Sumary of UK scientists back Covid boosters as study finds post-jab falls in antibodies:
- Scientists have backed proposals for Covid boosters in the autumn after blood tests on hundreds of people revealed that protective antibodies can wane substantially within weeks of second vaccine shots being given.
- The UCL Virus Watch study found that antibodies generated by two doses of the Oxford/AstraZeneca and Pfizer/BioNTech vaccines started to wane as early as six weeks after the second shot, in some cases falling more than 50% over 10 weeks.
- “We know levels of antibodies start high and drop substantially,” said Prof Rob Aldridge, an infectious disease epidemiologist at UCL.
- The UCL team analysed blood from 605 vaccinated people mostly in their 50s and 60s.
- They found that antibody levels varied widely between patients, but a double dose of Pfizer/BioNTech tended to produce far more antibodies against the coronavirus than two shots of the Oxford/AstraZeneca vaccine.
- Three to six weeks after full vaccination with Pfizer, antibody levels typically stood at about 7,500 units per ml, but more than halved to 3,320 units per ml after 10 weeks.
- For AstraZeneca, antibody levels peaked at about 1,200 units per ml and typically fell to 190 units per ml after 10 weeks.
- Since publishing the results in a letter to the Lancet, the researchers have seen the same trend in a further 4,500 participants in the study.