Prevalence, incidence and longevity of antibodies against SARS-CoV-2 among primary healthcare providers in Belgium: a prospective cohort study with 12 months of follow-up

Abstract

ObjectivesTo estimate the prevalence, incidence and longevity of antibodies against SARS-CoV-2 among primary healthcare providers (PHCPs).DesignProspective cohort study with 12 months of follow-up.SettingPrimary care in Belgium.ParticipantsAny general practitioner (GP) working in primary care in Belgium and any other PHCP from the same GP practice who physically manages (examines, tests, treats) patients were eligible. A convenience sample of 3648 eligible PHCPs from 2001 GP practices registered for this study (3044 and 604 to start in December 2020 and January 2021, respectively). 3390 PHCPs (92,9%) participated in their first testing time point (2820 and 565, respectively) and 2557 PHCPs (70,1%) in the last testing time point (December 2021).InterventionsParticipants were asked to perform a rapid serological test targeting IgM and IgG against the receptor binding domain of SARS-CoV-2 and to complete an online questionnaire at each of maximum eight testing time points.Primary and secondary outcome measuresThe prevalence, incidence and longevity of antibodies against SARS-CoV-2 both after natural infection and after vaccination.ResultsAmong all participants, 67% were women and 77% GPs. Median age was 43 years. The seroprevalence in December 2020 (before vaccination availability) was 15.1% (95% CI 13.5% to 16.6%), increased to 84.2% (95% CI 82.9% to 85.5%) in March 2021 (after vaccination availability) and reached 93.9% (95% CI 92.9% to 94.9%) in December 2021 (during booster vaccination availability and fourth (delta variant dominant) COVID-19 wave). Among not (yet) vaccinated participants the first monthly incidence of antibodies against SARS-CoV-2 was estimated to be 2.91% (95% CI 1.80% to 4.01%). The longevity of antibodies is higher in PHCPs with self-reported COVID-19 infection.ConclusionsThis study confirms that occupational health measures provided sufficient protection when managing patients. High uptake of vaccination resulted in high seroprevalence of SARS-CoV-2 antibodies in PHCPs in Belgium. Longevity of antibodies was supported by booster vaccination and virus circulation.Trial registration numberNCT04779424.

SARS-CoV-2 infection prevalence and associated factors among primary healthcare workers in France after the third COVID-19 wave

“…Our results suggest that PHCWs were not at higher risk of SARS-CoV-2 infection than the general adult population (19–64 years old) over the first eighteen months of the pandemic. These findings are consistent with some studies 4 , 6 , 7 but conflicting with others 5 . The discrepancies in results may be explained by the study periods.…”

“…Previous studies showed substantial variability in prevalence and risk factors for SARS-CoV-2 infection among HCWs, attributed to different job roles, exposure to COVID-19 patient, access to PPE, data collection periods, and community prevalence 3 , 4 . Some studies reported a higher risk (between two- and seven-fold) of infection among HCWs from hospital or other healthcare settings than in the general population 5 , while others have not found such differences 4 , 6 , 7 . While some authors reported a dose–response association between COVID-19-patient exposure and the risk of SARS-CoV-2 infection 8 , 9 , others showed that community exposure was associated with infection but workplace factors were not 10 – 12 .…”

Validation of a rapid SARS-CoV-2 antibody test in general practice

“…Of note, in our cohort study we observed an RST-based prevalence of up to 93.9% in December 2021,4 37 which is higher than what could be expected with the sensitivity and specificity of the RST estimated in this validation study. As shown in figure 2, using imperfect sensitivity and specificity estimates overestimates/underestimates true seroprevalence.…”

Post-Acute Sequelae After Severe Acute Respiratory Syndrome Coronavirus 2 Infection by Viral Variant and Vaccination Status: A Multicenter Cross-Sectional Study

“…Important strengths of our study are the clearly defined infection and vaccine status of every individual study participant and the relatively large share of previously unvaccinated participants. This enabled us to adequately disentangle the effects of viral variant and of SARS-CoV-2 vaccination on the occurrence of PASC symptoms, a task which is increasingly becoming unrealizable due to high vaccination and infection rates [ 38 ]. Probably the most important strength is the inclusion of uninfected controls using (repetitive) SARS-CoV-2 serologies.…”