The Kerala paradox of COVID-19 second wave

Why a state with the best health & education parameters consistently reports a high number of cases when others don’t 

By Vibha Varshney
Published: Thursday 07 October 2021

India‘s fight with the novel coronavirus disease (COVID-19) pandemic began January 30, 2020, from Kerala. Though the southern state seemed vulnerable at first, its slew of simple strategies yielded stellar results and were soon hailed as the benchmark for handling COVID-19. The state set a precedent by proactive inter-ministerial coordination, contact tracing of possible infected persons through a network of healthcare workers and a ban on public gatherings weeks before the Union government followed suit.

Now, Kerala is again in the eye of the storm. It has been accounting for half of India’s caseload since the end of July even as the national daily numbers have reduced to less than 10 per cent of the peak number of over 400,000, recorded during the first week of May 2021. Data with the Union Ministry of Health and Family Welfare shows that on September 19, Kerala was responsible for 19,653, or 64 per cent, of the 30,828 new cases recorded in the country.

Source: COVID19 India dashboard

Maharashtra was a distant second, accounting for 11 per cent of the new cases. Some 13 per cent of Kerala’s 35 million population have so far contracted the disease, the highest in any state in the country. It is followed by Goa (12 per cent) and Delhi (9 per cent). Does this mean Kerala has failed to handle the pandemic this time around?

Not really, if one takes a look at the state’s COVID-19 death rate; with 0.5 deaths per 100 confirmed cases, Kerala fares among the best in the country.

Down To Earth analysed the data and spoke to epidemiologists and other experts to understand the dichotomy: why the celebrated Kerala model failed during the current wave and how despite the high caseload, the death rate remains low. While there are several broad theories, answers to many critical questions are yet to be found. They hold an important message for the country, which, many say, will experience new surges in the future.


Superspreader events during the one-month lull could have led to the surge

Since the beginning of the pandemic, Kerala’s COVID-19 graph has been different from that of the entire country. But the trend has somehow reversed in recent months. While India’s second wave erupted mid-February, it reached Kerala much later by the end of March. The country came out of the second wave by May 8, and experienced a three-month lull before reporting another surge on August 24.

Kerala, in contrast, saw a much shorter one-month break, from May 15 to June 22, before cases started to rise again, says Sitabhra Sinha, professor of theoretical physics at the Institute of Mathematical Sciences, Chennai. His estimation is based on the R value, a measure that shows the number of people an infected person will pass on a virus to, on an average.

Source: COVID19 India dashboard

Sinha’s analysis further shows that the state might have experienced two events in March 15-22 and mid-June that led to the rapid spread of the disease. Kochi-based public health expert Antony Kollannur says the first superspreading event could be the political rallies and door-to-door campaigns that were carried out in March for the elections of local governments such as panchayats and municipality. The trigger for the second event, however, remains unexplained as the state was under lockdown between May 6 and June 16.


Kerala has lowest share of people with antibodies against COVID-19. Why?

There are only two ways for one to develop antibodies against a virus: From infection or through vaccination. The latest national serosurvey by the Indian Council of Medical Research (ICMR) in June-July 2021, shows only 44.6 per cent of the people in Kerala have developed antibodies against the virus, SARS-CoV-2, which is the lowest in the country. This is when data with the Union health ministry suggests that by the end of July, COVID-19 had infected 10 per cent of the population in Kerala, the highest after Goa where 12 per cent people were infected.

Sources: Union Ministry of Health and Family Welfare and Indian Council of Medical Research

The state also had an uncomfortably high test positivity ratio (confirmed cases per 100 tests) of over 13 per cent, which suggests a high penetration of the virus in the state. Further, Kerala had completely vaccinated 23 per cent of its adult population and administered the first dose to 54 per cent till July 31, which was much higher than the national average.

The incongruity is puzzling as ICMR in its serosurvey had found antibodies against SARS-cov-2 in two-thirds of the population (above six years) at the national level; antibodies were also found in 80 per cent of the people who received one vaccine.

