By Sunil J. Wimalawansa –
The official reports on the prevalence and the number of deaths related to COVID-19 in tropical countries including Sri Lanka (excluding India) have been surprisingly low compared to most temperate countries. Let us explore some of the critical reasons for this significant discrepancy.
Why was the reported prevalence of COVID-19 low in Sri Lanka?
The reported prevalence of COVID-19 was spuriously low due to technical and biological reasons. Technical reasons include, (A) minute number of PCR testing that was carried out: less than 3% per million population, compared to industrialised countries and (B) the failure (the refusal) to carry out community testing in Sri Lanka, until mid-October. There is no evidence that Sri Lanka had a COVID-19 free period since April 2020: the lack of reported cases was due to conducting too few PCR tests in and out of hospitals and thus, the failure of detection. This should not have been a reason to celebrate.
Why were the reported deaths due to COVID-19 was low in Southeast Asian countries?
The biological explanation for the exceptionally low number of severe complications (i.e., needing ICU care) and deaths reported was due to virtually no persons in tropical countries such as Sri Lanka suffer from “severe” vitamin D deficiency (i.e., serum 25(OH)D concentration, less than 10 ng/mL). Equatorial countries have round-the-year sunshine, and people are getting exposed to sunlight whether they like it or not, which is enough to maintain the innate immune functions. Despite the advantage of having 300+ days of sunshine each year, very few people opting to get exposed to sunlight that would generate vitamin D through their skins and the government failed exploited it. During the current COVID era, this negative cultural trend is unfortunate.
How to achieve sufficient vitamin D levels?
Despite having plentiful sunshine, no administration in tropical countries provides public health guidance using the mass media on safe sun exposure at the individual or population level. Simple instruction such as daily sun exposure to a third of the bare skin surfaces for at least 30 minutes, between 10.30 AM and 1.30 PM (i.e., when person’s shadow is shorter than the height), wearing a brimmed hat to protect the face and sunglasses or similar device to shielding eyes can make the difference of getting sick from COVID or staying healthy.
The physiological needs of vitamin D during the COVID era for an adult is approximately 5,000 IU/day; this is the necessary daily maintenance dose. However, those who are deficient and insufficient need a larger upfront dose to saturate the body stores before rising serum 25(OH)D concentration. In the absence of such, it might take months to reach a healthy blood level, which could be too late for some. Depending on the skin colour, sun exposure could generate between 800 and 2,500 IU of vitamin D per day. Over time, daily exposure can naturally generate vitamin D, enough to maintain the function of the immune system to prevent complications and deaths from COVID-19.
Low vitamin D increases the risks of COVID:
Globally, the vast majority of those who developed severe complications, requiring intensive care unit admission or died from COVID-19 had severe hypovitaminosis D. Adequate vitamin D levels are essential for maintaining optimal immunity against invading pathogens, such as COVID-19.
There are a few reasons why low death rates reported in tropical countries. Firstly, performing too few PCR testing and not testing the sick, elders, dying, and deceased persons. Less testing means less detection. From mid-October 2020, PCR testing was expanded in Sri Lanka and extended to test the dying and dead persons. Secondly, although the population serum vitamin D levels are low, are still adequate because of inevitable sun exposure to generate vitamin D to prevent severe complications and deaths from COVID-19. It is possible that near 100% BCG vaccine coverage in the country is also having a low degree of protection against COVID-19. The low reported deaths were mostly due to technical failures: nothing to do with any intervention−curfew or healthcare delivery. The vast majority of those who died from COVID are either had chronic diseases (i.e., comorbidities) and/or advanced age.
False propaganda and draconian measures harmed the trust and the control of COVID-19:
Contrary to claims by spokes-persons, the community spread of COVID-19 has been present continuously since April 2020. Moreover, there is no scientific evidence of altered virulence or mutation of the virus of COVID-19 in Sri Lanka or the current second wave is due to a different strain or a new virus. However, this can happen in months to come, especially with the insane decision to open the country to the influx of high-risk tourists with potential new strains of COVID-19. The cost of taking care of them is likely to be more than ten times the frugal income generated from this group of tourists: a big mistake with no benefit to the country. Over the past 20 years, it has been a routine practice for successive governments to divert public attention from its failures using tactical deployments, such as cricket; the COVID-19 mismanagement is not an exemption.
