The following is a summary of “Human Cytomegalovirus Infection of Epithelial Cells Increases SARS-CoV-2 Superinfection by Upregulating the ACE2 Receptor,” published in the February 2023 issue of Infectious Diseases by Perera, et al.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused significant morbidity and mortality globally since its emergence in late 2019. In addition, a recent study found that prior infection with human cytomegalovirus (HCMV) significantly increased the severity of SARS-CoV-2 infection in vitro. 

HCMV is a common herpesvirus carried by 40% to 100% of the population and can reactivate in the lungs under inflammatory conditions such as those caused by SARS-CoV-2. The study showed that HCMV infection increases the expression of ACE2, the receptor for SARS-CoV-2, in both endothelial and epithelial cells. Furthermore, the findings suggested that HCMV reactivation in the lungs of healthy carriers could worsen SARS-CoV-2 infection and the resulting COVID-19 symptoms.

The researchers also suggested that the effect could contribute to the differences in disease severity in ethnic minorities and those with lower socioeconomic status due to their higher CMV seroprevalence. A further clinical investigation was warranted to determine whether HCMV infection influences the pathogenesis of SARS-CoV-2. The study highlighted the need for a better understanding of the interplay between various viral infections and their potential impact on the severity of COVID-19.

Reference: academic.oup.com/jid/article/227/4/543/6835053