Longitudinal assessment of SARS-CoV-2 IgG seroconversionamong front-line healthcare workers during the first wave of the Covid 19 pandemic at a tertiary-care hospital in Chile
Date
2021
Type:
Article
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Abstract
Background: Healthcare workers (HCWs) are at high risk of exposure to SARS-CoV-2. Cross-sectional studies have
provided variable rates of seroprevalence in HCWs. Longitudinal assessments of the serological response to Covid 19 among HCWs are crucial to understanding the risk of infection and changes in antibody titers over time. We
aimed to investigate seroprevalence and risk factors associated with seroconversion in a prospective cohort of
HCWs during the peak of the first wave of the Covid-19 pandemic.
Methods: We conducted a longitudinal study among 446 front-line HCWsin a tertiary-care hospital in Chile from
April to July 2020. IgG was determined monthly using two different ELISAs in serum samples of HCWs, during the
three-month period. In each visit, demographic data, symptoms, risk factors, and exposure risks were also assessed.
Results: The overall seroprevalence at the end of the study period was 24% (95% CI20.2–28.3), with 43% of
seropositive HCWs reporting no prior symptoms. Seroconversion rates significantly differed over the study period,
from 2.1% to as high as 8.8% at the peak of the epidemic. There were no statistically significant differences
observed between HCWs in direct clinical care of patients with Covid-19 and those working in low risk areas.
Antibody titers appeared to wane over time.
Conclusions: HCWs were severely affected with a high rate of seroconversion that appeared to mirror the local
epidemiological situation. A significant amount of participants underwent an asymptomatic infection, highlighting
the need for improved surveillance policies. Antibody titers appear to wane over time; further studies to understand
this finding’s impact on the risk of reinfection are warranted
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Citation
Iruretagoyena M, Vial MR, Spencer-Sandino M, Gaete P, Peters A, Delgado I, Perez I, Calderon C, Porte L, Legarraga P, Anderson A, Aguilera X, Vial P, Weitzel T, Munita JM. Longitudinal assessment of SARS-CoV-2 IgG seroconversionamong front-line healthcare workers during the first wave of the Covid-19 pandemic at a tertiary-care hospital in Chile. BMC Infect Dis. 2021 May 26;21(1):478. doi: 10.1186/s12879-021-06208-2
Keywords
Covid-19, SARS-CoV-2, Seroprevalence, Seroconversion, Healthcare workers