Severe acute respiratory syndrome coronavirus 2 vaccine breakthrough infections: A single metro-based testing network experience.

Objectives: Understanding the incidence and characteristics that influence severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine breakthrough infections (VBIs) is imperative for developing public health policies to mitigate the coronavirus disease of 2019 (COVID-19) pandemic. We examined these factors and post-vaccination mitigation practices in individuals partially and fully vaccinated against SARS-CoV-2. Materials and methods: Adults >18 years old were voluntarily enrolled from a single metro-based SARS-CoV-2 testing network from January to July 2021. Participants were categorized as asymptomatic or symptomatic, and as unvaccinated, partially vaccinated, or fully vaccinated. All participants had confirmed SARS-CoV-2 infection based on standard of care (SOC) testing with nasopharyngeal swabs. Variant analysis by rRT-PCR was performed in a subset of time-matched vaccinated and unvaccinated individuals. A subgroup of partially and fully vaccinated individuals with a positive SARS-CoV-2 rRT-PCR was contacted to assess disease severity and post-vaccination mitigation practices. Results: Participants ( Conclusion: The incidence of SARS-CoV-2 infection at this center was 21.3% in the partially vaccinated group and 9.4% in the fully vaccinated group. Chronic liver disease and immunosuppression were more prevalent in the vaccinated SARS-CoV-2 positive group, suggesting that these may be risk factors for VBIs. Partially and fully vaccinated individuals had a higher incidence of asymptomatic SARS-CoV-2 and higher C