Severe acute respiratory syndrome coronavirus 2 breakthrough infections in healthcare workers vaccinees with BNT162b2 (Pfizer-BioNtech) in Bogota, Colombia

The healthcare workers are considered as a high-risk group for infection with SARS-CoV-2, so they were included in the first stage of the National Plan for Vaccination against COVID-19 in Colombia. An ongoing prospective cohort study to evaluate immune response to vaccination included 490 workers from health institutions in Bogota, Colombia, vaccinated between March and June 2021 with BNT162b2 (Pfizer-BioNtech). Multiple samples were collected during a follow-up period of 6 months after immunization. We report cases of asymptomatic and symptomatic SARS-CoV-2 infections detected in this cohort. For each participant demographic data, vaccination dates, results for SARS-CoV-2 RT-PCR, and detection of antibody (IgG) tests during the follow-up period were collected. SARS-CoV-2 infection was detected in 38 (7.7 %) volunteers. Of these, 81.6% had a positive RT-PCR for SARS-CoV-2, and 18.4% were confirmed by detection of IgG anti-SARS-CoV-2 nucleoprotein; 76.3% of infections occurred after 7 days of second dose. A total of 57.9% of the cases were asymptomatic. No hospitalizations or deaths were registered. When infection occurred, 81.6% of infected participants had presence of IgG anti-S antibodies. In 12 samples in which genomic characterization was achieved, 83.4% corresponded to the variant Mu, 8.3% Gamma, and 8.3% Delta. All findings agree with other reports in different studies that show the benefit of COVID-19 vaccines, protecting specially against severe disease but not against infection or re-infection.