PREVALENCE OF ANTIBODIES AGAINST SARS-CoV-2 IN PROFESSIONALS OF A PUBLIC HEALTH LABORATORY AT SAO PAULO, SP, BRAZIL

BackgroundCovid-19 Serology may document exposure and perhaps protection to the virus and serological test may help understand epidemic dynamics. We tested health workers form a public laboratory to evaluate previous exposure to the virus and estimate the prevalence of antibodies against-SARS-CoV-2 in Adolfo Lutz Institute, State of Sao Paulo, Brazil. MethodsThis study was an open, prospective evaluation among professionals of Adolfo Lutz Institute some administrative personnel from the Secretary of Health that shares common areas with the institute. We used a lateral flow immunoassay (rapid test) to detect IgG and IgM for SARS-CoV-2; positive samples were further evaluated using Roche Electrochemiluminescence assay. SARS-CoV-2 RNA by real time reverse transcriptase polymerase chain reaction (RT-PCR) was also offered to participants. ResultsA total of 406 HPs participated. Thirty five (8.6%) tested positive on rapid test and 32 these rapid test seropositive cases were confirmed by ECLIA. 43 HPs had SARS-CoV-2 RNA detected at a median of 33 days, and the three cases not reactive at Roche ECLIA had a previous positive RNA. Outsourced professionals (34% seropositive), males (15%) workers referring COVID-19 patients at home (22%) and those living farther form the institute tended to have higher prevalence of seropositivity, but in multivariable logistic analysis only outsourced workers and those with COVID patients at home remained independently associated to seropositivity. We observed no relation of seropositivity to COVID samples handling. Presence of at least one symptom was common but some clinical manifestations as anosmia/dysgeusia. Fatigue, cough and fever were associated to seropositivity. ConclusionsWe documented a relatively high (8.6%) of anti-SARS-CoV-2 serological reactivity in this population, higher among outsourced workers and those residing with COVID-19 patients. COVID related work did not increased seropositivity. Some symptoms show strong association to COVID-19 serology and may be used in scoring tools for screening or diagnosis in resort limited settings.