SARS-CoV-2 seroprevalence among healthcare workers

COVID-19 deaths in dental occupations and other healthcare occupations among U.S. decedents in 2020

BACKGROUND

Early studies during the COVID-19 pandemic suggested dental occupations were among the highest risk for exposure to SARs-CoV-2 because of multiple factors increasing exposure, including close proximity to unmasked patients and performance of aerosol-generating procedures. However, to date, few studies have investigated COVID-19 deaths in United States dental occupations, and compared COVID-19 deaths among healthcare occupations.

METHODS

We analyzed 2020 mortality data collected by the National Center for Health Statistics' National Vital Statistics System. Multivariable logistic regression was used to generate odds ratios (ORs) and 95% confidence intervals for COVID-19 as the underlying cause of death in relation to occupation in working-age decedents (≤65 years), after adjusting for age, sex, race/ethnicity, education, and medical conditions associated with severe COVID-19.

RESULTS

Dental occupations did not have significantly higher risk for COVID-19 death when compared to all other occupations combined. Among healthcare occupations with frequent, direct patient- or client interactions, LPNs and LVNs, and speech and language pathologists had significantly elevated adjusted ORs for COVID-19 death when compared to dentists, dental hygienists, or dental assistants. Similarly, nurse practitioners had significantly higher ORs for COVID-19 mortality than dentists or dental hygienists, and approached significance when compared to dental assistants. Conversely, massage therapists and other health diagnosing and treating practitioners had significantly lower adjusted ORs for COVID-19 death compared with dental occupations.

CONCLUSION

Our study highlights potential differences in work-related transmission of SARs-CoV-2 and subsequent COVID-19 deaths in healthcare occupations, and furthers a previously limited understanding of COVID-19 deaths in healthcare occupations in 2020, before COVID-19 vaccine availability. Our results indicate that dental occupations were not among the highest, nor lowest risk, healthcare occupations for COVID-19 deaths in 2020, despite their known risks of direct exposure.

Seroprevalence of SARS-CoV-2 IgG among healthcare workers in Lagos, Nigeria

Healthcare workers (HCWs) are disproportionately infected with SARS-CoV-2 when compared to members of the general public; estimating the seroprevalence of SARS-CoV-2 antibody and SARS-CoV-2 infection rate among HCWs is therefore crucial. This study was carried out in four health facilities in Lagos Nigeria to determine the prevalence of IgG antibodies (seroprevalence) and SARS-CoV-2 active infection rate via a positive rtPCR result, the cross-sectional study was conducted between December 2020 and July 2021. Nasopharyngeal and blood samples were collected from HCWs and screened for SARS-CoV-2 infection using the rtPCR technique and antibody using the Abbott anti-SARS-CoV-2 IgG CMIA assay, respectively. Demographic and occupational exposures data were obtained and analysed using descriptive and inferential statistics, variables significant via inferential statistics were subjected to a multivariate analysis. A total of 413 participants were enrolled, with a mean age in years of 38.4±11.0. The seroprevalence was 30.9% (115/372) while 63/395 (15.9%) were actively infected with the virus. HCWs whose job role had direct contact with patients had a higher percentage of SARS-CoV-2 infection when compared with those not in direct contact, also being a health care worker was significantly associated with getting a positive COVID-19 PCR result. In conclusion the SARS-CoV-2 seroprevalence seen in this study was higher than national serosurvey estimates indicating HCWs are at higher risk of COVID-19 infection when compared to the general public. Vaccination and effective implementation of infection control measures are important to protect HCWs.

SARS-CoV-2 infections in "less visible" hospital staff: The roles and safety of environmental services and allied health professionals

BACKGROUND

During the early SARS-CoV-2 pandemic, all healthcare workers had specific and essential functions. However, environmental services (e.g., cleaning staff) and allied health professionals (e.g., physiotherapists) are often less recognised inpatient care. The aim of our study was to evaluate SARS-CoV-2-infection rates and describe risk factors relevant to workplace transmission and occupational safety amongst healthcare workers in COVID-19 hospitals before the introduction of SARS-CoV-2-specific vaccines.

METHODS

This cross-sectional study (from May 2020 to March 2021, standardised WHO early-investigation protocol) is evaluating workplace or health-related data, COVID-19-patient proximity, personal protective equipment (PPE) use, and adherence to infection prevention and control (IPC) measures, anti-SARS-CoV-2-antibody status, and transmission pathways.

