Past Covid infection plus vaccination 'gives greater protection'

Previous coronavirus infection gives double jabbed people greater protection, new research suggests.

Past Covid infection, together with being fully vaccinated, increases an individual’s protection against the virus to as much as 94%, according to the Zoe Covid study.

The research found two doses of Oxford/AstraZeneca provided 71% protection against infection up to six months after vaccination, while protection was increased to 90% among those who previously tested positive for the virus.

While two doses of Pfizer/BioNTech jab gave 80% protection up to six months after vaccination, which increased to 94% with a previous infection.

Professor Tim Spector, of King’s College London – a lead scientist on the Zoe Covid study app, said: “Regardless of which vaccine is administered, this latest research shows that having a natural Covid-19 infection before double vaccination does mean greater protection.

“This is really positive news for overall immunity levels in the UK and means that large numbers of people will have effective and long lasting protection from Covid-19.

“This is also strong evidence to support the need for vaccination, even for those who have already had Covid-19.”

Drawing on more than 1.2 million test results, the analysis found that a previous infection without vaccination gave only 65% protection.

Researchers say this suggests that on average vaccination provides better protection, and the addition of vaccination significantly increases protection.

The study also found that protection from a previous infection alone did not wane for up to 450 days after being infected – independent of vaccination status.

This is unlike vaccine protection, which the Zoe study has previously found starts to wane after three months.

According to the researchers, this suggests people who have had two doses on top of a previous infection are likely to maintain higher levels of protection from Covid-19 for longer than those who were not infected prior to their vaccination.

The study used data from vaccines which were logged from December 8 last year, to July 31 this year, and from infections which occurred between May 26 this year, when the Delta variant became dominant, and July 31 this year.

Prof Spector added: “When it comes to a booster jab, it’s my opinion that if you’re not in one of the eligible groups for a booster yet, but have a previous infection and two vaccines, you shouldn’t be too worried as your protection will be very high.

“It’s likely that there will be high levels of uptake in those who are double vaccinated and are invited for a booster, so it’s more important we focus on those who remain unvaccinated, which is still too high, and we are quickly falling behind the rest of Europe.”