tetano
Editor, Senior Moderator
Clin Microbiol Infect
. 2021 Sep 17;S1198-743X(21)00495-X.
doi: 10.1016/j.cmi.2021.09.005. Online ahead of print.
Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through six months: a Danish observational cohort study of 44,000 healthcare workers
Kasper Iversen[SUP] 1 [/SUP], Jonas Henrik Kristensen[SUP] 2 [/SUP], Rasmus Bo Hasselbalch[SUP] 2 [/SUP], Mia Pries-Heje[SUP] 3 [/SUP], Pernille Brok Nielsen[SUP] 2 [/SUP], Andreas Dehlbæk Knudsen[SUP] 4 [/SUP], Kamille Fogh[SUP] 2 [/SUP], Jakob Boesgaard Norsk[SUP] 2 [/SUP], Ove Andersen[SUP] 5 [/SUP], Thea Køhler Fischer[SUP] 6 [/SUP], Claus Antonio Juul Jensen[SUP] 7 [/SUP], Christian Torp-Pedersen[SUP] 6 [/SUP], Jørgen Rungby[SUP] 8 [/SUP], Sisse Bolm Ditlev[SUP] 9 [/SUP], Ida Hageman[SUP] 10 [/SUP], Rasmus Møgelvang[SUP] 3 [/SUP], Mikkel Gybel-Brask[SUP] 11 [/SUP], Ram B Dessau[SUP] 12 [/SUP], Erik Sørensen[SUP] 11 [/SUP], Lene Harritshøj[SUP] 11 [/SUP], Fredrik Folke[SUP] 13 [/SUP], Curt Sten[SUP] 14 [/SUP], Maria Elizabeth Engel Møller[SUP] 15 [/SUP], Thomas Benfield[SUP] 16 [/SUP], Henrik Ullum[SUP] 17 [/SUP], Charlotte Sværke Jørgensen[SUP] 17 [/SUP], Christian Erikstrup[SUP] 18 [/SUP], Sisse R Ostrowski[SUP] 11 [/SUP], Susanne Dam Nielsen[SUP] 19 [/SUP], Henning Bundgaard[SUP] 20 [/SUP]
Affiliations
Abstract
Objectives: Antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are a key factor against COVID-19. We examined longitudinal changes in seroprevalence in healthcare workers (HCW) in Copenhagen and the protective effect of antibodies against SARS-CoV-2.
Methods: In this prospective study, screening for antibodies against SARS-CoV-2 (ELISA) was offered to HCW three times over six months. HCW-characteristics were obtained by questionnaires. ClinicalTrials.gov, NCT04346186.
Results: From April to October 2020 we screened 44,698 HCW of which 2,811 were seropositive at least once. The seroprevalence increased from 4.0% (1,501/37,452) to 7.4% (2,022/27,457) during the period (p<0.001) and was significantly higher than in non-HCW. Frontline HCW had a significantly increased risk of seropositivity compared to non-frontline HCW with risk ratios (RR) at the three rounds of 1.49 (95% CI 1.34-1.65, p<0.001), 1.52 (1.39-1.68, p<0.001) and 1.50 (1.38-1.64, p<0.001). The seroprevalence was 1.42- to 2.25-fold higher (p<0.001) in HCW from dedicated COVID-19 wards compared to other frontline HCW. Seropositive HCW had a RR of 0.35 (0.15-0.85, p=0.012) of reinfection during the following six months and 2,115 (95%) out of 2,248 of those who were seropositive during rounds one or two remained seropositive after four to six months. The 133 of 2,248 (5.0%) participants who seroreverted were slightly older and reported fewer symptoms than other seropositive participants.
Conclusions: HCW remained at increased risk of infection with SARS-CoV-2 during the six months period. Seropositivity against SARS-CoV-2 persisted for at least six months in the vast majority of HCW and was associated with a significantly lower risk of reinfection.
