Pre-vaccination RT-PCR negative contacts in workplace settings show high, SARS COV-2 neutralizing antibody levels.
BMC Public Health
; 22(1): 1961, 2022 10 25.
Article
in English
| MEDLINE | ID: covidwho-2089185
ABSTRACT
BACKGROUND:
Asymptomatic SARS-CoV-2 infection occurring in RT-PCR negative individuals represent a poorly characterized cohort with important infection control connotations. While household and community-based studies have evaluated seroprevalence of antibody and transmission dynamics in this group, workplace-based data is currently unavailable.METHODS:
A cohort study was carried out in July 2021, during and immediately following the peak of the 3rd wave of COVID-19 in Sri Lanka, prior to mass vaccination. A total of 92 unvaccinated individuals between the ages of 17-65 years were purposively sampled from an office and two factory settings. The selected cohort that had been exposed to RT-PCR positive cases in the workplace was tested RT-PCR negative. Serological samples collected six weeks post exposure were tested for anti-SARS-CoV-2 neutralizing antibody.RESULTS:
The seroprevalence for SARS-CoV-2 specific neutralizing antibodies in the overall cohort was 63.04% (58/92). Seroprevalences in the office setting, factory setting 1 and factory setting 2 were 69.2% (9/13), 55.7% (34/61) and 83.33% (15/18), respectively. Primary risk factor associated with seropositivity was face to face contact with no mask for > 15 min (p < 0.024, Odds Ratio (OR); 5.58, 95%CI;1.292- 25.65). Individuals with workspace exposure had significantly higher levels of neutralizing antibodies than those who did not (percentage neutralization in assay 63.3% (SD21)vs 45.7% (SD20), p = 0.0042), as did individuals who engaged socially without protective measures (62.4 (SD21.6)% vs 49.7 (SD21)%, p = 0.026).CONCLUSION:
There was a high seroprevalence for SARS-CoV-2 specific neutralizing antibodies among RT-PCR negative contacts in workplace settings in Sri Lanka. Higher levels of transmission of SARS-CoV-2 infection than estimated based on RT-PCR positive contact data indicate need for targeted infection control measures in these settings during future outbreaks.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
COVID-19
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
Topics:
Vaccines
Limits:
Adolescent
/
Adult
/
Aged
/
Humans
/
Middle aged
/
Young adult
Language:
English
Journal:
BMC Public Health
Journal subject:
Public Health
Year:
2022
Document Type:
Article
Affiliation country:
S12889-022-14381-5
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