A new sero-survey conducted by the Gujarat’s Ahmedabad Municipal Corporation (AMC) has revealed that 40 per cent of patients who recovered from Covid-19 did not have the antibodies three months after they were infected.
This raises concerns of re-infection among the Covid-survivors with the municipal corporation officials not ruling out second wave of the disease.
The survey showed that just 23.24 per cent of samples had antibodies against coronavirus, indicating that the city has not developed a herd immunity, an official said even as he warned that the city might witness a possible second and even a third wave of Covid-19 infections, if basic rules of Covid hygiene are not followed.
“At this rate, a second or a third wave of Covid may follow, if precautions are not taken now,” the official warned. However, much better picture will emerge from the results of the second sero-survey conducted by the Centre in 18 districts across the country.
“Results will be out within a week,” Rajesh Bhushan said at a press briefing here.
The antibody study in Ahmedabad was conducted between August 15 and August 29 over a representative sample size of 10,000 people. It found that 23 per cent of the sampled population had Covid antibodies, while in the last survey conducted in June where a larger 30,000 people were sampled 17.6 per cent people had developed antibodies.
Another clear sign of people shedding antibodies over a period of time is seen in the municipal Central zone which had seen the outbreak in March-April where there is just a 3.2 % rise in population having developed antibodies now, compared to June. Another such zone is the East zone where there has been a marginal rise of 0.74% population having antibodies against Covid.
Dr Jay Shah, associate professor of AMC MET and Amit Parikh, HOD medicine, in SVP hospital said that the increase in positivity of 5.63 per cent in the city after 1.5 months of earlier study, and in Unlock period, is very low.
“We are fine-tuning our results. One task is to find whether these tests were showing presence of other coronaviruses along with Covid-19 and another is to find how much time one takes to shed the antibodies. The Central zone and East zones are clear examples of shedding antibodies,” said the official.
