The paradox of Kerala’s high COVID-19 numbers

Merely going by the projected high figures from Kerala, one might be tempted to assign this to sheer mismanagement on the state’s part and to hold out states like Uttar Pradesh as a paragon of good pandemic management.
Health worker takes swab samples for COVID-19 testing as coronavirus cases surge in Kozhikode.
Health worker takes swab samples for COVID-19 testing as coronavirus cases surge in Kozhikode.
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Public health in India is a state subject, even as preventing the spread of infectious diseases is a responsibility the states share with the Union government. One can thus compare the performance of different states in dealing with their individual epidemics. However, how does one measure success, or lack of it, in dealing with a pandemic? And can Indian states learn from each others’ experience?

Currently, over 51% of cases in India are from the state of Kerala. Among the 37 districts in India reporting a high number of cases, 11 are from that state. Kerala is recording more than 23,000 COVID-19 daily cases as on August 11. It is the only state in India where the number of active cases is well in excess of one lakh at the moment.

With about 3.58 million (35.8 lakh) cases recorded in all so far, Kerala’s COVID-19 burden far exceeds that of Uttar Pradesh (1.7 million cases) and Bengal (1.5 million). For a state with a population of about 35 million, in comparison to Uttar Pradesh (about 230 million) and West Bengal (about 100 million), this is a substantial fraction. In terms of the fraction of active cases across India currently, Kerala, with 45%, and Maharashtra with 17%, lead all states. The three other southern states of Tamil Nadu, Karnataka and Andhra Pradesh contribute approximately 5% each.

From these numbers alone, one might be tempted to assign this to plain mismanagement on the state’s part and to hold out the state of Uttar Pradesh, for example, as a paragon of good pandemic management. Testing less simply means that you will detect fewer cases. Currently, Kerala tests 1.3 lakh samples a day. This is to be compared to the testing numbers of 2.1 lakh daily for Uttar Pradesh. Kerala’s population, however, is smaller than Uttar Pradesh, by a factor of 7. On a per-capita basis, thus, Kerala tests far more. West Bengal tests below 50,000 daily currently.

One way to determine whether these levels of testing are sufficient is to examine the test positivity ratio, the fraction of cases that test positive relative to the total number of tests done, converted into a percentage. On this count, Kerala does badly, with test positivities currently in the range of about 13%. Uttar Pradesh’s test positivity ratio is less than 0.1% at the moment.

However, a superficial view can be misleading, for two reasons. First, if a large fraction of the population has been infected already — say more than 70% to 80% — one expects test positivity to be low, simply because the pandemic evolves slowly once many people have already been infected and one is on the downswing of the epidemic curve. So a state may do better on this metric simply because a large number was infected in the past.

Second, at any stage of the pandemic, if one were to rigorously follow up contacts of those who test positive, one is more likely to find a positive among them. However, on the other hand, if one largely tests in areas where many people have been infected in the past, it will be hard to find anyone with a current, active infection. This may give a biased view — cases may still continue to be added in more remote villages and towns, but a testing strategy that centres on cities and district headquarters will simply not pick their cases up.

Thus, it’s not just the amount of testing but who is actually tested that should count. Kerala has indicated that it follows a policy of targeted testing. This could explain the larger figures of test positivity that the state has consistently shown. One simple indicator of an epidemic that has been competently addressed is the fraction of the population that has been infected over the two waves of COVID-19. Obviously here, a smaller fraction is better, since the ideal way of dealing with COVID-19 is to not get it at all. The seroprevalence associated with COVID-19 in Kerala is 44%, compared to an all-India value of 67%, although this number reflects both prior infections and vaccinations, since antibody levels are measured in the serosurvey. No other state has come this close to effectively protecting its population from the ravages of COVID-19 across the past year and a half.

What about mortality arising from COVID-19? This is an indicator of the ability of the health care system to ensure that even severe cases are less likely to end up dying. Kerala’s CFR — its case fatality ratio, or the number of fatalities from COVID-19 patients divided by the number of cases, appropriately lagged — is currently 0.5, compared to a nationwide average of 1.3.

On vaccinations, some smaller Indian states have done better. However, the percentage of (eligible) people in Kerala with at least a single jab is 55% compared to 33% nationally at the moment.

But perhaps the most important aspect of Kerala’s management of the pandemic has been the simple fact that its own health infrastructure has not been overburdened with cases of COVID-19. Consequently, though case numbers may appear to be large at the moment, hospital beds, ICUs and ventilators remain available. Indeed, even while several states ran out of oxygen around the peak of the second wave, and some fraction of the associated mortality in those states likely came from patients who could have survived had they received timely attention, Kerala did not witness the same shortages.

Other positives are the following. COVID-19 data from Kerala, although not perfect, is largely believed to provide an accurate picture. Being able to trust the quality of public data aids the formulation of policy measures. Kerala is also one of the two states in India, Maharashtra being the other, which has targeted sequencing of samples of the virus from all its districts, enabling the rapid identification of potential new variants.

Kerala has unique problems and these make its relative success even more unusual. It has a relatively old population, with the largest fraction of those over 60 among Indian states It is a high population density state that is also highly urbanised. It is well-connected internationally, being the state with the largest number of international airports among all Indian states. It is thus especially vulnerable to the entry of new variants from outside India.

The prevalence of diabetes, among other non-communicable diseases, is the highest in Kerala as opposed to the states. Diabetes is a co-morbidity that predisposes someone infected with COVID-19 to more severe outcomes upon infection. These factors should, by rights, have predisposed the state to worse outcomes, particularly from the point of view of mortality.

Why do cases refuse to subside?

Paradoxically, one can understand this as a result of how well Kerala handled its pandemic in the past. Given that about 55% of the state remains susceptible to COVID-19, a fraction far larger than other states, preventing the disease from spreading is a substantially more difficult task. This is also important because the far more transmissible Delta variant currently dominates across India.

What has Kerala got wrong?

Allowing elections to local bodies earlier this year should not have been a priority. Having relaxations for earlier religious festivals conveyed the impression that conducting local customs and religious festivals outweighed the public health considerations involved. There are some recent reports of local lockdowns not being adhered to with sufficient care. Clearly, test positivity levels in excess of 13% should mandate even more testing than the state is currently doing. Although Kerala is doing better on vaccinations than the national average, it should prioritise vaccinations even more, given that it has a large vulnerable population.

What should Kerala do now?

The state’s single-minded focus should be on taking measures to reduce the number of cases, through testing, tracing and isolation of positive cases. Although Kerala faces the same economic pressures to open as other states, it should fine-tune its lockdown policies on a local level further to ensure that a hasty opening up does not jeopardise past gains.

The upcoming Onam festival needs careful attention if that is not to nucleate a large number of super-spreading events. Kerala’s management of its pandemic so far contains lessons for other states, as indeed for other low-and-middle income countries. Whether these lessons will be remembered will depend very much on what the state chooses to do from now on.

The views expressed here are his own.

Gautam I Menon is a professor at Ashoka University, Sonepat and at the Institute of Mathematical Sciences, Chennai. He can be reached at gautam.menon@ashoka.edu.in.

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