In the early days of Covid, when the fatality rate in Europe send chills down the spines of Indians, there were frequently forwarded humorous WhatsApp forwards meant to cheer up people which went somewhat along the lines of, “Coronavirus will itself die in India due to our air and water pollution.” That was meant to be a joke.
However as Covid-19 spread across India, we noticed a stark difference in fatality rate compared to Europe and America. While the reason behind this left scientists baffled, with various schools of thought emerging, a new study has found that countries with poor hygiene and sanitation and low-quality water have a lower Covid-19 fatality rate as compared to richer countries where sanitation quality is high. Until now, scientists have wondered at the higher prevalence of infection and deaths from Covid-19 in richer countries as opposed to poorer ones.
While the findings indicate that the poorer the water sanitation in a country, the lower the Covid-19 deaths per million, the study has strongly advised against pursuing weak hygiene as a disease coping mechanism. Demography improved hygiene, and a higher incidence of autoimmune disorders correlated positively with Covid-19 mortality and were among the most plausible factors to explain it as compared to GDP of the countries, said Dr. Shekhar Mande, director-general, Council of Scientific and Industrial Research (CSIR).
“Researchers from Pune’s National Centre for Cell Science (NCCS) and Chennai Mathematical Institute conducted a statistical analysis and examined more than 25 to 30 parameters, including water, sanitation, and Covid-19 deaths patients per million in 106 countries,” Mande told The Indian Express.
“One of the primary manifestations of Covid-19 has been a severe autoimmune reaction in the later phase of the disease. Among the reasons for rising prevalence in autoimmune disorders in western countries is proposed to be related to the ‘hygiene hypothesis’,” said Mande, who is the co-author of the study ‘The mortality due to Covid-19 in different nations is associated with the demographic character of nations and the prevalence of autoimmunity’, published on MedRxiv.
Paradoxically, better sanitation leads to poor “immune training” and this hypothesis postulates that exposure to pathogens early in life protects people from allergic diseases later in life. Better hygiene practices could lower a person’s immunity and make him or her susceptible to autoimmune diseases. Improvement in hygiene practices such as better sanitation, availability of safe drinking water, hand washing facilities, and others reduces the impact of communicable diseases. On the contrary, such a reduction to exposure to infectious agents might be related to a higher prevalence of autoimmune disorders, researchers have noted in the paper.
First world countries have a significantly better quality of living and are superior on almost every health parameter. Though that ensures timely and better treatment, it has seen to reduce the natural immune response of the body given its lack of exposure to pathogens.
Researchers Bithika Chatterjee from NCCS and Rajeeva Laxman Karandikar from Chennai Mathematical Institute examined developmental parameters like demography, the prevalence of communicable and non-communicable diseases, BCG vaccination status, sanitation, and Covid-19 deaths per million in the 106 countries. Researchers ran multivariate linear regression models to discover that the incidence of communicable diseases correlated negatively while demography, improved hygiene and higher incidence of autoimmune disorders correlated positively with Covid-19 mortality.
“Statistical evidence should give a head start to investigate the role of hyperimmune reaction on Covid-19 susceptibility at the individual patient’s level and this analysis opens up avenues to consider immune training with the possibility of microbiome therapies to supplement improved hygiene and sanitation practices,” Mande said.
The findings have been consistent in India. The research revealed that within India, Bihar, one of the poorest States on socio-economic parameters, kept the death rate at 0.5 percent, i.e. one third the national average. Bihar is not alone with a low CFR. Kerala and Assam, with a rate of 0.4, Telangana 0.5, and Jharkhand and Chhattisgarh at 0.9 have CFR less than one. However, fairly better States in terms of standard of living, economy, and hygiene, including Maharashtra, Gujarat, and Punjab, have CFR values of 2 or higher.
Though this is a sigh of relief for poorer States with fragile health infrastructure, the study should not be used as an excuse for hindrance in the development of better State healthcare facilities.