Health experts have failed to explain this aberration and suggest Kerala-specific studies need to be carried out to understand the phenomenon.


Kerala has high diversity of variants and lineages, unlike other states

Some epidemiologists have in the past claimed that Kerala might have encountered a new variant of the virus. Data from genomic surveillance by the Indian SARS-CoV-2 Consortium on Genomics (INSACOG), a forum set up under the Union health ministry in December 2020 to study and monitor variation of circulating strains of COVID-19, however, suggests that the current variants in Kerala are also found in other states.

Globally there are four variants of concern, as per the World Health Organization. The Alpha variant (B.1.1.7), which was first reported in the UK in September 2020; the Beta variant (B.1.351), first reported in South Africa in May 2020; the Gamma variant (P.1), first reported in Brazil in November 2020, and the Delta variant (B.1.617.2), first isolated from India in October 2020 before spreading to 180 countries.

Over time, the Delta variant has developed 13 lineages that are named with the prefix AY. As of now, these lineages behave similar to the parent variant, but if they start to behave differently, they could be identified as a new variant.

The COVID-19 Genome Surveillance portal, which is run by independent researchers based on data from INSACOG and other sequencing initiatives by states, suggests that Kerala does not have a new variant so far. But it has a high diversity of variants and lineages.

Samples from Kerala show the presence of Delta variant and at least three of its lineages, along with other variants. Maharashtra, which has the second highest share in the new cases, shows the presence of Delta and Beta variants along with two Delta lineages.

The difference in the variant diversity explains why states neighbouring Kerala are not showing a surge in cases. In Karnataka, for example, 90 per cent of the samples have the Delta variant and 1 per cent has lineage AY.4.

The lineages could be the reason for the difference in the pandemic prevalence in southern and northern states. However, little data is available for most northern states, which hinders the possibility of making a definitive observation. Bihar, for example, has sequenced only 336 samples, which is miniscule when compared with Kerala’s 6,761 samples. In fact, India has so far sequenced 63,990 samples, which is only 10 times more than that of Kerala.


Kerala protected 90 per cent of its population during first wave, leaving them vulnerable to virulent variants

“If the spread of the virus is controlled, as it happened in Kerala, the infection lasts much longer than normal,” says Rajeev Sadanandan, former additional chief secretary of Kerala's Department of Health and Family Welfare. Kerala protected almost 90 per cent of its population during the first wave, leaving them vulnerable to the more virulent variants like delta.

A similar trend can be observed in other countries with good healthcare systems. Israel, which quickly contained the spread of the pandemic and vaccinated a majority of its population by February 2021, is seeing a surge in cases. In such regions, people tend to become complacent and do not follow COVID-appropriate behaviour like wearing masks and maintaining social distance.

For instance, in May 2021, the US Centres for Disease Control and Prevention advised that fully vaccinated people could resume normal activities without masks and social distancing. Following a surge in cases, the US agency has now changed the guidelines.

“All countries that were smart enough to curb the spread of Wuhan D614G (the first identified mutation of SARS-CoV-2 virus) had to have more Delta cases,” says T Jacob John, a virologist based in Vellore, Tamil Nadu. Kerala has similar demographics and healthcare parameters as European countries, he adds.

A COVID-19 ward in the Government Medical College Hospital in Manjeri, in Malappuram district of Kerala on August 18, 2021 (Photo. Reuters)


“The virus is mysterious and there are no scientific explanations for Kerala’s outbreak. Health experts must acknowledge this,” says Kollannur. For instance, he adds, the ICMR serosurvey has found high antibody levels in the populations of West Bengal and Jharkhand. Yet West Bengal is reporting over 700 cases a day, while Jharkhand is reporting less than 30 cases.