RESULTS

Out of n = 221 HCW (n = 189 cleaning/service staff; n = 32 allied health professionals), n = 17 (7.7 %) were seropositive. While even SARS-CoV-2-naïve HCW reported SARS-CoV-2-related symptoms, airway symptoms, loss of smell or taste, and appetite were the most specific for a SARS-CoV-2-infection. Adherence to IPC (98.6 %) and recommended PPE use (98.2 %) were high and not associated with seropositivity. In 70.6 %, transmission occurred in private settings; in 23.5 %, at the workplace (by interaction with SARS-CoV-2-positive colleagues [17.6 %] or patient contact [5.9 %]), or remained unclear (one case).

CONCLUSIONS

Infection rates were higher in all assessed 'less visible' healthcare-worker groups compared to the general population. Our data indicates that, while IPC measures and PPE may have contributed to the prevention of patient-to-healthcare-worker transmissions, infections were commonly acquired outside of work and transmitted between healthcare workers within the hospital. This finding emphasises the importance of ongoing education on transmission prevention and regular infection screenings at work.

The rates and symptoms of natural and breakthrough infection pre- and post- Covid-19 non-mRNA vaccination at various peaks amongst Iranian healthcare workers

BACKGROUND/AIMS

The aim of this study was to determine the rate of natural and breakthrough infection and related symptoms of Covid-19 amongst Iranian healthcare workers (HCWs) who were vaccinated by different non-mRNA-based vaccines at peak points.

METHODS

In this cross-sectional study, the RT-PCR test was performed for a total of 10,581 HCWs suspicious of Covid-19 infection. For each HCW, the frequency of SARS-CoV-2 infection and the time of transmission based on vaccination administration time and schedule were examined during different waves of the pandemic. Based on these findings, the study patients were divided into three groups: natural, natural/breakthrough, and breakthrough.

RESULTS

In total, 53% of the HCWs were exposed to SARS-CoV-2 infection between 1 and 5 times within two years after the current pandemic, while 20.7% and 32.3% experienced natural and breakthrough SARS-CoV-2 infection, respectively. Only 6% of the breakthrough-infected HCWs had naturally contracted SARS-CoV-2 infection during the initial waves. The highest natural peaks of infection occurred during the interval administration of the first and second dose of the first vaccination series, while the single highest peak of breakthrough infection belonged to the Omicron wave. It occurred simultaneously with the administration of the third vaccination dose. On the other hand, the highest rate of reinfection was observed amongst people who had received the Sinopharm and Bharat vaccines full-doses.

CONCLUSION

This study compared the clinical differences between the two peaks of Omicron and Delta. This study indicates the rates of natural and breakthrough SARS-CoV-2 infections according to vaccination schedules and different waves of the pandemic.

The Relative Contributions of Occupational and Community Risk Factors for COVID-19 among Hospital Workers: The HOP-COVID Cohort Study

The relative contributions of occupational and community sources of COVID-19 among health-care workers (HCWs) are still subject to debate. In a cohort study at a 2814-bed tertiary medical center (five hospitals) in the Paris area of France, we assessed the proportion of hospital-acquired cases among staff and identified risk factors. Between May 2020 and June 2021, HCWs were invited to complete a questionnaire on their COVID-19 risk factors. RT-PCR and serology test results were retrieved from the virology department. Mixed-effects logistic regression was used to account for clustering by hospital. The prevalence of COVID-19 was 15.6% (n = 213/1369 respondents) overall, 29.7% in the geriatric hospitals, and 56.8% of the infections were hospital-acquired. On multivariable analyses adjusted for COVID-19 incidence and contact in the community, a significantly higher risk was identified for staff providing patient care (especially nursing assistants), staff from radiology/functional assessment units and stretcher services, and staff working on wards with COVID-19 clusters among patients or HCWs. The likelihood of infection was greater in geriatric wards than in intensive care units. The presence of significant occupational risk factors after adjustment for community exposure is suggestive of a high in-hospital risk and emphasizes the need for stronger preventive measures-especially in geriatric settings. Clinicaltrials.gov NCT04386759.

Sources of coronavirus disease 2019 (COVID-19) exposure among healthcare personnel (HCP) in a large tertiary-care medical center

Objectives

To describe the burden and sources of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among healthcare personnel (HCP), such as occupational role, work setting, vaccination status, and patient contact between March 2020 through May 2022.

