Anti-SARS-CoV-2 IgA Identifies Asymptomatic Infection in First Responders.
J Infect Dis
; 225(4): 578-586, 2022 02 15.
Article
in English
| MEDLINE | ID: covidwho-1462363
ABSTRACT
BACKGROUND:
Immunoglobulin A (IgA) is an important component of the early immune response to SARS-CoV-2. Prior serosurveys in high-risk groups employing IgG testing alone have provided discordant estimates. The potential added benefit of IgA in serosurveys has not been established.METHODS:
Longitudinal serosurvey of first responders (police, emergency medical service providers, fire fighters, and other staff) employing 3 serologic tests (anti-spike IgA, anti-spike IgG, and anti-nucleocapsid IgG) correlated with surveys assessing occupational and nonoccupational risk, exposure to COVID-19, and illnesses consistent with COVID-19.RESULTS:
Twelve percent of first responders in Colorado at baseline and 22% at follow-up were assessed as having SARS-CoV-2 infection. Five percent at baseline and 6% at follow-up were seropositive only for IgA. Among those IgA positive only at baseline, the majority (69%) had a positive antibody at follow-up; 45% of those infected at baseline and 33% at follow-up were asymptomatic. At all time points, the estimated cumulative incidence in our study was higher than that in the general population.CONCLUSIONS:
First responders are at high risk of infection with SARS-CoV-2. IgA testing identified a significant portion of cases missed by IgG testing and its use as part of serologic surveys may improve retrospective identification of asymptomatic infection.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Immunoglobulin A
/
Asymptomatic Infections
/
Emergency Responders
/
COVID-19
/
Antibodies, Viral
Type of study:
Cohort study
/
Diagnostic study
/
Experimental Studies
/
Observational study
/
Prognostic study
/
Randomized controlled trials
Limits:
Humans
Language:
English
Journal:
J Infect Dis
Year:
2022
Document Type:
Article
Affiliation country:
Infdis
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