ABSTRACT
Background: The identification of SARS-CoV-2 antigen or RNA in a respiratory specimen collected from a person ≥14 days after completing all recommended doses of authorized COVID-19 vaccine series is a rare condition and defined as „breakthrough infection“. Data on mildly symptomatic or asymptomatic SARS-CoV-2 vaccine breakthrough infection cases especially with respect to viral characteristics and temporal relation to vaccination date is scarce. The purpose of the present investigation was to investigate the prevalence of postvaccination infections in hospital employees and to compare between m-RNA and vector based SARS-CoV-2 vaccines.Methods: At the General Hospital of Vienna 8 553 actively employed staff members participated at an voluntary in-house vaccination program, which took place between January and May 2021 and comprised of application of two doses of either COMIRNATY (BNT162b2; Pfizer/BioNTech, Inc.) or VAXZEVRIA (AstraZeneca, Inc.). Findings: By the end of July 2021 a total of 78 postvaccination infection cases after administration of a minimum of one dose of vaccination had been identified (median age: 40·5 years (IQR: 19-60 years); 53 women) of whom 53 had been vaccinated with VAXZEVRIA and 25 with COMIRNATY. The majority of infections was related to an insufficient or partial vaccination status; the incidence of postvaccination infection ≥14 days after complete vaccination (i.e. breakthrough infection) was 34·8: 10 000 for COMIRNATY and 8·8: 10 000 for VAXZEVRIA. There was no difference in PCR-CT values between the two vaccine brands (24·67 (SD: 7·41) for VAXZEVRIA vaccinated versus 24·0 (SD: 6·53) for COMIRNATY vaccinated persons). Genotyping of positive PCR specimens revealed 42 variant of concerns: B.1.1.7 (n=34); B.1.351 (n=2), B.1.617.2 (n=6). The prevalence of „real brakthrough infections“ (≥14 days after second vaccination) was higher in COMIRNATY vaccinated subjects than in the VAXZEVRIA vaccinated subjects with a ratio of 14:4 (p<0,01). Interpretation: mRNA and vector vaccines against COVID-19 are both highly effective in protecting against a broad genomic spectrum of SARS-CoV-2 infections, at least with respect to severe illness. In the present investigation VAXZEVRIA was more effective than COMIRNATY with respect to prevent breakthrough infections after full immunization, however, it seems important, that all recommended vaccine doses are applicated. Maintaining distinct precautions and ongoing testing, at least for the immediate period after vaccination, to detect asymptomatic infections is highly recommended.Funding: None to declare. Declaration of Interest: We decline no conflicting interest. Ethical Approval: The study was approved by the ethics committee of the Medical University of Vienna [No.1721/2021] and the medical directorate of the hospital.
Subject(s)
Sialic Acid Storage Disease , Encephalomyelitis, Acute Disseminated , Breakthrough Pain , COVID-19ABSTRACT
Background: New commercially available point-of-care (POC) immunodiagnostic tests are appearing, which may yield rapid results for anti-SARS-CoV-2 antibodies. The aim of this study was to evaluate the diagnostic accuracy of rapid antibody detection tests compared to a validated laboratory-based enzyme-linked immunosorbent assay (ELISA) and to investigate infections amongst healthcare workers (HCWs) after unprotected close contact to COVID-19 patients. Methods: Blood serum and whole blood of 130 participants were tested with NADAL® COVID-19 IgG/IgM Rapid Test and mö-screen 2019-NCOV Corona Virus Test against a validated ELISA test. Infection status was evaluated using real-time polymerase-chain-reaction.Results: Acute COVID-19 infection was detected in 2.4% of exposed HCWs. Antibody tests showed an overall frequency of IgG and IgM in 5.3%, with 1.6% asymptomatic infections. The NADAL® test showed a sensitivity (IgM/ IgG) of 100% (100%/ 100%), a specificity (IgM/ IgG) of 98.8% (97.6%/ 100 %), a PPV of 76.9% (57.1%/ 100%), an NPV of 100% (100%/ 100%), and a diagnostic accuracy of 98.8% (97.7%/ 100%). The mö-screen test had a sensitivity (IgM/IgG) of 90.9% (80%/ 100%), a specificity (IgM/IgG) of 98.8% (97.6%/ 100%), a PPV of 76.9% (57.1%/ 100%), an NPV of 99.6% (99.2%/ 100%), and a diagnostic accuracy of 98.5% (96.9%/ 100%). Conclusions: The frequency of COVID-19 infections in HCWs after unprotected close contact is higher than in the general population of a low-prevalence country. Both POC tests were useful for detecting IgG, but did not perform well for IgM, mainly due to false positive results.