India's seroprevalance survey shows only 21% seropositivity to #Covid19 ,hardly enough to have created herd immunity. Yet cases are falling consistently. There are 3 broad areas we need to work on to figure out why.
1. Innate issues with the Virus- A weakened strain,

2. Environmental factors-Virus is virulent as before but something in the environment is preventing it from causing infections.
3.Immunity developed in population. Immunity is broadly of 2 types, Cell mediated & antibody mediated. Seroprevalence surveys measure only antibodies

With 21% antibody positivity rate, herd immunity is very unlikely. So it must be T-Cell immunity that needs to be looked at. This is difficult to measure but can be done in a few centers. However of late tests like the T Spot test enable rapid detection.. #CovidVaccines

of T-cell immunity. We need to be investing in these diagnostic technologies.35000 cr rupees is to be spent on a vaccine which many Indians may not need. We need to invest a fraction of this to see why more Indians have not been infected &if they need the vaccine at all. #COVID

@MoHFW_INDIA @ICMRDELHI @Vijayabaskarofl @RAKRI1 @doctorsoumya @GKangInd @AnooBhu