A recent analysis by BJ Government Medical College (BJMC) has revealed that high levels of protection against Covid-19 have been detected in over 500 healthcare workers even three to seven months after taking two doses of Covishield.
In the study that involved 558 healthcare workers (HCWs), 94.4% were positive for Covid neutralising antibodies at the time of the study period after two doses of the Covid Vaccine
With high levels of protection (seroprevalence) in participants at this point, the study concluded that a third booster, while a chunk of the population is yet to get their second shots, may not be advisable, Dr Muralidhar Tambe, professor and Head of Community Medicine at BJMC, told TOI.
Dr Tambe said, “Though we found that the antibody prevalence decreased as the duration of interval increased after two doses of Covid vaccine, immunity levels remained high. Upon analysing the analysed antibody positivity in the serum of the study participants, the antibody positivity was at 96.77% at three months post full vaccination, rising to 100% at four months, and then falling to 91.89% at seven months after the initial two doses.”
Dr Tambe further added, “At the time of the study, some of these HCWs had already completed three months, while some had completed 4-7 months after two doses of Covid vaccination. In the next aspect of the study, we analysed antibody positivity in their serum according to the duration of time period competed after full vaccination. The blood samples were collected two months ago.”
He also informed that apart from 5 of the participants who had received Covaxin, all of them had received Covishield.
The researchers further stated that more research would be conducted on whether a booster dose should be recommended in individuals who have completed 9 months or more after their initial doses.