The Impact of First-Time SARS-CoV-2 Infection on Human Anelloviruses

Abstract

Members of the Anelloviridae family dominate the blood virome, emerging early in life. The anellome, representing the variety of anelloviruses within an individual, stabilizes by adulthood. Despite their supposedly commensal nature, elevated anellovirus concentrations under immunosuppressive treatment indicate an equilibrium controlled by immunity. Here, we investigated whether anelloviruses are sensitive to the immune activation that accompanies a secondary infection. As a model, we investigated 19 health care workers (HCWs) with initial SARS-CoV-2 infection, with blood sampling performed pre and post infection every 4 weeks in a 3-month-follow-up during the early 2020 COVID-19 pandemic. A concurrently followed control group (n = 27) remained SARS-CoV-2-negative. Serum anellovirus loads were measured using qPCR. A significant decrease in anellovirus load was found in the first weeks after SARS-CoV-2 infection, whereas anellovirus concentrations remained stable in the uninfected control group. A restored anellovirus load was seen approximately 10 weeks after SARS-CoV-2 infection. For five subjects, an in-time anellome analysis via Illumina sequencing could be performed. In three of the five HCWs, the anellome visibly changed during SARS-CoV-2 infection and returned to baseline in two of these cases. In conclusion, anellovirus loads in blood can temporarily decrease upon an acute secondary infection.

Genetic Characteristics of Anelloviruses Detected in Individual Viromes of Children with Acute Respiratory Infection Using the Metagenomic Approach

“…After the elimination of the main pathogen, AVs increase to their initial levels, and the anellome stabilizes. Similar observations in fluctuations of AV levels have been made in patients with COVID-19, where the anellovirus load significantly decreased in the first weeks of SARS-CoV-2 infection [51].…”

The Emerging Tool of the Human Anellovirome

“…Timmermann et al at the University of Amsterdam found a significant decrease in anellovirus load in the first weeks after SARS-CoV-2 infection among 20 unvaccinated healthcare workers, whereas anellovirus concentrations remained stable in the uninfected control group. It took about 10 weeks to restore the anellovirus load [ 7 ]. In Rome, Abbate et al with our research group at the National Institute for Infectious Diseases found higher TTV loads in 21 people with acute HIV infection (AHI) than in 13 healthy controls, but this was lower in 28 individuals chronically infected with HIV.…”