A similar mismatch can be seen in the vaccination numbers. Despite high vaccination coverage, Karnataka (53.6 per cent) and Telangana (52.5 per cent) continue to report higher daily cases than states like Bihar and Uttar Pradesh that have much lower vaccination coverage.

Experts maintain that while the Kerala model may currently be on life support, it is far from dead. “Other states should learn from us,” says PK Jameela, member of the Kerala State Planning Board. “Our patients did not have to run around for ICU/ventilator beds. All patients who came to the public hospitals were given free treatment and medicines,” she adds. Besides, the state saw community participation (arogyasena, volunteers, students, non-profits and political organistions) in its fight against the pandemic.

The death rate has been among the lowest in the country despite the fact that the state has a high number of old people with comorbidities. In 2015, a little over 13 per cent of the state's population was more than 60 years old, which is higher than the all-India average of 8.3 per cent, as per the SRS statistical report 2015 released by the Union Ministry of Home Affairs.

Confident that the outbreak is well under control, Kerala Chief Minister Pinarayi Vijayan has been slowly easing the COVID-19 restrictions beginning mid-September. This is an unusual move as 13 out of the 14 districts in the state had test positivity rates over 10 per cent between September 10 and 16. ICMR recommends lockdowns for districts with such high positivity rates. The state government, however, does not appear interested because of the high economic cost.

Read Kerala can't withstand more COVID-19 lockdown: Thomas Isaac

As on Sept 20, 2021 Source: Covid19 India dashboardLockdowns have also not worked for Kerala during the second wave and this has prompted the state government to alter the guidelines frequently. The state’s daily cases continued an upward march, despite it being under a complete lockdown between May 6 and June 16, 2021. Seeing the poor results, the government introduced a four tier-based system where lockdowns with different intensities were implemented in high risk regions identified on the basis of the test positivity rates.

On August 4, the state implemented a triple lockdown system in wards with more than 10 cases per 1,000 people. Under this, the police and administration operated at three levels to stop the community spread: The first is the general containment strategy to keep the overall movement of the population to the minimum, the second is high surveillance in clusters where primary and secondary contacts of the infected persons are staying in quarantine and the third involves focused intervention on the households of the infected persons and well as those of their primary and secondary contacts.

At present, the state is identifying lockdown zones in areas where weekly infection population ratio is over 7 (number of COVID-19 cases reported in the week multiplied by 1,000 and divided by total population of the area).


Read more: COVID-19: Kerala needs to revisit approach

While experimenting with different kinds of lockdowns, the state government's primary focus has remained on vaccinating the people fast. Unlike the rest of India, Kerala decentralised its vaccination drive on August 11 for better reach. The government directed district collectors to coordinate with the health department and prepare ward-wise lists of unvaccinated senior citizens and administer them doses on priority.

Kerala has strong coordination between the local governments and civil society organisations and this decentralised approach was one of the reasons the state successfully fought the first wave. The benefits of this approach can also be seen this time around. By mid-September, the state had managed to administer the first dose to over 80 per cent of the population in Ernakulam, which had the highest 32,000 active cases on September 21, as per the state COVID-19 dashboard.

The state plans to vaccinate the entire adult population by September. “Full vaccination will happen only by the end of the year as the gaps between the two doses have to be maintained,” says Dileep Mavalankar, director, Indian Institute of Public Health, Gandhinagar. As Kerala is sprinting towards complete vaccination, it could face problems of vaccine hesitancy.

Sadanandan, though, feels the worst is over for the state and it is likely to come out of the current epidemic by October, provided a new variant does not emerge. His observation is backed by the infection rate (R value) of the state that has constantly remained below 1 (suggesting that an infected person passes the virus to only one individual) since September 4. This hints the state might have been able to break the spread of the virus.

The challenge now is to ensure that the Kerala surge does not spread and cause deadly waves elsewhere in the country. “In Mizoram, the R value has remained over 1 since August end and this is a cause of concern,” says Sinha.

This was first published in Down To Earth’s print edition (dated 1-15 October, 2021)

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