With the estimated effective reproduction number for COVID-19 (a measure of the disease’s transmission potential) in the State still remaining high at 1.21, it is possible that Kerala’s agony over COVID-19 could be extended over many more months, epidemiologists and public health professionals now say.
On one hand it spreads out the infection over a period, helping the State to keep the case fatality down. On the other hand, the adverse impact on economy and COVID-related psycho-social issues could be prolonged.
There is speculation that Onam celebrations and the widespread political agitations that followed soon after, may have taken the epidemic curve to a new trajectory, with the result that predictions about the epidemic’s peak have become uncertain.
“Compared to the previous weeks, the doubling time has increased slightly and the case estimations, while still significantly high, have come down a notch. The new restrictions imposed by the State and the general sense of fear might bring down cases slightly in the next two weeks, it is hoped. However, the upcoming Sabarimala pilgrimage could upset all that and take the State to another peak,” says a senior public health professional.
Whatever be the interventions at disease containment, the epidemic has a natural logic which cannot be defied. Case numbers will continue to go up and one can only amp up the preparedness to meet it face on, he points out.
“Accuracy of projections depends on how unbiased the data are. We are not sure how unbiased the test positivity data are because testing is generally done in people who are symptomatic/high risk and the question is whether we should expect that in the general population. For projections to be accurate, we need data collected in a randomised surveillance mode,” says K.P. Aravindan, a public health professional.
“We thought that we would be peaking by October. But the results of the second round of ICMR’s sero surveillance study done in three districts in the State have now prompted a re-think that the peak is still far away. The sero prevalence rate of 0.8% in August in Kerala against the national average of 6.6 % seems way too low,” he adds.
But then, ICMR’s sero prevalence study was not State specific and it was done only to estimate a national average. The sample size was low at 1,281 samples and the districts covered were Thrissur, Ernakulam, and Palakkad.
Underestimation?
It is possible that the ICMR sample may have given an underestimation of actual sero prevalence in the State because it does not include data from a district such as Thiruvananthapuram where disease transmission has been intense in coastal areas where huge clusters had developed.
“Which is why it is important for the State to do a well-designed sero prevalence study on its own in all districts, with the help of any scientific institution. It will help us give unbiased data, which can also help us make better case projections,” Dr. Aravindan says.