Preventive methods initiated by our government should not lose steam; rather it should gather more steam with the onset of the monsoon, writes Dr Abraham Ittyachen M, a professor of medicine.

Come monsoon Kerala may face new challenges in fight against COVID-19Image for representation
Voices Opinion Monday, April 13, 2020 - 12:25

"We have always held to the hope, the belief, the conviction that there is a better life, a better world, beyond the horizon." These are the words of Franklin D Roosevelt or FDR as he was widely known, former President of the United States, who led his country during some of its most challenging times. 

As Kerala comes to terms with its COVID-19 challenge, it is time to plan for the challenges that lie ahead, look beyond the horizon. And this is no time to be complacent. 

Kerala is unique in many ways. It has the best primary healthcare delivery system in India, comparable to those in the developing countries. And at a fraction of the cost of what it takes in the developed world. The resilience of Kerala’s healthcare system was proved to those in the state and the rest of the country during the Nipah outbreak in 2019. A sizeable chunk of Kerala’s budget is allocated to healthcare and education. But Kerala’s uniqueness is not without its challenges. Its population density is among the highest in India. And that too squeezed into a narrow strip of land between the Arabian Sea and the mountain regions of the Western Ghats. A significant population of Malayalees are expatriates. 

Infectious diseases and the monsoon 

Kerala’s health scenario is also different from the rest of the country.With a longer life span it has among the highest percentage of geriatric population in India. And this is reflected in the high prevalence of chronic age related diseases in the society. 

The incidence of infectious diseases also takes a unique pattern. A study done in Kolenchery Medical College and published in the year 2015 in ‘Tropical Doctor’, a leading international journal in tropical diseases clearly showed a predilection for infectious illnesses to rise parallel to the onset of the monsoon (May/June) and taper along with it (August/September). In this study, data pertaining to over 10,000 patients stretching over a period of ten years was analyzed (Ittyachen AM, Ramachandran R. Study of acute febrile illness: A 10-year descriptive study and a proposed algorithm from a tertiary care referral hospital in rural Kerala in southern India. Trop Doct. 2014 Dec 23. pii: 0049475514566264). Mortality rate was higher in those above 65. Air borne, water borne and vector borne diseases contributed to the majority of the cases, according to this study. 

A similar conclusion was also drawn in another study albeit a smaller one, a multi-centre study involving Kolenchery Medical College and Government Medical College, Trichur (Andrews MA, Ittyachen AM. Aetiology of acute febrile illness: a multicentre study from the province of Kerala in southern India. Trop Doct. 2018 Aug 20:49475518794572. doi: 10.1177/0049475518794572). 

The Government of Kerala has risen to the initial challenge and is doing a remarkable job in controlling the spread of the novel coronavirus. Probably there was tacit approval from the weather gods also. The main route of transmission of SARS CoV-1, the causative agent of SARS epidemic in 2003 was airborne. Regarding SARS CoV-2 the causative agent of COVID-19, the final verdict is not yet out though two recent studies from the USA conclude that respiratory spread is plausible; WHO has also expressed a similar view. The viability of this virus is rapidly lost at higher temperatures and higher relative humidity. Also it may become less virulent under these conditions. There are already studies supporting this hypothesis. This could explain why most countries in the tropical areas did not have any major community outbreak nor a surge in seriously ill patients to date. Fortunately, Kerala also has a similar weather pattern now. Then there is the question of the strain of the virus involved. Already there are reports of different strains of the virus appearing in literature. Hopefully ‘our virus’ would be a less virulent strain. 

But all this is going to change with the onset of the monsoon by May end/ June beginning. And this is where our horizon lies now. 

Migration during the monsoon 

A special mention must also be made of the academic summer break in America and Europe, stretching variedly from June to September. This is the time when Malayalees and tourists from these countries prefer to visit Kerala. America and Europe are now battling the coronavirus epidemic. So it is yet to be seen whether there will be migration of people from these countries during our monsoon. But there will certainly be a reverse migration from the Middle East, which is currently a hot spot for COVID-19. 

A high density of population with a high geriatric fraction entering the monsoon period, a period with a proven spike in infectious illnesses with morbidity and mortality in the elderly and at the same time welcoming our expatriate brethren; and tourists from the West who have come on holidays. One does not need to read between the lines to understand the unfolding scenario. And this is what we see over our horizon right now. 

Herd immunity a ray of hope

We are a free nation and each individual’s liberty is guarded zealously. Draconian measures like some of those in China are unthinkable in our society. Though the government had initiated a lockdown, it has not entirely turned out to be a ‘shut down’; shops are allowed to open with restrictions in place and limited travel is permitted. In epidemiological terms this may allow low level community spread thereby initiating a slow march towards hitting the ‘herd immunity threshold’. ‘Herd Immunity’ is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection either through previous infection or vaccination, thereby providing a measure of protection for individuals who are not immune to that particular disease. This is because when a large proportion of individuals in a community possess immunity to a particular disease, such people are unlikely to contribute to transmission of that disease. This breaks the chain of infection which ultimately stops or slows the rate of spread of the disease. As per data available in present literature the herd immunity needed to prevent community transmission of COVID-19 is around 60 to 70% which means around 60 to 70% of the population should develop immunity against the virus. 

Recent reports in the media of an increase in the number patients with fever and respiratory symptoms visiting hospitals allude to this. Herd immunity can be measured by testing for the presence of antibodies to SARS CoV-2 and media reports point to a move by the government to do this; to determine if community spread has occurred. Since vaccines are not expected any time in the foreseeable future, this route to containment of COVID-19 is also closed. And so that leaves us with ‘herd immunity’ turning out to be a significant determinant of community protection. 

If herd immunity offers us a ray of hope, the onset of summer in distant lands is surprisingly yet another. With the onset of summer, the ‘flu season’ comes to an end in America and hopefully all airborne infections including COVID – 19 will end. But if on the contrary, extra measures may be needed. There may have to be extra vigil at the entry points to the state, be it by road, rail or flight. Tourism especially from temperate zones may have to be stopped temporarily. The old, infirm, immunocompromised and the pregnant may have to be quarantined. And strong quarantine measures may have to be instituted for the impending surge in reverse migration from the Middle East, which is currently a hot spot of COVID-19. 

With proper long term planning, the scenario that is yet to unfold is still within our grasp. Preventive methods initiated by our government should not lose steam; rather it should gather more steam with the onset of the monsoon. Herein, also lies the duty of each citizen - rise to the occasion; ask yourselves what you can do to prevent the resurgence of this epidemic. A slow and grinding march but definitely a forward one towards hitting the ‘herd immunity threshold’, decreasing trends in infection in temperate lands along with restriction of travellers and expatriates from these lands and the Middle East, continued efforts by the government and health authorities along with citizen initiatives; all of this will go a long way in mitigating a resurgent epidemic during the monsoon season. Come what may, united we stand, even in the worst of scenarios, the horizon is still within our grasp. 

Dr Abraham Ittyachen M  is MD (General Medicine), IDCCM (Critical Care), PGDEPI-DL (Epidemiology) and Professor of Medicine M.O.S.C Medical College Kolenchery in Ernakulam District.