Seroprevalence of COVID-19 IgG antibodies among healthcare workers of Pakistan: a cross-sectional study assessing exposure to COVID-19 and identification of high-risk subgroups

Abstract

Objective In this study, we aimed to find the seroprevalence of healthcare workers (HCWs) of Pakistan involved in the treatment and care of patients with COVID-19.Setting This was a cross-sectional study and total of 15 000 HCWs involved in providing services and care to the patients with COVID-19 were randomly selected from all over Pakistan.Participants Informed consent was taken from all participants and were included according to inclusion and exclusion criteria. All testing was done on serum samples for the qualitative detection of SARS-CoV-2 IgG antibodies using Abbott Chemiluminescent microparticle immunoassay. An index of 1.4 was used as a cut-off to mark reactive and non-reactive cases. SPSS V.23.0 was used for data analysis.Outcome Immune status of the study population depicting seroprevalence among HCWs.Results Out of all the candidates, majority of the HCWs were men (61.9%) and were doctors (62.4%). The mean age of participants was 32.8 years (SD 8.7) and majority were asymptomatic (51.8%). In this study, 33% of the HCWs were reactive for SARS-CoV-2 IgG antibody. Around 44% of the reactive cases were asymptomatic. The symptoms more significantly associated with seropositivity were: fever (OR 1.31; 95% CI 1.16 to 1.48), headache (OR 2.43; 95% CI 2.16 to 2.73), cough and shortness of breath (OR 2.10; 95% CI 1.91 to 2.31), loss of sense of smell or taste (OR 3.70; 95% CI 3.29 to 4.17) (p<0.001). Factors which showed significant association with the presence of antibodies were professional category (absolute risk (AR) 0.09; OR 1.46; 95% CI 1.36 to 1.56), availability of protective masks (AR 0.02; OR 0.90; 95% CI 0.84 to 0.96), safety goggles (AR 0.02; OR 0.90; 95% CI 0.84 to 0.97) and living arrangements (AR 0.03; OR 1.12; 95% CI 1.04 to 1.20) (p<0.05).Conclusion Our study showed a high seropositivity of HCWs dealing with patients with COVID-19 in Pakistan revealing significant association with professional category, nature of work place and precautions taken while performing duties.