Results of the fourth round of sero prevalence survey conducted by the Indian Council of Medical Research (ICMR) in three districts in the State, as part of the nation-wide survey it had conducted in June to determine the extent of the exposure of the population to SARS-CoV-2, reveals that more than 50% of the State’s population is still vulnerable to COVID-19.
While this can be seen as a success of the State’s containment measures and the high level of compliance of the general population to COVID protocols, the other side of the story is that, having spread out the epidemic curve, Kerala is likely to live with COVID-19 for a very long time.
The fact that the sero prevalence in the State is 42.7% against the national average of 67.6% indicates that herd immunity against COVID is still a long way off in Kerala.
The epidemic is going to be protracted, the curve is likely to remain high for a long time, with intermittent surges or waves. The State and the community will need to maintain constant and continuous vigil so that the surge in cases is always contained at a level where it does not threaten the surge capacity of the health system.
Vaccination against COVID also becomes a priority for the State and even though vaccines afford only a limited level of protection and will not prevent infections, it will certainly help to reduce hospitalisations and deaths.
The ICMR’s fourth round of sero survey was done in the same 70 districts across the country where the first three rounds had been held. In the first round in May, Kerala’s sero prevalence had been 0.33% (national average of 0.73%), in August it was 0.88% (6.6%) and in December it was 11.6% (21%).
Sero positivity in Thrissur was 47.1%, Ernakulam 39.1% and Palakkad, 42%.
The ICMR said that in the fourth round of the survey, about 57% of the children in the 6-17 years age group had antibodies against COVID. It recommended that children are relatively protected against COVID and that when schools are reopened, primary schools should be opened first.
However, Kerala will have to do its own sero survey, with a good sample size and sufficient sub group samples to assess the proportion of its children who are vulnerable, before it can even contemplate school reopening.
While there are recent indications that infection rates in the 0-19 years age group is rising in the State (mass testing last week found that the highest test positivity rate of 25% was found in children), the ICMR survey reveals that a chunk of the State’s adult population is still vulnerable.