Almost 100% of people test positive for antibodies after two COVID-19 vaccine doses

The latest findings from Imperial College London and Ipsos MORI’s report show that almost 100% of people had antibodies after their second vaccine after over 207,337 participants took part in a home surveillance study in May this year.

The proportion of people testing positive for antibodies peaked at 4-5 weeks after the first dose, before declining and then rising substantially after the second.

Over 90% of people aged over 65 tested positive for antibodies, rising to 95% in those aged over 75 with 36% of 18 to 24 year olds testing positive. At the time of the report, a quarter of respondents aged 18 to 24 said they had received one or 2 jabs compared to 99% of those aged over 75.

Other findings from the study show:

• prevalence of antibodies was 30% lower in men than women. This is in part due to uptake of the vaccine as 75% of women had received at least one vaccine dose compared to 70% of men. Women also showed a higher antibody positivity after a single dose of vaccine in comparison to men
• people in most deprived areas were least likely to have had a vaccine
• there was higher vaccine uptake in the highest income households
• those who work in retail, hospitality, and personal care such as hairdressing were 20 to 30% less likely to have been vaccinated than other workers
• compared to participants reporting white ethnicity, there was a 14% higher vaccine uptake in those reporting Asian ethnicity, and a 60% lower reported uptake in people reporting Black ethnicity
• people who had previous COVID-19 were 40% less likely to be vaccinated than those with no history of COVID-19.

Professor Helen Ward, Professor of Public Health at Imperial College London, said:

“Results of this very large study show the substantial impact of the vaccination programme on antibody positivity in adults. However, coverage of vaccines is uneven with people in some groups and areas less likely to have been vaccinated.”

She added:

“It is concerning that people on low incomes, in deprived areas, some minority ethnic groups and in some public facing occupations such as hospitality, may remain relatively unprotected from future spread. We need to continue and intensify efforts to reach these groups with vaccination, and to ensure other protective measures are in place.”

In total, 34,997,491 million people in the UK received both doses of vaccine, and the government achieved its target of every adult being offered a first dose by Freedom day, July 19.