Ahmedabad has no herd immunity against COVID-19.
Ahmedabad Municipal Corporation’s medical officer, health, Dr Bhavin Solanki on Thursday said that a study carried out by the civic body has found that the city has no herd immunity.
The AMC carried out what is believed to be the biggest study in the world to know seropositivity as far as COVID-19 is concerned.
The serological study covered 30,054 samples from across seven zones of the city.
Solanki said the city had seropositivity of 17.61% which indicates that the city does not have herd immunity.
“Had the city achieved herd immunity the positivity would have been 70% to 80%,” said Solanki.
The seropositivity among females (17.98%) was slightly higher than males (17.21%).
What it means
The report released by the AMC said that 17.61% of seropositivity showed that majority of the population in the city was still susceptible to the disease
It said some results could also point out to vanishing immunity, meaning the immunity against the disease does not last long.
The report, however, said this can be found out only with the help of further studies.
It also clarified that reports of 49% seropositivity among Ahmedabad residents in an ICMR study was not true as it has not been declared officially.
It said the ICMR study only had 496 samples all of which were from containment zones.
It said the sample size of the AMC study was 60 times bigger than the ICMR study and hence a better representation of the population.
What should be done
The AMC said the city cannot rely upon herd immunity and should focus on preventive measures.
Wearing masks, maintaining social distance, washing hands and following, cough etiquettes are the best way to prevent the disease, AMC said.
The study revealed
The seropositivity of Ahmedabad is 17.61% as 5,263 out of 29,891 tested positive
Central zone with the highest caseload has the highest seropositivity of 28.43%
Health workers in the field area (8.98%) had higher positivity levels than those working at hospitals (5.26%).
More tests were conducted in the younger age group but higher positivity was found in the older age group
Among close contacts of COVID-19 patients, non-health workers had higher seropositivity than health workers