Rather, the findings can lead to exploration of "immune training with possibilities of microbiome therapies", said Dr Shekhar Mande, Director General, Council of Scientific and Industrial Research (CSIR).
"It is, therefore, perplexing to note the positive correlation of sanitation parameters with the Covid-19 CFR," it said.
Countries with poor hygiene and sanitation and low quality of water supply seem to have had lower COVID-19 Fatality Rates (CFR) compared to richer countries which do well on these parameters, Indian researchers have found. But they also cautioned that it does not mean that poor hygienic conditions are desirable. Rather, the findings can lead to exploration of “immune training with possibilities of microbiome therapies”, said Dr Shekhar Mande, Director General, Council of Scientific and Industrial Research (CSIR).
Researchers from the National Centre for Cell Sciences (NCCS) and Chennai Mathematical Institute conducted the study titled `The mortality due to COVID-19 in different nations is associated with the demographic character of nations and the prevalence of auto-immunity’. The paper, published in Medrxiv, has not been peer-reviewed. They studied — across 106 countries — 25 to 30 parameters including demography, prevalence of communicable and non-communicable diseases, BCG vaccination, sanitation and COVID-19 deaths per million.
“Per million population (deaths) number appears to be high in countries that are richer and having high GDP and (in) countries with low GDP, less number of people are dying, which is very paradoxical,” said Mande, who is a co-author of the research paper. The percentage of people above the age of 65, who are believed to be at greater risk if they contract COVID-19, is significantly higher in high-GDP countries, Mande said. They also found higher auto-immune diseases prevalence in richer countries. Auto-immune diseases such as multiple sclerosis, type 1 diabetes mellitus, psoriasis, rheumatoid arthritis, asthma “are prevalent in richer countries because they have very good sanitation such as hand-wash, basic drinking water, no open defecation and that actually led to more auto-immune disease parameters in higher GDP countries”, Mande said.
“So all these parameters (demography, sanitation and prevalence of auto-immune diseases) combined together account for the fact that countries with higher GDP have higher death per million (due to COVID-19) than countries with lower GDP,” he said. The research paper noted that poor hygiene practises and lack of sanitation are known to be responsible for the higher communicable disease burden in the low GDP countries1. “It is, therefore, reasonable to expect that parameters describing safe sanitation and safe drinking water to be correlated negatively with the Covid-19 deaths. “Surprisingly we find a contrary observation, where different sanitation parameters are correlated positively with the Covid-19 outcome,” the study said. “It is, therefore, perplexing to note the positive correlation of sanitation parameters with the Covid-19 CFR,” it said.
“Countries which are poor and have less hygiene, they get more infectious diseases such as TB, malaria and countries which are rich with better hygiene conditions, there are no such diseases in abundance, but exactly opposite happened in our study (regarding COVID-19 mortality),” Mande said. Although the study provided a possible explanation based on sanitation practices on the CFR difference between economically stronger and weaker countries, it did not mean the researchers favoured weaker hygiene practices for handling future pandemics, he stressed. “Rather this analysis opens up avenues to consider immune training with possibilities of microbiome therapies to supplement improved hygiene and sanitation practices,” said Mande.