LONDON – A study in the United Kingdom shows that delaying the second dose of Pfizer-BioNTech mRNA vaccine can increase the antibody response after the second vaccine more than threefold in people over 80.
The authors say this is the first direct study of how such a delay affects coronavirus antibody levels and could influence vaccination planning decisions in other countries.
“This study also confirms growing evidence that the approach taken in the UK to delay the second dose has really paid off,” said Gayatri Amirthalingam, an epidemiologist with Public Health England in London and co-author of the preprint. press briefing.
Many COVID-19 vaccines are given in two doses: the first triggers an immune response, and the second, a “booster” vaccine, enhances it. Clinical trials of the three vaccines used in the United Kingdom typically showed a three- or four-week interval between doses.
But for some existing vaccines, a longer wait between the first and second doses produces a stronger immune response. Delaying COVID-19 vaccination may also increase partial immunity in a larger portion of the population than a shorter dosing schedule. On December 30, the UK announced that it would postpone the second dose for up to 12 weeks after the first.
“Our study demonstrates that peak antibody responses after a second Pfizer vaccine are markedly increased in older adults when it is delayed for up to 12 weeks,” said Helen Parry, study author at the University of Birmingham.
Britain began introducing the Pfizer vaccine prior to the dosing policy change, which means that a small number of people who had received the vaccine earlier received a second vaccine three weeks later.
The study, which has not yet been peer-reviewed, enrolled 175 people between the ages of 80 and 99 and found that extending the second interval between doses to 12 weeks increased the peak antibody response by 3.5 times compared to those with he was in three weeks. …
Antibodies are part of the immune system, and vaccines also generate T cells. Peak T-cell responses were higher in the group with a three-week interval between doses, and the authors cautioned against drawing conclusions about how protected people were based on which dosing regimen they received. – Agencies
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