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COVID-19 in India: Are Biological and Environmental Factors Helping to Stem the Incidence and Severity?

Covid-19

The ongoing Corona virus (COVID-19) pandemic has witnessed global political responses of unimaginable proportions. Many nations have implemented lockdowns that involve mandating citizens not to leave their residences for non-essential work. The Indian government has taken appropriate and commendable steps to curtail the community spread of COVID-19. While this may be extremely beneficial, this perspective discusses the other reasons why COVID-19 may have a lesser impact on India. A few leading medical and biotechnology researchers analyzes the current pattern of SARS-CoV-2 transmission, testing, and mortality in India with an emphasis on the importance of mortality as a marker of the clinical relevance of COVID-19 disease. They have also analyzes the environmental and biological factors which may lessen the impact of COVID-19 in India presenting views on cross-immunity, innate immune responses, ACE polymorphism, and viral genetic mutations.

In their research paper, these medical ad biotechnology experts have shared the symptoms of COVID-19 range from mild to severe, which also include mainly fever, cough, and respiratory distress. Severe cases with pneumonia and hypoxemia result in considerable mortality. Older individuals with pre-existing chronic health condition shave a higher risk of developing severe complications after SARS-CoV2 infection.

COVID-19 has emerged as a pandemic of respiratory illness ever since the first cases appeared in Wuhan, China, in December 2019 Currently, it has spread to 203 countries/territories worldwide, with more than 920,000 infected cases and over 46,000 casualties (www.worldometers.info/coronavirus/). This ongoing pandemic has witnessed global political responses of unimaginable proportions. Many nations have implemented lockdowns that involve mandating citizens not to leave their residences for nonessential work. The rules of lockdown vary from country to country. The Indian Prime Minister announced a nation-wide lockdown from the midnight of 24th March 2020. Only essential services would be functioning and government services apart from health, law and order, banking, power and a few others have been suspended altogether. While the response by the Indian government both at the central and state levels has been commendable and timely given the global COVID-19 crisis, we deliberate some of the other reasons why the authors believe COVID-19 may have a lesser impact on India.

  1. Low incidence of COVID-19 in India – The world’s second-most populous country lies around the 40th rank among nations for the number of diagnosed COVID-19 cases (www.worldometers.info/coronavirus/). The first case of COVID-19 was detected in India in the southern state of Kerala on 30th January 2020 and was a medical student who had returned from Wuhan. Two other cases, also medical students back from Wuhan soon surfaced from Kerala (https://weather.com/enIN/india/news/news/2020-02-14-kerala-defeats-corona virus-indias-three-covid-19-patients-successfully). The Indian government implemented thermal screening of inbound international air-travelers.
  2. Environmental and Demographic factors – The population density of India is 414 persons/km2 , which is higher than the six countries with maximum COVID19 cases. Such a finding is a paradox as countries with higher densities and people staying closer to each other are theoretically at a higher risk of contracting communicable diseases transmitted by fomites or aerosols. Similarly, the examples of South Korea (517 persons/km2 ) and Japan (333 persons/km2 ), which have a relatively lower incidence of COVID-19 and a higher population density, support this curious case. Trying to explain this paradox would require further research. In the Köppen classification of climatic zones of the world, both Wuhan, the apparent epicenter of the pandemic and most of Italy are categorized as type C (mild temperate) whereas much of India has either a dry (type B) or tropical climate (type A). However, this again raises queries on why Iran having a dry desert climate (type B) bore the brunt of COVID-19 cases. It has been suggested that high temperatures and high relative humidity levels significantly reduce SARS-CoV-2 transmission. It may be fortuitous for India that as it enters the weeks deemed to mark its entry into phase 3 of the epidemic, the climate over large portions of the country is taking a turn for this same high temperature, high humidity state.

Another vital aspect of COVID-19 is mortality in diagnosed cases. Mortality is the statistic that is most relevant for developing nations such as India. Acute viral illnesses as well as acute infections due to any pathogenic agent, are prevalent in India, owing to dismal standards of hygiene, especially among a large section of its population which lives below the poverty line. An exact number cannot be ascribed to the incidence of viral infections, because of the sheer diversity of such infections ranging from respiratory viral infections (influenza, rhinovirus, adenovirus, coronavirus, etc.) to several arthropod-borne viral fever syndromes. The diagnostic facilities are nonexistent in the periphery, and the majority of these infections may be subclinical or may present with atypical manifestations. An idea can be obtained from the data of the Integrated Disease Surveillance Programme (IDSP) of the Ministry of Health and Family Welfare (MoHFW) of the government of India. During 2017, the IDSP reported 1683 disease outbreaks in India, of which 71% were due to viral pathogens. The authors, in their clinical practice, also treat patients regularly who present with classic symptoms of viral respiratory disease. Sometimes, the same patient with comorbidities such as COPD visiting multiple times in a year. Whereas such patients in affluent nations would be subjected to additional testing and probably annual influenza vaccination, such measures are mostly non-existent in the Indian scenario, apart from a few of the apex centers. The majority of such patients with fever, upper and lower respiratory tract symptoms, bodyache and headache may either not turn up at clinics, dismissing their symptoms as another bout of viral fever and resorting to home remedies, or even in case they present to a trained practitioner, supportive management is at best done. Even drugs such as oseltamivir are scarcely used in routine practice. Even with community transmission of the virus (phase 3 of the epidemic), most cases may turn out to be subclinical and mild. In the end, mortality and not morbidity is the statistic that matters.

Conclusion: The different restrictive measures adopted by the central and the state governments in India like visa and travel restrictions, home isolation and quarantine, and finally nation-wide lockdown are classical methods of prevention of the community spread of SARS-CoV-2. These methods must have played a role in limiting the effect of this pandemic on the Indian population. However, the paper-presenters strongly feel that various biological and environmental factors have also contributed significantly to this process, which may result in COVID-19 in India behaving more mildly in contrast to its global effects. The careful analysis of such biological factors will certainly open new avenues to combat outbreaks of novel viruses, through research on cross-immunity, immuno-modulation and perhaps lifestyle management and dietary manipulations.

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