Abstract
Objectives: In December 2020, Italy began a national immunization campaign using the BNT162b2 coronavirus disease 2019 (COVID-19) mRNA vaccine, prioritizing healthcare workers (HCWs). Immune serum from vaccinated subjects seems (largely) to retain titres of neutralizing antibodies, even against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VOC 202012/01-lineage B.1.1.7. Here, we describe an outbreak of SARS-CoV-2 lineage B.1.1.7 infection in three HCWs in a hospital setting; two of the HCWs were fully vaccinated (i.e. had received two doses).
Methods: Two physicians and one nurse working on the same shift on 20th February 2021 were involved in the outbreak. Real-time PCR, antigen tests, and serological tests for the IgG anti-spike protein of SARS-CoV-2 were performed, along with whole-genome sequencing (WGS).
Results: SARS-CoV-2 infection was confirmed in all three HCWs; all presented with mild symptoms of COVID-19. The two physicians were fully vaccinated with BNT162b2 vaccine, with the second dose administered 1 month before symptom onset. Both had high titres of IgG anti-spike antibodies at the time of diagnosis. WGS confirmed that all virus strains were VOC 202012/01-lineage B.1.1.7, suggesting a common source of exposure. Epidemiological investigation revealed that the suspected source was a SARS-CoV-2-positive patient who required endotracheal intubation due to severe COVID-19. All procedures were carried out using a full suite of personal protective equipment (PPE).
Conclusions: This mini-outbreak highlights some important issues about the efficacy of vaccines against transmission of SARS-CoV-2 variants, the high risk of exposure among HCWs, and the need for optimized implementation of PPE in hospitals. The wide circulation of VOC 202012/01 in Europe and Italy highlights the need to improve surveillance and genetic sequencing.
Keywords: COVID-19; Healthcare workers; Outbreak; SARS-CoV-2 VOC 202012/01-LINEAGE B.1.1.7; Vaccine; Whole-genome sequencing.
【저자키워드】 COVID-19, whole-genome sequencing, Vaccine, Healthcare workers, outbreak, SARS-CoV-2 VOC 202012/01-LINEAGE B.1.1.7, 【초록키워드】 coronavirus disease, whole-genome sequencing, serological test, SARS-CoV-2, IgG, Personal protective equipment, Coronavirus disease 2019, Efficacy, BNT162b2 vaccine, coronavirus, Europe, Healthcare workers, severe COVID-19, Neutralizing antibodies, mRNA vaccine, VoC, SARS-COV-2 infection, hospital, Sequencing, Genetic, Infection, Diagnosis, Italy, severe acute respiratory syndrome Coronavirus, immunization, variants, healthcare worker, hospitals, Antigen, BNT162b2, Protein, PCR, Serological tests, Surveillance, SARS-CoV-2 variants, Real-time PCR, B.1.1.7, HCWs, implementation, Patient, PPE, VOC 202012/01, antigen tests, circulation, respiratory, WGS, mild symptoms, Epidemiological investigation, Anti-spike, Endotracheal intubation, high risk, HCW, Immune Serum, symptom onset, acute respiratory syndrome, Mild symptom, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, titres, subject, second dose, titre, doses, National, physician, transmission of SARS-CoV-2, virus strain, Administered, SARS-CoV-2 lineage, MINI, IgG anti-Spike antibodies, highlight, IMPROVE, performed, carried, involved, required, IgG anti-spike antibody, 【제목키워드】 SARS-CoV-2, VoC, Infection, symptomatic, healthcare, investigation,