tetano
Editor, Senior Moderator
Clin Infect Dis
. 2025 Jul 30:ciaf339.
doi: 10.1093/cid/ciaf339. Online ahead of print. Incidence of and Risk Factors for SARS-CoV-2 Infection Among Vaccinated Healthcare Workers During Emergence of SARS-CoV-2 Gamma Variant in the Amazon Region, Brazil, 2021
Gemma Parra[SUP] 1 [/SUP], Fernanda C Lessa[SUP] 1 2 [/SUP], Evelyn Campelo[SUP] 3 [/SUP], Tatyana C Amorim Ramos[SUP] 3 [/SUP], Antonio R Vieira[SUP] 2 [/SUP], Pritesh Lalwani[SUP] 4 5 [/SUP], Lucia Y I Nichiata[SUP] 6 [/SUP], Luciana Silva-Flannery[SUP] 2 [/SUP], Charlene Siza[SUP] 1 2 [/SUP], Kassia Janara Veras Lima[SUP] 7 [/SUP], Aida Cristina Tapajos[SUP] 8 [/SUP], Ariana Vieira[SUP] 8 [/SUP], Mateusz Plucinski[SUP] 2 [/SUP], Barbara J Marston[SUP] 2 [/SUP], Juliette Morgan[SUP] 9 [/SUP], Roberto J F Esteves[SUP] 9 [/SUP], Cristiano Fernandes da Costa[SUP] 10 [/SUP], Felipe G Naveca[SUP] 4 [/SUP], Guilherme Araujo[SUP] 11 [/SUP], Maria Clara Padoveze[SUP] 6 [/SUP]; Brazil Healthcare Personnel COVID-19 Team
Collaborators, Affiliations
Background: The emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants poses a significant threat to public health and healthcare workers (HCWs). The SARS-CoV-2 Gamma variant emerged in Manaus, Brazil, in December 2020, leading to a large wave of infections and deaths.
Methods: We conducted a prospective cohort study among HCWs at 2 hospitals in Manaus from 31 March to 31 May 2021. HCWs were followed up for 3 weeks with nasal swabs collected at baseline and weekly (total: 4 visits), regardless of symptoms, for SARS-CoV-2 testing. Blood samples were collected for SARS-CoV-2 serology at baseline. Staff collected data on symptoms, healthcare, and community exposures, and vaccination status at each visit. We evaluated coronavirus disease 2019 (COVID-19) attack rate, risk factors for disease, and differences in rates by vaccination status.
Results: We included 771 HCWs (388 and 383 per hospital). The median age was 40 years (IQR: 31-48), 600 (77.8%) were female, 449 (58.2%) were nurses, and 568 (73.6%) were fully vaccinated at enrollment. We identified 16 SARS-CoV-2 incident infections for an overall attack rate of 5.2 per 1000 HCW-weeks. Of the 16 infected HCWs, 12 were fully vaccinated (attack rate: 5.2/1000 HCW-weeks vs 5.9/1000 HCW-weeks among unvaccinated). All 12 vaccinated HCWs tested negative after 1-week follow-up, while 2 of the 3 infected unvaccinated individuals remained positive at follow-up (P < .05).
Conclusions: The COVID-19 attack rate among this cohort of HCWs with high vaccine coverage was low. Among vaccinated HCWs who tested positive, none tested positive after 1 week, indicating more rapid viral clearance vs unvaccinated HCWs. HCW vaccination is an important measure for HCW safety and more resilient healthcare systems.
Keywords: COVID-19; SARS-CoV-2; healthcare workers; vaccination; variants of concern.
. 2025 Jul 30:ciaf339.
doi: 10.1093/cid/ciaf339. Online ahead of print. Incidence of and Risk Factors for SARS-CoV-2 Infection Among Vaccinated Healthcare Workers During Emergence of SARS-CoV-2 Gamma Variant in the Amazon Region, Brazil, 2021
Gemma Parra[SUP] 1 [/SUP], Fernanda C Lessa[SUP] 1 2 [/SUP], Evelyn Campelo[SUP] 3 [/SUP], Tatyana C Amorim Ramos[SUP] 3 [/SUP], Antonio R Vieira[SUP] 2 [/SUP], Pritesh Lalwani[SUP] 4 5 [/SUP], Lucia Y I Nichiata[SUP] 6 [/SUP], Luciana Silva-Flannery[SUP] 2 [/SUP], Charlene Siza[SUP] 1 2 [/SUP], Kassia Janara Veras Lima[SUP] 7 [/SUP], Aida Cristina Tapajos[SUP] 8 [/SUP], Ariana Vieira[SUP] 8 [/SUP], Mateusz Plucinski[SUP] 2 [/SUP], Barbara J Marston[SUP] 2 [/SUP], Juliette Morgan[SUP] 9 [/SUP], Roberto J F Esteves[SUP] 9 [/SUP], Cristiano Fernandes da Costa[SUP] 10 [/SUP], Felipe G Naveca[SUP] 4 [/SUP], Guilherme Araujo[SUP] 11 [/SUP], Maria Clara Padoveze[SUP] 6 [/SUP]; Brazil Healthcare Personnel COVID-19 Team
Collaborators, Affiliations
- PMID: 40736251
- DOI: 10.1093/cid/ciaf339
Background: The emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants poses a significant threat to public health and healthcare workers (HCWs). The SARS-CoV-2 Gamma variant emerged in Manaus, Brazil, in December 2020, leading to a large wave of infections and deaths.
Methods: We conducted a prospective cohort study among HCWs at 2 hospitals in Manaus from 31 March to 31 May 2021. HCWs were followed up for 3 weeks with nasal swabs collected at baseline and weekly (total: 4 visits), regardless of symptoms, for SARS-CoV-2 testing. Blood samples were collected for SARS-CoV-2 serology at baseline. Staff collected data on symptoms, healthcare, and community exposures, and vaccination status at each visit. We evaluated coronavirus disease 2019 (COVID-19) attack rate, risk factors for disease, and differences in rates by vaccination status.
Results: We included 771 HCWs (388 and 383 per hospital). The median age was 40 years (IQR: 31-48), 600 (77.8%) were female, 449 (58.2%) were nurses, and 568 (73.6%) were fully vaccinated at enrollment. We identified 16 SARS-CoV-2 incident infections for an overall attack rate of 5.2 per 1000 HCW-weeks. Of the 16 infected HCWs, 12 were fully vaccinated (attack rate: 5.2/1000 HCW-weeks vs 5.9/1000 HCW-weeks among unvaccinated). All 12 vaccinated HCWs tested negative after 1-week follow-up, while 2 of the 3 infected unvaccinated individuals remained positive at follow-up (P < .05).
Conclusions: The COVID-19 attack rate among this cohort of HCWs with high vaccine coverage was low. Among vaccinated HCWs who tested positive, none tested positive after 1 week, indicating more rapid viral clearance vs unvaccinated HCWs. HCW vaccination is an important measure for HCW safety and more resilient healthcare systems.
Keywords: COVID-19; SARS-CoV-2; healthcare workers; vaccination; variants of concern.