A new study found vegetarians and smokers have a reduced risk of COVID-19 infections, contradicting earlier findings that smokers had an increased risk of contracting the disease and suffering more serious complications.

The nationwide study, conducted by the Council of Scientific and Industrial Research (CSIR) of India, also found people with type O and A blood types are less vulnerable to the virus, while those who have type B or AB are at increased risk of illness from COVID-19.

According to The Hindu Business Line, the study involved over 10,000 participants and the Indian researchers said "smoking, vegetarianism, and having A or O blood type appeared to be protective." The scientists also found people who used private instead of public transportation also had a lower risk of getting COVID-19. These populations appeared to have a higher seropositivity, or antibody protection against the virus.

However, Dr. J. Taylor Hays, director of the Mayo Clinic's Nicotine Dependence Center, stated:

"As we know from the previous coronavirus outbreaks, smokers were more susceptible to infection and are more likely to get serious infection."

Hays noted smoking can also lead to behavioral risks such as hand-to-mouth contact, not wearing masks when they light up, and exhaling and inhaling deeply.