Deciphering factors linked with reduced SARS-CoV-2 susceptibility in the Swiss HIV Cohort Study. Journal of Infectious Diseases.
Abela et al. aimed to explore the epidemiology of SARS-CoV-2 waves in Switzerland from 2020–2021 among people with HIV (PWH) compared with the general Swiss population and determined the parameters associated with SARS-CoV-2 infection in both populations.
The author team analyzed SARS-CoV-2 polymerase chain reaction (PCR) test results, COVID-19–related hospitalizations, and deaths reported to the Swiss HIV Cohort Study between 1 January 2020 and 31 December 2021. Antibodies to SARS-CoV-2 and circulating human coronavirus (HCoV) were determined in prepandemic (2019) and pandemic (2020) biobanked plasma samples and compared with findings in HIV-negative individuals.
No HIV-1–related factors were associated with SARS-CoV-2 acquisition. High prepandemic HCoV antibodies were associated with a lower risk of subsequent SARS-CoV-2 infection and with higher SARS-CoV-2 antibody responses on infection. The authors observed a robust protective effect of smoking on SARS-CoV-2 infection risk (adjusted odds ratio, 0.46 [95% confidence interval, .38–.56]; P < .001), which occurred even in previous smokers and was highest for heavy smokers.
In conclusion, the study found that 2 unrelated factors affecting the respiratory milieu, namely prior HCoV infection and smoking, had strong protective effects against SARS-CoV-2 acquisition. The association between smoking and reduced SARS-CoV-2 infection risk has been reported in other studies but has not found wide acceptance. Future studies will be needed to unravel whether pathophysiologic effects, such as stimulation of innate defenses or down-regulation of angiotensin-converting enzyme 2 receptors, are involved in lower susceptibility to SARS-CoV-2. While the study observed a protective lower risk of SARS-CoV-2 acquisition in smokers, this should not be read to mean that smoking will prevent against the virus or severe disease.