Also Read | Churn in India’s internet economyA follow up on 346 seropositive individuals among the samples after three months revealed ‘stable’ to ‘higher’ antibody levels against SARS-CoV-2, but declining plasma activity for neutralizing the virus, Shantanu Sengupta, senior scientist at IGIB and one of the co-authors of the paper said.A repeat sampling of 35 individuals, at six months, revealed declining antibody levels while the neutralising antibody remained stable compared to three months.However, both the normal antibody as well as the neutralising antibody were much above the required threshold, he said.“Our finding that smokers are less likely to be seropositive is the first report from the general population and part of growing.