An Indian study has found that the SARS-CoV-2 virus nearly spares smokers and people with 'O' blood group. The serosurvey conducted by the Indian Council for Scientific and Industrial Research (CSIR) also found that vegetarians also have less sero-positivity than the rest of the population.
The pan-India serosurvey studied the presence of antibodies against SARS-CoV-2 in people. One of the authors of the study said the paper was recently peer-reviewed.
While smokers and vegetarians had lower sero-positivity, those with blood group 'O' were found to be less vulnerable to the disease, the Press Trust of India (PTI) reported, citing the study.
Similar Findings in Other Countries
Interestingly, the findings of the survey also corroborate observations made in countries including the United States with regard to the lower percentage of smokers being infected severely with the coronavirus.
The Indian survey was done by a team of 140 doctors and scientists and it reviewed more than 10,000 voluntarily participants. The most interesting finding was that though COVID-19 is a respiratory disease, smokers tend to be less affected by it. The inference made in the study is that smoking increases the mucous production, resulting in the creation of a certain resistance against the virus.
"Smoking is known to be severely detrimental to health and associated with multiple diseases and this observation should not be taken to be an endorsement, especially given that the association is not proved to be causal," the study says. It, however, cautions people not to make assumptions but wait for further studies.
The study also says that vegetarian food, which is rich in fiber, also gives the body more immunity.
Regarding the blood groups, the survey says that while people with group 'O' are less vulnerable, those with 'B' and 'AB' are at a higher risk.
The report also cites earlier findings in France, Italy, China and the US regarding the connection between smoking and coronavirus infection. As per a study by Centers for Disease Control and Prevention (CDC), only 1.3 percent of survey participants were smokers while data showed that 14 percent of Americans were smokers.
Another academic paper that looked at various studies in UK, China, France and the US also found that the ratio of smokers among hospitalized patients was far lower than that of the general population. For example in the UK, the national rate of smoking is 14 percent but smokers constituted only five percent of the hospitalized patients.
In France, the percentage of smokers among Covid-related hospitalization was a lowly 7 percent while the national average of smokers was above 30 percent.
The study comes at a time when India is grappling with a surge in coronavirus cases and a shortage of hospital beds and oxygen.