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SSRN; 2022.
Preprint in English | SSRN | ID: ppcovidwho-334503


Evolving SARS-CoV-2 variants and changing levels of pre-existing immunity require re-evaluation of rapid antigen test performance. In hospital employees in Berlin, Germany, from late 2020 to early 2022, we found decreasing rapid antigen test sensitivity over time, from 80% to 67%, despite a 5·6 fold increase in median viral RNA concentrations in symptomatic employees early in their infection course. These changes were observed in parallel with a sharp increase of the percentage of employees who were at least doubly vaccinated or recovered from SARS-CoV-2 infection. Based on statistical analyses of our employee testing data set, an evaluation of antigen test performance on supernatants from SARS-CoV-2 infected cells, and rapid antigen test performance data from other studies, we hypothesize that the observed reduction in clinical rapid test sensitivity, despite higher SARS-CoV-2 RNA loads, is due to increased population immunity resulting from vaccination and prior infection. Funding: Parts of this work were supported by grants from the Berlin University Alliance (Corona Virus Pre-Exploration Project). The study was further supported by the German Ministry of Education and Research through Forschungsnetzwerk der Universitätsmedizin zu COVID-19, (COVIM, FKZ: 01KX2021) to JS, CD, VMC;NIAID-NIH CEIRS contract HHSN272201400008C to TCJ;NaFoUniMedCovid19 (FKZ: 01KX2021) B-FAST to JS;RAPID (01KI1723A) to CD;VARIPath (01KI2021) to VMC, as well as the European Union via Project ReCoVer (grant number GA101003589) to CD. VMC is supported by the Berlin Institute of Health (BIH) Charité Clinician Scientist program.

Immun Inflamm Dis ; 9(4): 1809-1814, 2021 12.
Article in English | MEDLINE | ID: covidwho-1413674


BACKGROUND: A total of 62/66 (93.9%) residents in a senior citizen home in Bremen, Germany, received the first dose of the Biontech/Pfizer vaccine BNT162b2 on December 27th 2020. After routine severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen tests showed positive results on January 5th, all residents and staff were tested by RT-PCR. RESULTS: Nine staff members and 23 residents had a positive result. PCR positive staff members reported mild to severe COVID-19 symptoms, one was hospitalized. None of them had been vaccinated. In contrast, the vaccinated residents reported no or only mild symptoms. Sequencing of the SARS-CoV-2 genomes of infected individuals revealed a monophyletic origin of the outbreak within the PANGO lineage B.1.177.86. CONCLUSIONS: In summary, our data show that partial vaccination prevented severe COVID-19 among the residents during this local SARS-CoV-2 outbreak, suggesting a high effectiveness of even a single vaccine dose, but also emphasize that asymptomatic individuals might still be carriers/spreaders.

COVID-19 , Vaccines , Aged , COVID-19 Vaccines , Disease Outbreaks , Germany , Humans , SARS-CoV-2
Science ; 373(6551)2021 07 09.
Article in English | MEDLINE | ID: covidwho-1243685


Two elementary parameters for quantifying viral infection and shedding are viral load and whether samples yield a replicating virus isolate in cell culture. We examined 25,381 cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Germany, including 6110 from test centers attended by presymptomatic, asymptomatic, and mildly symptomatic (PAMS) subjects, 9519 who were hospitalized, and 1533 B.1.1.7 lineage infections. The viral load of the youngest subjects was lower than that of the older subjects by 0.5 (or fewer) log10 units, and they displayed an estimated ~78% of the peak cell culture replication probability; in part this was due to smaller swab sizes and unlikely to be clinically relevant. Viral loads above 109 copies per swab were found in 8% of subjects, one-third of whom were PAMS, with a mean age of 37.6 years. We estimate 4.3 days from onset of shedding to peak viral load (108.1 RNA copies per swab) and peak cell culture isolation probability (0.75). B.1.1.7 subjects had mean log10 viral load 1.05 higher than that of non-B.1.1.7 subjects, and the estimated cell culture replication probability of B.1.1.7 subjects was higher by a factor of 2.6.

Asymptomatic Infections , COVID-19/transmission , COVID-19/virology , SARS-CoV-2/physiology , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19 Nucleic Acid Testing , Caco-2 Cells , Child , Child, Preschool , Female , Germany , Hospitalization , Humans , Infant , Male , Middle Aged , Probability , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity , Viral Load , Virus Replication , Virus Shedding , Young Adult