Since mid-October, the number of PCR positive persons has been increasing due to, (A) mounting community spread with multiple clusters of infections spreading across all 25 districts and (B) increased PCR testing from about 500 tests to 10,000 per day. This approximate, twenty-fold increase of PCR testing began in October, was conducted mostly in high-risk communities (not random community testing). Therefore, it is not astounding a higher number of detection. Nevertheless, the rate of detection has not changed significantly.
Re-deployment of curfew in October 2020 was a mistake:
The decision to impose curfew in mid-October 2020, was based on a sudden increase of the total ‘number’ of positive PCR tests, not on the “rate“ of PCR positivity ⎯ the true incidence of COVID-19 in the country. This mistaken interpretation led to publicising an abysmal picture via the mass media, which used as an excuse to re-introduce, detrimental and worthless curfew. Despite this, the COVID-task force is still discussing imposing a country-wide curfew yet again: if allowed by the president, it will ruin the country’s economy.
The current mundane approaches are like, holding the “tiger’s tail” with reactive responses with little or no proactive actions. Such is unlikely to bring the COVID-19 under control soon. Meanwhile, it is wiser to use both rapid antigen and PCR testing together to reduce the significant numbers of false positives and negative results, in conjunction with antibody testing as appropriate.
How should PCR positive rates be calculated and reported?
For the benefit of readers’, the following is an example of how the “rate” of PCR should be calculated, interpreted, and reported. The comparison given below is based on a hypothetical, estimated average in months, June and October, and is intended as an example:
June 2020: On average, 500 PCR tests/day were performed, and the average detection of positive cases was ~10 per day. Thus, the PCR positivity rate in June: 10/500 x 100 = 2% (during this period, no community PCR testing was conducted).
October 2020: On average, 10,000, PCT tests were performed daily, following the so-called Minuwangoda cluster. This sudden increase led to average detection of cases to 300 per day. So, the rate of PCR positivity in October was: 300/10,000 x 100 = 3.0%.
Thus, the rate of increase was from 2% to 3%, which is fully accountable for the increased numbers of PCR testing in high-risk populations. Despite denials by spokespersons, it was a typical community spread and not exponential dissemination of COVID-19. The administration should admit the ongoing community spread and failures of COVID- control, allowing deployment of different strategies to manage the epidemic: keep arresting people and glorification is not the way forward. The current approach is failing.
The incidence data should express as a ratio (rate) or as a percentage. However, for global and local comparison, the deaths due to COVID-19 should be reported as per million population. Such would allow fair comparisons and objective assessment on whether there is (or not) an exponential growth or outbreaks of COVID-19 (R0), without being emotional or political. Less than double the rate reported was due to increased testing in high-risk communities and does not reflect an exponential spread of COVID in Sri Lanka, requiring draconian actions. Fearmongering to control the public is not be the way forward.
Misguided policies, COVID-19 community clusters, and stagnant economy:
When the numbers of PCR tests increased in community clusters, a higher number of PCR positive persons are detected. The opposite happened between April and September 2020 in Sri Lanka when no community PCR testing was conducted. Consequently, a falsely low number of cases (i.e., less than, 5% of the infected) were detected (glorified) and reported to the World Health Organization. Faulty reporting led to a false sense of security and misguided actions that led to the second wave. Together with the desire to conduct a general election, demanded relaxation of otherwise essential public health restrictions that further enhanced the community spread, affecting all 25 districts in Sri Lanka.
Sequences of misjudgements and too rapid relaxation of public health measures allowed the development of multiple COVID-19 clusters among high-risk community groups across the country. Well over 90% of people identified as PCR positive are asymptomatic. However, just because a person tested positive, neither means they are infected with the COVID-19 virus nor currently infectious. Moreover, depending on the quality of PCR kits used, a significant number are known to be false positive.
The public assumes that the administration is learning from mistakes and missed opportunities for better management of COVID for preventing future economic disasters. However, this does not seem to be the case. The published global community infection data suggests, on average, 20-times more infected people present in the community compared to PCR positive persons identified in hospitals and quarantine centres. On this basis, it is estimated that currently there are over 600,000 PCR positive persons in Sri Lanka, vast majority undetected and do not require medical attention; thus, there is no reason to be panic. Therefore, the daily detection of a higher number of PCR positive persons is not surprising.
*Professor Sunil J. Wimalawansa, MD, Ph.D., MBA, DSc.