Design

Active prospective surveillance.

Setting

Large tertiary-care teaching institution with inpatient and ambulatory care services.

Results

We identified 4,430 cases among HCPs between March 1, 2020, through May 31, 2022. The median age of this cohort was 37 years (range, 18-89); 2,840 (64.1%) were female; and 2,907 (65.6%) were white. Most of the infected HCP were in the general medicine department, followed by ancillary departments and support staff. Less than 10% of HCP SARS-CoV-2-positive cases worked on a COVID-19 unit. Of the reported SARS-CoV-2 exposures, 2,571 (58.0%) were from an unknown source, 1,185 (26.8%) were from a household source, 458 (10.3%) were from a community source, and 211 (4.8%) were healthcare exposures. A higher proportion of cases with reported healthcare exposures was vaccinated with only 1 or 2 doses, whereas a higher proportion of cases with reported household exposure was vaccinated and boosted, and a higher proportion of community cases with reported and unknown exposures were unvaccinated (P < .0001). HCP exposure to SARS-CoV-2 correlated with community-level transmission regardless of type of reported exposure.

Conclusions

The healthcare setting was not an important source of perceived COVID-19 exposure among our HCPs. Most HCPs were not able to definitively identify the source of their COVID-19, followed by suspected household and community exposures. HCP with community or unknown exposure were more likely to be unvaccinated.

Seroepidemiology of SARS-CoV-2 Virus in Healthcare Workers before Circulation of the Omicron Sublineages BA.4/BA.5 in Vojvodina, Serbia

Healthcare workers (HCWs) are a vulnerable and critical population in the ongoing response to the SARS-CoV-2 pandemic. We aimed to estimate the seroprevalence in HCWs considering all of their previous contacts with the SARS-CoV-2 virus and/or the immunity acquired through their immunization against COVID-19 before the advent of the Omicron variants BA.4/BA.5. Serum samples were collected from 28 March to 10 June 2022. We covered 25% out of all the people who worked in some of the government healthcare centers (primary, secondary, and tertiary level) across the entire Autonomous Province of Vojvodina (Northern Serbia). Two serological tests (Anti-SARS-CoV-2 QuantiVac ELISA and LIAISON® SARS-CoV-2 TrimericS) were used to detect anti-spike IgG antibodies. The overall prevalence of the SARS-CoV-2 antibody among the 6936 HCWs was 92.96% [95% CI 92.33−93.55]. Regarding the type of serological test, there was a statistically significant (p = 0.0079) difference of the seropositivity obtained by the LIAISON® SARS-CoV-2 TrimericS (93.87%, 95% CI 92.97−94.69) and Anti-SARS-CoV-2 QuantiVac ELISA (92.23%, 95% CI 91.34−93.06) tests. Seropositivity to SARS-CoV-2 significantly (p < 0.0001) increased with the number of SARS-CoV-2 infections combined with the number of doses of the SARS-CoV-2 vaccines received. A vast majority of the HCWs in Vojvodina had detectable levels of antibodies to the spike protein of SARS-CoV-2, but despite this high seropositivity, it is unknown whether this herd immunity among HCWs is protective against the new variants of concern. Further research should evaluate the rates of reinfections and the associated severity of COVID-19 caused by the Omicron sublineages and/or new variants of SARS-CoV-2 among HCWs.

Low Seroprevalence of SARS-CoV-2 among Healthcare Workers in Malaysia during the Third COVID-19 Wave: Prospective Study with Literature Survey on Infection Prevention and Control Measures

