LONDON, Feb. 25 (Reuters) – People in England receiving two doses of Pfizer COVID-19 vaccine produce strong antibodies as the shot is rolled out, researchers said on Thursday, adding that confidence in vaccines was high.
A survey by Imperial College London showed that 87.9% of people over the age of 80 tested positive for antibodies after two doses of Pfizer-BioNTech vaccine, which rose to 95.5% for those under 60 years of age. and 100% for those under 30 years.
“Although there is a slight decrease in positivity with age, we are getting the very good response at two ages to two doses of the vaccine,” Paul Elliott, chair of epidemiology and public health medicine at Imperial College London, told reporters.
Antibody levels are only one part of the immune picture, and vaccines are also shown to provide strong T-cell protection.
Nearly 95% of those younger than 30 years tested positive for antibodies 21 days after one dose, but this fell in older groups.
The study found that 34.7% of 80-year-olds or older generated antibody responses from a single dose of Pfizer vaccine, but the UK’s Vaccine and Immunization (JCVI) previously found high protection against the Pfizer vaccine after one dose, even when the antibody level is lower.
Britain has widened the dose gap to 12 weeks, although Pfizer has warned that it has only clinical efficacy with a three-week gap between shots.
More than 154,000 participants participated in Imperial’s home surveillance study for COVID-19 antibodies between January 26 and February 8, which monitors the antibody levels of natural infection as well as among the vaccinated.
The survey also looked at confidence in vaccines and showed that it was high, with 92% accepting or planning a vaccine offer, although confidence among black people was lower and dropped to 72.5%. (Reporting by Alistair Smout; editing by Giles Elgood)