Asymptomatic SARS-CoV-2 infection following first dose mRNA-1273 COVID-19 vaccine in a veterans affairs long term care facility.

An outbreak of SARS-CoV-2 involving four residents of a United States Veterans Affairs long term care facility occurred following administration of the first dose of the mRNA-1273 vaccine (Moderna) to thirty out of 33 residents. Three out of 4 positive cases were partially vaccinated and remained asymptomatic. One of 2 partially vaccinated patients who were tested for anti-spike protein antibodies had detectable levels at the time of diagnosis. The mortality rate was lower compared to a prior outbreak reported in this facility.