A NEW study published on Thursday (25) revealed that people in England who have received two doses of Pfizer Covid-19 vaccine are generating strong antibody responses.
Researchers also said that confidence in vaccines was high.
An Imperial College London survey showed 87.9 per cent of people over the age of 80 tested positive for antibodies after two doses of the Pfizer-BioNTech vaccine, rising to 95.5 per cent for those under the age of 60 and 100 per cent in those aged under 30.
"Although there is some fall-off in positivity with age, at all ages, we get that very good response to two doses of the vaccine," Paul Elliott, chair in epidemiology and public health medicine, Imperial College London, told reporters.
Antibody levels are only one part of the immunity picture, with vaccines also shown to generate strong T-cell protection.
Nearly 95 per cent of under-30s tested positive for antibodies 21 days after one dose, but this fell in older groups.
The research found 34.7 per cent of those 80 years or older generated antibody responses from one dose of Pfizer vaccine, but Britain's Joint Committee on Vaccination and Immunisation (JCVI) has previously found high protection from the Pfizer vaccine after one dose, even when antibody levels are lower.
“These findings shed more light on rates of antibodies across the UK and among different groups, as we continue to strengthen our understanding of Covid-19. It is fantastic to see over 90 per cent of people surveyed would accept or had already accepted a vaccine, as we continue to expand the roll-out," said health secretary Matt Hancock.
“I urge anyone who has been invited for a vaccine to book an appointment. And while we are seeing rates of the virus gradually decline it is important we all hold our resolve and follow the rules as we deliver on our cautious but irreversible approach to easing lockdown.”
Britain has extended the gap between doses to 12 weeks, even though Pfizer has cautioned it only has data for clinical efficacy with a three-week gap between shots.
Over 154,000 participants took part Imperial's home surveillance study for Covid-19 antibodies, which monitors antibody levels from natural infection as well as among the vaccinated, between January 26 and February 8.
The survey also looked at confidence in vaccines, and showed it was high, with 92 per cent having accepted or planning to accept a vaccine offer, though confidence was lower among Black people, dropping to 72.5 per cent.
