COVID infection plus double vaccine gives maximum protection: UK study

Recovery after a previous COVID infection followed by being double vaccinated increases an individual's protection against COVID-19 to as much as 94 per cent, a new real-world UK study revealed on Thursday.

The ZOE COVID Study, a not-for-profit app-based initiative that has been studying real-world data in the UK on COVID-19 since last year, found two doses of the Oxford/AstraZeneca vaccine – administered in India as Covishield – provided 71 per cent protection against infection up to six months after vaccination.

That protection was increased to as much as 90 per cent among those who previously tested positive for COVID-19.

“The good news this week is our latest research shows having a natural COVID-19 infection before double vaccination means greater protection,” said Professor Tim Spector, lead scientist on the ZOE COVID Study app.

“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,” he said.

“The evidence supports the need for vaccination, even for those who have already had COVID-19. We need to be less complacent and without restrictions much more focus needs to be put on getting everyone vaccinated before winter to keep up with other countries' efforts,” he added.

Two doses of the Pfizer/BioNTech mRNA vaccine, the other vaccine being administered in the UK, gave 80 per cent protection up to six months after vaccination, which increased even further to 94 per cent with a previous COVID-19 infection.

The findings also note that the number of daily new cases continues to increase rapidly in the under-19 age group, with cases rising in the 30-49 age group at a slower rate. According to the ZOE prevalence data, it is estimated one in 30 children aged between 10-19 currently have COVID.

“While COVID may be less severe in children, allowing COVID to run rampant among them is a real gamble,” notes Professor Spector.

“Without vaccination or restrictions in this group, we can only hope that some kind of herd immunity will kick in and cases will drop,” he said, warning of long-term effects unless the spread in children is monitored closely after schools reopened fully in recent weeks.