In an attempt to understand the efficacy of the vaccine, the Ahmedabad Municipal Corporation (AMC) undertook a study to understand the seropositivity. According to the sero survey, almost 93 per cent of the 478 health workers from urban health centres and hospitals of AMC had antibodies against Covid-19 after taking either one or both the doses.
The sample is taken from the health workers who got vaccinated between January and May. All of the people who were sampled had taken Covishield. From the survey, six per cent of the people who had taken both the doses did not have any antibodies present in their bodies.
In the latter half of May, amidst the repudiation of the made in India vaccine, the AMC initiated a study to understand the efficacy of the vaccine.
Over a period of six months, they tracked the antibody titers every fortnight for the health workers who had taken one or both the doses. Since September, the samples are being taken once a month as there was no material difference in seropositivity in two weeks’ time.
The targeted sampling size was believed to be 1,009 health workers across UHCs from seven zones and five AMC hospitals which are CH Nagri Eye Hospital, LG Hospital, SVP Hospital, VS Hospital and SCL Municipal General Hospital.
However, August saw only 478 of the targeted health workers.
Of the 478 samples, 51 people had taken only the first dose. From the 51, only two did not form antibodies. Among the 427 who took both the doses, 398 had developed antibodies whereas 29 did not form antibodies even after being fully vaccinated. It is deduced that the antibodies are not present due to the elapsed time between taking the second dose and sampling for the 29 fully vaccinated subjects pointing out the possibility of the vaccine waning over an elongated time period.