. 2021 Sep 17;S1198-743X(21)00495-X.
doi: 10.1016/j.cmi.2021.09.005. Online ahead of print.
Seroprevalence of SARS-CoV-2 antibodies and reduced risk of reinfection through six months: a Danish observational cohort study of 44,000 healthcare workers
Kasper Iversen[SUP] 1 [/SUP], Jonas Henrik Kristensen[SUP] 2 [/SUP], Rasmus Bo Hasselbalch[SUP] 2 [/SUP], Mia Pries-Heje[SUP] 3 [/SUP], Pernille Brok Nielsen[SUP] 2 [/SUP], Andreas Dehlbæk Knudsen[SUP] 4 [/SUP], Kamille Fogh[SUP] 2 [/SUP], Jakob Boesgaard Norsk[SUP] 2 [/SUP], Ove Andersen[SUP] 5 [/SUP], Thea Køhler Fischer[SUP] 6 [/SUP], Claus Antonio Juul Jensen[SUP] 7 [/SUP], Christian Torp-Pedersen[SUP] 6 [/SUP], Jørgen Rungby[SUP] 8 [/SUP], Sisse Bolm Ditlev[SUP] 9 [/SUP], Ida Hageman[SUP] 10 [/SUP], Rasmus Møgelvang[SUP] 3 [/SUP], Mikkel Gybel-Brask[SUP] 11 [/SUP], Ram B Dessau[SUP] 12 [/SUP], Erik Sørensen[SUP] 11 [/SUP], Lene Harritshøj[SUP] 11 [/SUP], Fredrik Folke[SUP] 13 [/SUP], Curt Sten[SUP] 14 [/SUP], Maria Elizabeth Engel Møller[SUP] 15 [/SUP], Thomas Benfield[SUP] 16 [/SUP], Henrik Ullum[SUP] 17 [/SUP], Charlotte Sværke Jørgensen[SUP] 17 [/SUP], Christian Erikstrup[SUP] 18 [/SUP], Sisse R Ostrowski[SUP] 11 [/SUP], Susanne Dam Nielsen[SUP] 19 [/SUP], Henning Bundgaard[SUP] 20 [/SUP]
Affiliations
- PMID: 34543759
- DOI: 10.1016/j.cmi.2021.09.005
Abstract
Objectives: Antibodies to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are a key factor against COVID-19. We examined longitudinal changes in seroprevalence in healthcare workers (HCW) in Copenhagen and the protective effect of antibodies against SARS-CoV-2.
Methods: In this prospective study, screening for antibodies against SARS-CoV-2 (ELISA) was offered to HCW three times over six months. HCW-characteristics were obtained by questionnaires. ClinicalTrials.gov, NCT04346186.
Results: From April to October 2020 we screened 44,698 HCW of which 2,811 were seropositive at least once. The seroprevalence increased from 4.0% (1,501/37,452) to 7.4% (2,022/27,457) during the period (p<0.001) and was significantly higher than in non-HCW. Frontline HCW had a significantly increased risk of seropositivity compared to non-frontline HCW with risk ratios (RR) at the three rounds of 1.49 (95% CI 1.34-1.65, p<0.001), 1.52 (1.39-1.68, p<0.001) and 1.50 (1.38-1.64, p<0.001). The seroprevalence was 1.42- to 2.25-fold higher (p<0.001) in HCW from dedicated COVID-19 wards compared to other frontline HCW. Seropositive HCW had a RR of 0.35 (0.15-0.85, p=0.012) of reinfection during the following six months and 2,115 (95%) out of 2,248 of those who were seropositive during rounds one or two remained seropositive after four to six months. The 133 of 2,248 (5.0%) participants who seroreverted were slightly older and reported fewer symptoms than other seropositive participants.
Conclusions: HCW remained at increased risk of infection with SARS-CoV-2 during the six months period. Seropositivity against SARS-CoV-2 persisted for at least six months in the vast majority of HCW and was associated with a significantly lower risk of reinfection.