Prevalence of antibodies against sars-cov-2 in professionals of a public health laboratory at são paulo, sp, brazil
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Abstract
Background
Covid-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 São Paulo, Brazil.
Methods
This 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.
Results
A 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.
Conclusions
We 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.
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SciScore for 10.1101/2020.10.19.20213421: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IRB: Ethical Issue: The study was reviewed and approved by the ethics committee CAAE: 31924420.8.0000.0059 and written informed consent was obtained from all study participants.
Consent: Ethical Issue: The study was reviewed and approved by the ethics committee CAAE: 31924420.8.0000.0059 and written informed consent was obtained from all study participants.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources The statistical analysis STATA v13.0 program (StataCorp LP, College Station, TX, USA) was used, with a two tailed p <0.05 considered as … SciScore for 10.1101/2020.10.19.20213421: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Institutional Review Board Statement IRB: Ethical Issue: The study was reviewed and approved by the ethics committee CAAE: 31924420.8.0000.0059 and written informed consent was obtained from all study participants.
Consent: Ethical Issue: The study was reviewed and approved by the ethics committee CAAE: 31924420.8.0000.0059 and written informed consent was obtained from all study participants.Randomization not detected. Blinding not detected. Power Analysis not detected. Sex as a biological variable not detected. Table 2: Resources
Software and Algorithms Sentences Resources The statistical analysis STATA v13.0 program (StataCorp LP, College Station, TX, USA) was used, with a two tailed p <0.05 considered as statistically significant. 2.4. STATAsuggested: (Stata, RRID:SCR_012763)StataCorpsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:We recognize some limitations in our study, as : 1-we used the LFIA method as a preliminary assessment and although confirmed most cases with a second, high throughput ECLIA method, false negative cases would not be identified and we can be under estimating the true prevalence, however, the use of serum instead of finger prick drops may have improved sensibility. 2-Despite our efforts, not all employees joined the study and the prevalence does not reflect the actual SARS-CoV-2 seroprevalence of the institute, but more than half of the workers did contributed to this work. 3-The collection of blood samples was in some cases performed in parallel with the gargle / oropharyngeal smear samples, so we cannot exclude that professionals with a detectable RNA result with a negative LFIA test may have become positive over time. 4-some of the questionnaire were not completed by participants limiting the interpretation of some of the results, but the associations reported were very strong and possibly results were not influenced by missing data.
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
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