Over 81% people in Ahmedabad have Covid-19 antibodies, serological survey finds
A serological survey of around 5,000 people from across Ahmedabad in Gujarat has shown that 81.63% of the people had developed antibodies against the coronavirus disease (Covid-19). The survey also showed that people who had received both doses of the Covid-19 vaccine had higher levels of seropositivity than those who are yet to be immunised against the disease.
The seropositivity survey to study the presence of antibodies against the SARS-CoV-2, the virus that causes Covid-19, was conducted by the Ahmedabad Municipal Corporation (AMC), news agency PTI reported. It was conducted between May 28 and June 3, when the second wave of infections was subsiding, the report showed.
As many as 5,001 samples were collected for the study and out of these, 32 samples were not considered citing various results. The results of the study were available for 4,969 samples that included 2,354 males and 2,615 females, Dr Bhavin Solanki, AMC medical officer of health, said, according to PTI. “We carry out sero-surveillance studies at regular intervals to detect antibodies. Overall, 80 per cent seropositivity has been detected in the general population of Ahmedabad. Those who took both the doses had high levels of seropositivity as compared to those who took none,” he added.
As many as 4,056 samples contained antibodies against Covid-19 with 81.63% seropositivity. “A total of 1,938 males demonstrated the presence of antibodies, giving the positivity of 82.33%, while 2,118 females, which comes to 80.99%, had antibodies. Thus, the seropositivity is higher among males as compared to females,” PTI reported, citing the report by the AMC. This also included over 80% of the samples that possessed the antibodies on account of previous infections or the vaccination or both.
Meanwhile, 2,887 people in the survey were not infected with Covid-19 in the past and were not vaccinated and 2,216 people among them had antibodies which accounts for 76.76%. On the contrary, 158 people were infected with Covid-19 in the past and also had taken two doses of the vaccine and 154 people among them had antibodies, the report further highlighted. Also, antibodies were found in 164 samples out of 173, who had Covid-19 earlier and had taken one dose of the vaccine.
Among people who were vaccinated, those with previous infections had more antibodies than those that were never infected and those who had taken two doses of the vaccine had higher seropositivity than those with only one dose.
“A majority of the vaccinated population in our sample were vaccinated with Covishield vaccine. Although there are very few who were vaccinated with Covaxin in our sample, people with Covaxin have slightly higher seropositivity as compared to Covishield,” PTI quoted from the survey. However, the report also highlighted that the available data is “insufficient” to comment on the status of herd immunity for the entire city. It further said that vaccination is needed for complete control over the pandemic situation.
(With inputs from PTI)