Introduction The SARS-CoV-2 illness (COVID-19) has spread around the world, primarily through person-to-person transmission, and is a serious public health concern. Based on the severity of illness symptoms, SARS-CoV-2 infection can be classified as either apparent or occult. To date, real-time reverse transcription polymerase chain reaction (RT-PCR) on respiratory specimens, particularly nasopharyngeal and oropharyngeal swabs, or nasopharyngeal wash or aspirate, has been the gold standard for the identification of COVID-19. A negative RT-PCR does not necessarily rule out SARS-CoV-2 infection. Occult COVID-19 infections could least be identified with RT-PCR. Aims and objectives To assess the prevalence of possible occult COVID-19 infection in healthcare personnel by RT-PCR and serology testing for SARS-CoV-2 virus. Methods A cross-sectional study was conducted on health care workers at a tertiary care hospital in South India during the period from October 2020 to January 2021. None of the study participants were vaccinated against COVID-19 during the study period. Nasopharyngeal swabs collected for RT-PCR were tested using Cobas 480 platform (Roche, Basel, Switzerland). Peripheral blood venous sampling was performed to collect EDTA (ethylenediaminetetraacetic acid) and plain samples. SARS-CoV-2 IgG antibodies against spike proteins were estimated using ECI Vitros platform (Ortho Clinical Diagnostics, Raritan, USA). Results The mean age of study participants was 34.78 years (SD±9.51) with an age range of 19-69 years. The study participants were stratified into age groups of 19-25 years, 26-40 years, 41-60 years, and above 60 years, gender, ABO and Rh blood groups, and occupational and further based on their area of work as Covid and Non-Covid for the purpose of statistical analysis. Total 190 samples from healthcare workers (HCWs) were tested for RT-PCR using nasopharyngeal swabs collected at the time of enrolment into the study, and all the 190 samples tested negative for RT-PCR. Among 190 HCW samples screened for SARS-CoV-2-IgG antibodies, 48 (25.3%) were found reactive for IgG antibodies while 142 (74.7%) were found non-reactive. Conclusion Our study findings suggested that using RT-PCR testing, which may only identify those with a prolonged viral shedding period and minimum viral loads, the proportion of asymptomatic/occult infections could be underestimated.
【저자키워드】 SARS-CoV-2, health care workers, Seroprevalence, abo and rh blood groups, sars-cov-2-igg antibodies, 【초록키워드】 COVID-19, public health, antibodies, cross-sectional, SARS-COV-2 infection, severity, hospital, Infection, Gender, SARS-CoV-2 virus, Transmission, RT-PCR, Symptoms, healthcare worker, Spike protein, Spread, Prevalence, Nasopharyngeal swab, IgG antibody, COVID-19 infection, HCWs, serology testing, nasopharyngeal, SARS-CoV-2 IgG antibody, clinical, age, reverse transcription, Swab, USA, group, prolonged viral shedding, Roche, Switzerland, Care, platform, Blood, respiratory specimens, healthcare personnel, statistical analysis, RT-PCR testing, gold standard, oropharyngeal swabs, study period, viral loads, occult, enrolment, EDTA, Basel, South, SARS-CoV-2 illness, negative RT-PCR, peripheral, venous, reactive, polymerase chain, Result, tested, identify, collected, proportion, conducted, was performed, screened, suggested, groups, Total, stratified, study participant, vaccinated against COVID-19, 【제목키워드】 Screening, worker, occult,