to, in due course, release these lockdown restrictions and get back to some form of normality.”

The findings may also lead to renewed calls for those who have been infected to be moved further down the queue for the vaccine. The joint committee on vaccination and immunisation, which decides vaccine priorities, has previously resisted that idea.

The researchers next want to look at the effect of the vaccine on those with a previous infection.

This week Edge Health, a data consultant, estimated that 12.4 million people had been infected in England, equivalent to one in five of the population.