Roughly two out of three Indians may have some protection from Covid-19, government experts on Tuesday said, citing the latest sero survey findings that they described as a “ray of hope”, but added that a large part of the population is still vulnerable and future waves cannot be ruled out. The study covered 28,975 people who were tested for antibodies for Sars-CoV-2. In all, 67.6% of the participants tested positive as a result of either an infection or because they took a vaccine. “Two-thirds of the general population, above the age of six, had antibodies. More importantly, a third of the population did not have antibodies, which is roughly 400 million people,” said Balram Bhargava, the director general of the Indian Council of Medical Research (ICMR), at the government’s routine press briefing. The official said that among the people surveyed, 12,607 did not take any dose of a vaccine. Among the rest, 5,038 had one dose and 2,631 had two. The seroprevalence among the unvaccinated was 62.3%. In those who had a vaccine, the prevalence rate was 81% for those with one shot, and 90% for those who took both doses.