AABB22: New Findings Confirm Minimal Risk of Transfusion-Transmission of SARS-CoV2

There is minimal risk of transfusion-transmission SARS-CoV2, according to new data presented during the Plenary Oral Abstract Session at the 2022 Virtual Meeting. Rachael Jackman, PhD, from Vitalant Research Institute, who presented the data, said these findings support the current policy not to screen the blood supply for SARS-CoV2.

Jackman and her colleagues’ study was conducted using a mouse model, exposing highly susceptible cell lines to the highest viral load plasma found among SARS-CoV2 RNA+ donors. The mice were exposed to titrated doses of lab-cultivated SARS-CoV2 intranasally, intravenously or intraperitoneally. This study design was intended to evaluate the relative risk of infection through different exposure routes. Following exposure, the mice were monitored for SARS-CoV2 RNA in oropharyngeal swabs and peripheral blood, weight loss, visually apparent symptoms of disease, or mortality. 

The researchers observed no cytopathic effect in any of the mice. In addition, SARS-CoV2 RNA was not detected in any of the culture supernatants following inoculation with any of the RNA+ plasma samples. The researchers found the mice were highly susceptible to infection via intranasal and intraperitoneal exposure, with weight loss, symptomatic disease, RNAemia, and death observed at doses as low as 102 PFU. In contrast, intravenous exposure required higher doses for infection, with weight loss, symptomatic disease or mortality observed significantly fewer mice in this category. SARS-CoV2 RNA was detected in the blood of some mice who received intravenous exposure in the absence of other symptoms. 

Jackman said the findings indicate that either the SARS-CoV2 RNA circulating in donors’ blood may not be a replication-competent virus, or the levels of virus may be too low to pose an infectious threat. The findings also indicate that an intravenous route presents a low-risk portal of entry for SARS-CoV-2. 

Jackman said her study confirms the current policies not to screen all blood donations for SARS-CoV-2. “Considering the low levels of virus with the low risk of infection through an intravenous exposure, the findings suggest a minimal risk of SARS-CoV-2 transfusion transmission,” she said.