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We evaluated the Panbio COVID-19 AG Rapid Test Device (RAD) for the diagnosis of COVID-19 in symptomatic patients attended in primary healthcare centers (n=412). Overall specificity and sensitivity of RAD was 100% and 79.6%, respectively, taking RT-PCR as the reference. SARS-CoV-2 could not be cultured from specimens yielding RT-PCR+/RAD- results.

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Objectives: The immunogenicity of the Comirnaty® vaccine against coronavirus disease 2019 (COVID-19) has not been adequately studied in elderly people with comorbidities. We assessed antibody and T-cell responses targeted to the S protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) following full vaccination in nursing-home residents. Methods: Sixty nursing-home residents (44 female, age 53e100 years), of whom ten had previously been diagnosed with COVID-19, and 18 healthy controls (15 female, age 27e54 years) were recruited. Pre-and post-vaccination blood specimens were available for quantification of total antibodies binding the SARS-CoV-2 S protein and for enumeration of SARS-CoV-2 S-reactive IFN-g CD4 þ and CD8 þ T cells by flow cytometry. Results: The seroconversion rate in (presumably) SARS-CoV-2-naïve nursing-home residents (41/43, 95.3%) was similar to that in controls (17/18, 94.4%). A booster effect was documented in post-vaccination samples of nursing-home residents with prior COVID-19. Plasma antibody levels were higher (p < 0.01) in recovered nursing-home residents (all 2500 IU/mL) than in individuals across the other two groups (median 1120 IU/mL in naïve nursing-home residents and 2211 IU/ml in controls). A large percentage of nursing-home residents had SARS-CoV-2 S-reactive IFN-g CD8 þ (naïve 31/49, 63.2%; recovered 8/10, 80%) or CD4 þ T cells (naïve 35/49, 71.4%; recovered 7/10, 70%) at baseline, in contrast to healthy controls (3/17, 17.6% and 5/17, 29%, respectively). SARS-CoV-2 IFN-g CD8 þ and CD4 þ T-cell responses were documented in 88% (15/17) and all control subjects after vaccination, respectively, but only in 65.5% (38/ 58) and 22.4% (13/58) of nursing-home residents. Overall, the median frequency of SARS-CoV-2 IFN-g CD8 þ and CD4 þ T cells in nursing-home residents decreased in post-vaccination specimens, whereas it increased in controls. Conclusion:The Comirnaty COVID-19 vaccine elicits robust SARS-CoV-2 S antibody responses in nursinghome residents. Nevertheless, the rate and frequency of detectable SARS-CoV-2 IFN-g T-cell responses after vaccination was lower in nursing-home residents than in controls.