BENGALURU: In order to test antibody levels and check whether they have waned over a period of six months, and also judge the need for vaccine booster doses, Sri Jayadeva Institute of Cardiovascular Sciences and Research is conducting a retest on healthcare workers. These workers were vaccinated with both doses by February this year, and when tested for antibodies in April, they showed a good response.
The study will be repeated in September with the same set of people, at this hospital. “When we tested them in April, 80 per cent showed good antibody response. By the time we conduct the retest, six months would have elapsed since both the doses. If the drop in antibodies is significant, there may be a justification for booster doses, at least for those with comorbidities, those in hospitals and frontline workers. It is not possible to give everyone a booster dose as people have not completed their first and second doses yet, especially due to short supply of vaccines. We need to have our own data. If antibody levels have not dropped, it will give confidence to vaccine beneficiaries,” said Dr C N Manjunath, director of Sri Jayadeva Institute of Cardiovascular Sciences and Research.
Dr Manjunath said there is a need to reduce the interval between the first and second vaccine doses. It can be reduced from 12-16 weeks to 6-8 weeks. Otherwise, if people get infected in between, antibodies from the first dose may not be sufficient to fight off the infection. The second dose generates the best antibodies, he said.
However, there is a divide among the medical community on the need to test antibodies, and on booster doses. “It is not correct to constantly check antibodies and give booster doses. It is not sensible or scientific and there are always financial interests involved,” said epidemiologist Dr Jayaprakash Muliyil, a core member of the National Technical Advisory Group on Immunisation.
“Both natural infection and vaccination produce long-lasting immunity. We don’t need a continuous state of antibodies. Antibodies will come down after a while but when there is an infection, the body will remember and fight back. When the body is again exposed to the Covid-19 protein, it will respond when stimulated, and produce antibodies.
There is no need to have high levels of antibodies always, we just need the ability to fight back,” Dr Muliyil explained. He said that antibodies do not show the whole dimension of the immune profile. If you get breakthrough infection (infection despite vaccination), the body will be able to fight back appropriately and it will not be serious, he added.