The Lancet: Pfizer vaccine antibody concentration dropped by more than 50% within 10 weeks of vaccination!

Recently, the domestic new crown epidemic has resumed, and there are more and more local cases in Nanjing and Zhengzhou, Henan.

On July 15, 2021, a new data based on the UCL virus observation study published in The Lancet showed that total antibody levels seem to begin to decline as early as six weeks after full vaccination, and can be reduced by 50% within 10 weeks.

The study found that in the data of more than 600 people, for Pfizer vaccine, the antibody level dropped from a median of 7506 U/mL at 21-41 days to 3320 U/mL at 70 days or more

The level at a determined time point after the second dose of vaccination (with an extended dose interval), the level of SARS-CoV-2 spike glycoprotein antibody (S-antibody)

In addition, the study also showed that the antibody level after two doses of Pfizer vaccine was much higher than two doses of AZ vaccine

The authors emphasize that although the clinical significance of the decline in antibody levels is not clear, some declines are expected, and current research shows that vaccines are still effective against serious diseases

Dr.

Professor Rob Aldridge (UCL Institute of Health Informatics) explained

Our findings support the recommendation of the Joint Committee on Vaccination and Immunization (JCVI) that clinically vulnerable adults, people 70 years of age or older, and all residents of nursing homes for the elderly should receive booster doses first

The authors pointed out that the limitations of the data include the small sample size of some groups, and each person only contributed one sample, so they cannot confirm how fast each person's antibody level is falling, or whether these antibody levels will continue to decline or Reach a stable level in the next few months

Further research is important to determine whether there is a threshold for antibody levels needed to protect people from serious diseases

"When we plan vaccination programs around the world, we need to take into account the weakening of immunity and the possible need for booster doses - in the case of limited global vaccine supply, we need to protect our most vulnerable groups through booster doses.

References: Madhumita Shrotri et al, Spike-antibody waning after second dose of BNT162b2 or ChAdOx1,The Lancet(2021).