Seroprevalence of SARS-CoV-2 Binding and Neutralizing Antibodies in Healthcare Workers during the Epidemic Peak in Referral Hospitals and Quarantine Sites: Saudi Arabia

Abstract

Healthcare workers (HCWs) are at high risk for SARS-CoV-2 infection compared to the general population. Here, we aimed to evaluate and characterize the SARS-CoV-2 seropositivity rate in randomly collected samples among HCWs from the largest referral hospitals and quarantine sites during the peak of the COVID-19 epidemic in the city of Jeddah, the second largest city in Saudi Arabia, using a cross-sectional analytic study design. Out of 693 participants recruited from 29 June to 10 August 2020, 223 (32.2%, 95% CI: 28.8–35.8) were found to be confirmed seropositive for SARS-CoV-2 antibodies, and among those 197 (88.3%) had never been diagnosed with COVID-19. Seropositivity was not significantly associated with participants reporting COVID-19 compatible symptoms as most seropositive HCW participants 140 (62.8%) were asymptomatic. The large proportion of asymptomatic SARS-CoV-2 cases detected in our study demands periodic testing as a general hospital policy.

Community-Based Seroprevalence of SARS-CoV-2 Antibodies following the First Wave of the COVID-19 Pandemic in Jazan Province, Saudi Arabia

“…To obtain the maximum sensitivity, samples that tested positive with the commercial ELISA kit were subjected to confirmatory testing using our in-house indirect ELISA to detect IgG antibodies against SARS-CoV-2 S1 and N proteins in serum samples [ 6 ]. Since most of the binding antibodies are generated against the Spike protein (S), which contains within its subunit 1 (S1) the receptor-binding domain (RBD) that facilitates binding to the host cell receptor and against which the majority of antibodies are generated, we only considered samples that were positive for S1 IgG as confirmed positives, as previously described [ 6 , 21 ]. Using Vircell ELISA kits led to the identification of 157/594 SARS-CoV-2 seropositive cases.…”

“…To date, only a small number of serological studies have been conducted in Saudi Arabia and none in Jazan province (summarized in Table 1 ). Furthermore, most of the studies were conducted early in the COVID-19 pandemic in Saudi Arabia and targeted specific populations such as health care workers and blood donors; thus, there is a need for serological studies to be conducted in Saudi Arabia, particularly community-based studies [ 17 , 18 , 19 , 20 , 21 ].…”

“…Population serological data would also be important for decision making on epidemiological control measures and are an essential factor in eliminating the infection [ 13 , 14 , 15 ]. In Saudi Arabia, which experienced the peak of the first wave of the COVID-19 pandemic between May and July 2020, there has been a very limited number of community-based and blood donor-based serological studies on the national and local levels, with seroprevalence rates ranging from 1.6% to 19% [ 16 , 17 , 18 , 19 , 20 , 21 ]. This variation is expected due to the different points in time when studies were conducted (summarized in Table 1 ).…”

Development of Serological Assays and Seroprevalence Studies of the New Coronavirus 2019 (COVID-19): Reports from Saudi Arabia

“…Interestingly, being in close contact with COVID-19 patients in the hospital or performing intubation did not significantly affect the sero-status of healthcare workers [ 36 ]. Recently, a sero-epidemiological study that targeted healthcare workers during the epidemic peak in the country (from 29 June to 10 August 2020) reported remarkably high seroprevalence rate (32.2%) compared to other studies [ 37 ]. Interestingly, 88.3% of positive cases were never diagnosed with COVID-19, and about 62% did not report COVID-19 symptoms [ 37 ].…”

“…After publishing this paper, several other reports on the sero-status of COVID among healthcare workers started to appear [ 22 , 36 , 37 ]. Unlike the nationwide seroprevalence study discussed above, most of these studies were performed on healthcare workers from single hospitals with a relatively limited number of participants [ 22 , 36 ].…”