Can India be an outlier in the Covid-19 spread? The | Opinion – analysis
Coronavirus disease (Covid-19) first appeared in the Wuhan district of China’s Hubei province in early December 2019. China reported the first case on January 7, 2020, and this sparked variable interest. Worldwide, with most countries initially ignoring new infection Fortunately, Indian health authorities detected the danger, in large part because the country has always been alert to new infections. The group of scientific experts from the Indian Council of Medical Research (ICMR) was immediately activated and the first laboratory-confirmed case was identified at ICMR’s National Institute of Virology (NIV), Pune, sometime in late January.
A look at the Covid global meter shows that there is a surprising variation in mortality rates between countries, ranging from 0.2% to 15% depending on age, smoking, and pre-existing comorbidities. It may be too early to tell, but overall, countries in the northern hemisphere have faced the brunt, and those in the southern hemisphere (and those located near the equator) have so far escaped a high number of infections.
Three factors appear to be playing a role in the lowest numbers observed in India, with almost zero occurrence of severe Covid-19 cases (so far). First, broad-based immunity in the population due to extensive microbial load. The Indian population has been exposed to a wide variety of pathogens, including bacteria, parasites, and viruses, leading to the generation of extensive specific memory T cells in the system, ready to attack additional foreign invaders.
For example, the top three killers of tuberculosis, HIV, and malaria have affected India, Africa, and several countries in the southern hemisphere much more than European and North American nations. In the context of the CoV-2 coronavirus, the beneficial role of chloroquine and hydroxychloroquine has been widely discussed and debated, while this drug has already been widely used at community level in India; This can also be beneficial.
Second, epigenetic factors that include environmental and dietary habits can also play a beneficial role for countries like India; There is already a lot of literature available in Ayurveda and other Indian systems of medicine on the definitive beneficial effects of Indian spices for boosting immunity.
Third, and most importantly, is the possible role of immune response genes in the Indian population. These genes are collectively referred to as comprising the human leukocyte antigen system, or simply HLA genes. Their main biological function is to present foreign invading antigens to the immune system, since T cells, which act as body soldiers, come into play only when pathogens are presented to them more formally in association with HLA genes. In other words, the pathogen must first bind to the compounds created by the HLA genes before T cells attack it. If the body does not produce such compounds, then T cells are ineffective. As a consequence of the microbial load, the Indian population has a high genetic diversity of HLA, much more extensive than the Caucasian populations. In fact, the author’s studies at the All India Institute of Medical Sciences, New Delhi, for several decades revealed the presence of several novel HLA genes and their alleles in the Indian population, most of which do not occur in other ethnic groups. . Such HLA genetic diversity could affect viral fitness.
The question then becomes: why does genetic variation in HLA genes play a role in Covid-19 progression? One clue comes from previous studies in related viral diseases: Certain genetic variants of the HLA system provide protection against such viruses, while others increase genetic susceptibility to them. Another indirect source of evidence comes from recent clinical studies of Covid-19 that showed that rapid T-cell response appears to be crucial for recovery of Covid-19, and reduction of functional diversity of T-cells in peripheral blood. could predict the progression of Covid-19.
The big question is: does this give Indians a better chance at fighting the virus effectively? From the epidemiological data so far, it appears so (although much more extensive research is required). However, it is important for us to keep viral loads under control and below threshold levels. In this context, the complete blockade announced by the government is very timely and most desirable. It is imperative that the virus replication cycle be interrupted as soon as possible before it reaches numbers that may be difficult to counter.
To this end, the images of crowds gathering in various places, whether to buy panic or interstate movements, are disturbing. They could jeopardize all efforts and mitigate any natural advantage we enjoy.
The State must act quickly to enforce the blockade, including by force if necessary. India may be the outlier in the fight against coronavirus infection and succeed in keeping overall numbers lower than the rest of the world with minimal deaths.
Narinder Kumar Mehra is National President of ICMR and former Dean of the Institute of Medical Sciences of India, New Delhi.
The opinions expressed are personal.