Seroprevalence and longevity of SARS-CoV-2 nucleocapsid antigen-IgG among health care workers in a large COVID-19 public hospital in Saudi Arabia: A prospective cohort study

PLOS ONE RESEARCH ARTICLE Seroprevalence and longevity of SARS-CoV-2 nucleocapsid antigen-IgG among health care workers in a large COVID-19 public hospital in Saudi Arabia: A prospective cohort study Faisal Alasmari ID1,2*, Mahmoud Mukahal1, Alaa Ashraf Alqurashi3, Molla Huq4, Fatima Alabdrabalnabi1, Abdullah AlJurayyan5, Shymaa Moshobab Alkahtani6, Fatimah Salem Assari6, Rahaf Bashaweeh6, Rana Salam7, Solaf Aldera1, Ohud Mohammed Alkinani8, Talal Almutairi9, Kholoud AlEnizi10, Imad Tleyjeh2 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Infection Control and Environmental Health Administration, King Fahad Medical City, Riyadh, Saudi Arabia, 2 Infectious Diseases Section, King Fahad Medical City, Riyadh, Saudi Arabia; College of Medicine, Al Faisal University, Riyadh, Saudi Arabia, 3 Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia, 4 Immunology and Serology Laboratory, King Fahad Medical City, Riyadh, Saudi Arabia, 5 College of Medicine, Al Faisal University, Riyadh, Saudi Arabia, 6 Public Health College, Saudi Electronic University, Riyadh, Saudi Arabia, 7 Infectious Diseases Section, King Fahad Medical City, Riyadh, Saudi Arabia, 8 Pathology and Clinical Laboratory Administration, King Fahad Medical City, Riyadh, Saudi Arabia, 9 Radiology Service Administration, King Fahad Medical City, Riyadh, Saudi Arabia, 10 Research Center, King Fahad Medical City, Riyadh, Saudi Arabia * OPEN ACCESS Citation: Alasmari F, Mukahal M, Alqurashi AA, Huq M, Alabdrabalnabi F, AlJurayyan A, et al. (2022) Seroprevalence and longevity of SARSCoV-2 nucleocapsid antigen-IgG among health care workers in a large COVID-19 public hospital in Saudi Arabia: A prospective cohort study. PLoS ONE 17(8): e0272818. https://doi.org/10.1371/ journal.pone.0272818 Editor: Asep K. Supriatna, Padjadjaran University: Universitas Padjadjaran, INDONESIA Received: December 20, 2021 Accepted: July 26, 2022 Published: August 12, 2022 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0272818 Copyright: © 2022 Alasmari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Seroprevalence of SARS-CoV-2 IgG among health care workers (HCWs) is crucial to inform infection control programs. Conflicting reports have emerged on the longevity of SARSCoV-2 IgG. Our objective is to describe the prevalence of SARS-CoV-2 IgG in HCWs and perform 8 months longitudinal follow-up (FU) to assess the duration of detectable IgG. In addition, we aim to explore the risk factors associated with positive SARS-CoV-2 IgG. The study was conducted at a large COVID-19 public hospital in Riyadh, Saudi Arabia. All HCWs were recruited by social media platform. The SARS-CoV-2 IgG assay against SARSCoV-2 nucleocapsid antigen was used. Multivariable logistic regression was used to examine association between IgG seropositive status and clinical and epidemiological factors. A total of 2528 (33% of the 7737 eligible HCWs) participated in the survey and 2523 underwent baseline serological testing in June 2020. The largest occupation groups sampled were nurses [n = 1351(18%)], physicians [n = 456 (6%)], administrators [n = 277 (3.6%)], allied HCWs [n = 205(3%)], pharmacists [n = 95(1.2%)], respiratory therapists [n = 40 (0.5%)], infection control staff [n = 21(0.27%], and others [n = 83 (1%)]. The total cohort median age was 36 (31–43) years and 66.3% were females. 273 were IgG seropositive at baseline with a seroprevalence of 10.8% 95% CI (9.6%-12.1%). 165/185 and 44/112 were persistently IgG positive, at 2–3 months and 6 months FU respectively. The median (25th– 75th percentile) IgG level at the 3 different time points was 5.86 (3.57–7.04), 3.91 (2.46– 5.38), 2.52 (1.80–3.99) respectively. Respiratory therapists OR 2.38, (P = 0.035), and those with hypertension OR = 1.86, (P = 0.009) were more likely to be seropositive. A high PLOS ONE | https://doi.org/10.1371/journal.pone.0272818 August 12, 2022 1 / 15 PLOS ONE Data Availability Statement: The data underlying the results presented in the study are available from (DOI ). Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Seroprevalence and longevity of SARS-CoV-2 nucleocapsid antigen-IgG among health care workers proportion of seropositive staff had prior symptoms 214/273(78%), prior anosmia was associated with the presence of antibodies, with an odds ratio of 9.25 (P<0.001), as well as fever and cough. Being a non-smoker, non-Saudi, and previously diagnosed with COVID-19 infection by PCR were statistically significantly different by seroprevalence status. We found that the seroprevalence of IgG against SARS-CoV-2 nucleocapsid antigen was 10.8% in HCWs at the peak of the pandemic in Saudi Arabia. We also observed a decreasing temporal trend of IgG seropositivity over 8 months follow up period. Introduction Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. The first case of SARS-CoV-2 infection in Saudi Arabia was reported in Eastern province January 20,2020, with 545829 infections and 8610 deaths as of 11 September 2021 [1]. Health care workers (HCWs) are at an increased risk of becoming infected with SARSCoV-2. Understanding the prevalence of SARS-CoV-2 carriage amongst HCWs is crucial to help monitor transmission dynamics and inform the development of screening programs. Access to COVID-19 molecular testing during early time of pandemic was mainly confined to symptomatic individuals, and therefore the rates of infection in asymptomatic or minimally symptomatic HCWs have been difficult to determine. Serological testing can detect prior SARS-CoV-2 infection for which nasopharyngeal sampling resulted in false negatives or for which reverse transcription-PCR testing was not performed. It requires high sensitivity and specificity, especially when seroprevalence is low, in order to have an acceptable positive predictive value [2]. Several seroprevalence studies of HCWs from different countries in the first phase of the pandemic revealed a wide range of seropositivity [3–6]. The reasons for such variation may reflect the underlying community transmission rate in addition to an increased risk in certain hospital. Conflicting reports have been published on the longevity of SARS-CoV-2 antibodies. For instance, an Iceland study showed IgG antibody levels to Nucleocapsid (NC) and the S1 component of spike were relatively stable in 1215 indivi (...truncated)