A Lancet study has said that levels of antibody from Covid-19 vaccines may decline in 60 to 90 days. It said that two doses of Pfizer and AstraZeneca vaccines offer good protection from the virus. The antibody levels developed are substantially higher. But it starts diminishing after six of the second dose. The study said that antibody levels could reduce by around 50 percent over 10 weeks. The study was done at the University College London. Researchers said that the drop in antibody levels is a cause of concern. They said that this could weaken the body’s levels to fight off new variants. They, however, didn’t predict how soon mutation can happen.
Researchers said that high antibody levels are important in the fight against the virus. The vaccines do develop very high antibody levels to protect against severity. For the study, researchers analyzed the data of 600 people. All the participants were above 18 years of age. They were fully vaccinated. They found antibody levels after two doses are consistent across all age groups. They, however, said that clinical implications of lowering antibody levels after two to three months are yet to be established. A decline was surely expected earlier after a certain period. But the latest study shows that the reduction could be more than 50 percent. Researchers said that vulnerable adults should be given priority for booster doses.
Researchers said that those given the AstraZeneca vaccines are most likely to have the lowest antibody levels than those vaccinated with the vaccine manufactured by Pfizer. They recommended that this should also be taken into account while deciding who all be given the booster dose at the earliest when available. Researchers also said that there were limitations in the data as it involved a small sample size. Each individual contributed one sample. They added that immunity levels differ from person to person. It depends on the body’s ability to fight against the virus and also T-cell responses.
