Cigarette smoking is linked to rising risk of viral infection, including a coronavirus and respiratory illness, according to the findings of a study published recently in the Nicotine and Tobacco Research Journal. The study also supported urgent recommendations for doctors to help patients quit smoking as a way of countering COVID-19.

Smokers have a 12 per cent high risk of laboratory-confirmed viral infection and a 48 per cent increased chance of being diagnosed with respiratory illnesses, according to the researchers from the University of California (UC) - Davis found. 

The study's lead author, Melanie Dove, from UC Davis Past research has shown that smoking increases the risk of COVID-19 disease severity, but the risk of infection has been less clear.

Dove further added that the study findings reveal that smokers have an increased risk of viral infection, including coronavirus and respiratory illness. 

The data from the British Cold Study (BCS), 1986–1989 challenge research that exposed 399 healthy adults to 1 of 5 "common cold" viruses, was re-analysed by the researchers. The common coronavirus (coronavirus 229E) that preceded the novel coronavirus (SARS-CoV-2 virus), which causes COVID-19 disease, was also included in it. 

Overall and coronavirus-specific unadjusted and adjusted relative risks for current smokers were calculated by the team for each outcome, testing whether each association was modified by the type of respiratory virus. The study found that current smokers had an increased risk of respiratory viral infection and illness without any significant difference across the types of viruses.