Healthcare workers (HCWs) are at greater risk for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. This serology surveillance study aimed to investigate the prevalence of SARS-CoV-2 antibodies among the HCWs who were asymptomatic during the third wave of COVID-19 in Malaysia. HCWs from the Universiti Sains Malaysia (USM) Health Campus were prospectively recruited between August 2020 and March 2021 on a voluntary basis. Data on socio-demographics, possible risk factors and travel history were recorded. Serological diagnoses from serum samples were examined for total antibodies against SARS-CoV-2 using an immunoassay kit. A literature survey was performed on the compliance with infection and prevention control (IPC) practices for COVID-19 among HCWs. The majority of the total 617 HCWs participating in this study were nurses (64.3%, n = 397), followed by health attendants (20.9%, n = 129), medical doctors (9.6%, n = 59) and others (6.3%, n = 39). Of those, 28.2% (n = 174) claimed to have exposure to COVID-19 cases, including history of close contact and casual contact with infected patients. Most importantly, all serum samples were found to be non-reactive to SARS-CoV-2, although nearly half (40.0%, n = 246) of the HCWs had been involved directly in the management of acute respiratory illness cases. A proportion of 12.7% (n = 78) of the HCWs reported having underlying health problems, such as diabetes mellitus, hypertension and hyperlipidemia. Despite the presence of medical and sociological risks associated with SARS-CoV-2 infections, the current study found zero prevalence of antibodies against SARS-CoV-2 among the HCWs of USM. Based on the literature survey, the vast majority of Malaysian HCWs demonstrated good IPC practices during the pandemic (average percentage ranged between 92.2% and 99.8%). High compliance with IPC measures may have led to the low seroprevalence of SARS-CoV-2 among the HCWs.

SARS-CoV-2 Seroepidemiological Investigation in Jordan: Seroprevalence, Herd Immunity, and Vaccination Coverage. A Population-Based National Study

Background

Population-based serosurveillance is a cornerstone to furthering our understanding of the COVID-19 pandemic at the community levels. In Jordan, four waves (phases) of seroprevalence epidemiological investigations were conducted using representative population-based national samples. This study aims to estimate the population-based seropositivity, herd immunity, and vaccination coverage at the fourth wave.

Methods

Multistage sampling technique was implemented to recruit a nationally representative sample for the fourth wave of the seroprevalence investigation (June to August 2021). Electronically collected data utilized a questionnaire on background demographics, chronic diseases, and COVID-19 vaccination history. Also, blood samples were collected to detect the presence of total Anti-SARS-CoV-2 IgM and IgG using Wantai/ELISA assays. Prevalence estimates were presented using percentage and 95% Confidence Intervals (C.I.).

Results

There were 8821 participants included in this study, with a mean age of 31.3 years, and 61.7% were females. COVID-19 national seroprevalence and vaccination coverage estimates were 74.1% (95% C.I.: 73.1-74.9%) and 38.4% (95% C.I.: 37.1-39.6%), respectively. Among children, seroprevalence estimates were similar to unvaccinated adults. Among COVID-19 adults, 57.2% were vaccinated. Among vaccinated participants, 91.5% were seropositive, while among unvaccinated, 63.2% were seropositive. By age group, seroprevalence ranged between 53.0% and 86.9%. Seroprevalence estimates were significantly different by gender, vaccination status and dose, and residence.

Conclusion

The reported interplay between seropositivity and vaccination coverage estimate seems insufficient to provide herd immunity levels to combat new variants of SARS-CoV-2. Children and healthcare workers seem to be an epidemiologically influential group in spreading COVID-19. As the globe is still grappling with SARS-CoV-2 infection, national seroepidemiological evidence from Jordan calls for more focus on vaccination coverage, especially among epidemiologically vulnerable groups, to optimize herd immunity.

Seroprevalence of SARS-CoV-2 on health professionals via Bayesian estimation: a Brazilian case study before and after vaccines

The increasing number of COVID-19 infections brought by the current pandemic has encouraged the scientific community to analyze the seroprevalence in populations to support health policies. In this context, accurate estimations of SARS-CoV-2 antibodies based on antibody tests metrics (e.g., specificity and sensitivity) and the study of population characteristics are essential. Here, we propose a Bayesian analysis using IgA and IgG antibody levels through multiple scenarios regarding data availability from different information sources to estimate the seroprevalence of health professionals in a Northeastern Brazilian city: no data available, data only related to the test performance, data from other regions. The study population comprises 432 subjects with more than 620 collections analyzed via IgA/IgG ELISA tests. We conducted the study in pre- and post-vaccination campaigns started in Brazil. We discuss the importance of aggregating available data from various sources to create informative prior knowledge. Considering prior information from the USA and Europe, the pre-vaccine seroprevalence means are 8.04% and 10.09% for IgG and 7.40% and 9.11% for IgA. For the post-vaccination campaign and considering local informative prior, the median is 84.83% for IgG, which confirms a sharp increase in the seroprevalence after vaccination. Additionally, stratification considering differences in sex, age (younger than 30 years, between 30 and 49 years, and older than 49 years), and presence of comorbidities are provided for all scenarios.