The COVID-19 situation will get even grimmer for Kerala in the next 100 days, according to a projection report prepared by Health Department officials. The report projects that 18,000 people coming from outside and their contacts will test positive while more than 150 deaths can be expected from this group by the end of August.
The report was presented at a high-level meeting attended by Chief Minister Pinarayi Vijayan and Health Minister KK Shailaja last Friday.
“At least one in 2,000 people from the high contact group of people returning will be affected by COVID-19 (sentinel, augmented and surveillance data) and there are 2 lakh people in this group health workers of various categories, police, volunteers and people working in the distribution system, etc). So the total infections in this group is 100,” states the report.
Manoj Kadambad of Malayala Manorama daily has reported that, based on the projections, the number of COVID-19 patients and deaths will see a surge in the state for the next three months.
The projection report comes up with some key assumptions on the spread of COVID-19 in the state. It states that 0.75% of those infected will be presented with clinical symptoms in healthy groups and will be captured by the system. 5% infected will be presented with clinical symptoms in vulnerable groups and will be captured by the system.
The report says that with an estimated highest incidence of infection, the epidemic will stop in six months with 2 lakh infections. However, only 2% of these people will be reaching hospitals for admission, the report concludes that around 23,000 cases will be detected. The report however makes no mention of why only 2% of people will require hospitalisation and when this six month period ends.
Report gives different scenarios
The report argues that given the state’s strong public health intervention, the Reproduction number or R0 (the average or expected number of people that an infected person could spread the virus to in her ‘infected’ period) would be less than 1.5.
It then projects four scenarios based on differ R0 values with 1.15 being the lowest and 1.45 being the highest. If the R0 is 1.45, there would be 444 infected people in the community on June 30. This number increases more than four-fold by July 31 to 2095. However, in a month’s time on August 31, the report says that with R0 at 1.45, the number of COVID-19 cases in Kerala will increase by more than 300% to 8974 overall infected people in the community. (These are people in whom the infection will be detected, most others will be asypmtomatic).
By September 30, there will overall be 25,403 people infected in the community. However, this projected figure stays the same a month later. There is no explanation for why the number of infected stays the same.
The report notes that with an R0 of 1.45, the “epidemic will stop six months with 2 lakh infections”. However, the total number of detections will be around 23,000. In other words, while only 23,000 individuals would have been detected as positive for the coronavirus by the state, the actual number of infections will be far higher - at 2 lakh.
Gautam Menon, professor of physics and biology at Ashoka University explained to TNM, “The smaller the value of R, the more delayed the peak will be and the lower its height at the maximum. The higher R0 will mean that herd-immunity through infection is reached faster.”
He, however, flagged some issues in Kerala’s report. “The numbers seem too small. If Kerala's population is 30 million (300 lakhs) approximately, one would expect herd immunity when about 60% of the population has been infected, This is assuming that R is around 2.5. This would be then about 18 million or 180 lakhs. They assume a much smaller value of R, of about 1.15 - 1.45. If we take 1.45, the fraction of the population required to catch the infection is at least 30%. (And this is an underestimate). Even at 30%, the fraction of the population that will be infected is 9 million or 90 lakhs for the herd immunity threshold. Their numbers are much smaller.”
Gautam also explains that the report assumes that only high-contact people are being infected, while others are protected. “If one does this, then their numbers make sense. 30% of 2 lakhs is 60,000. But then I don't understand their slide for cumulative infections for R = 1.45 which finds 2 lakh infections.”
Infrastructure
As far as Kerala’s infrastructure goes to handle the number of positive patients, the report notes that there are overall 1.27 lakh beds in government and private hospitals. In case of severe patients, the state has over 8000 beds, and over 2200 ventilators in both government and private hospitals.
So wil Kerala’s health infrastructure be able to handle the cases?
With an R0 of 1.5, and assuming that only 2% of cases require hospitalisation, and with an average hospital stay of 10 days, the report concludes that “infrastructure will be adequate for such situations”. It also notes that Kerala will see the epidemic’s peak when there are 1000 hospitalisations per day.
Strategies to reduce caseload
The report gives three broad strategies to reduce the caseload. To begin with, reduce the reproduction number, the state will have to ensure strict quarantine, test persons, carry out active contact tracing,and break the chain by physical distancing and reverse quarantine (protecting the vulnerable population). To reduce the severity of infections, the state will have to ensure reverse quarantine and the early diagnosis and treatment of the disease. To reduce hospital stay, the report says Kerala will have to adhere to ICMR’s present strategy of discharging patients (uncomplicated cases) after 10 days.