Report finds almost 100% of people tested positive for antibodies after second vaccine dose

A new report from Imperial College London and Ipsos MORI has shown that almost 100% of people tested positive for antibodies 14 days after their second dose of the Pfizer/BioNTech or AstraZeneca COVID-19 vaccines.

The latest antibody surveillance report saw over 207,337 participants test themselves at home using a finger prick test between 12 and 25 May 2021.

The aim of the report is to track COVID-19 antibodies across England, following either natural infection with the virus or after vaccination.

The proportion of people testing positive for antibodies following one dose of either vaccine peaked at four to five weeks after the first dose, and started to decline before rising again ‘substantially’ for those who had a second dose.

According to the findings, over 90% of people aged over 65 years old tested positive for antibodies, jumping to 95% in those aged over 75 years old.

The report also found that 36% of people aged 18 to 24 years old tested positive for antibodies, with a quarter of respondents in this age group reporting that they had received one or two jabs compared to 99% of those aged over 75 years old at the time of the report.

Other findings from the study show that the prevalence of antibodies was 30% lower in men compared to women.

This is due ‘in part’ to uptake of the vaccine, as 75% of women had received at least one vaccine dose compared to 70% in men.

Women were also found to have a higher antibody positivity after a single dose of the vaccine compared to men.

“It is incredibly reassuring to see nearly every single person who took part in the REACT study developed detectable antibodies following two doses of the vaccine. It goes to show once again how two doses are vital for the best possible protection,” said vaccines minister Nadhim Zahawi.

“Our vaccination programme is working and is severely weakening the link between cases, hospitalisations and deaths. We are continuing to make strong progress in boosting uptake for people living in deprived areas, as well as black and minority ethnic communities by working closely with faith and local leaders,” he added.