Dataset Information

Alpha variant coronavirus outbreak in a nursing home despite high vaccination coverage: molecular, epidemiological and immunological studies.

ABSTRACT:

Background

Vaccination may control the COVID-19 pandemic, including in nursing homes where many high-risk people live. We conducted extensive outbreak investigations.

Methods

We studied an outbreak at a nursing home in Switzerland where vaccination uptake of mRNA vaccines against SARS-CoV-2 was 82% among residents as of Jan 21/2021. After a vaccinated symptomatic HCW was diagnosed with COVID-19 on Feb 22, we did an outbreak investigations in house A (47 residents, 37 HCWs) using SARS-CoV-2-specific PCR in nasopharyngeal swabs. We performed whole-genome sequencing of SARS-CoV-2 and serological analyses.

Results

We identified 17 individuals with positive PCR tests; ten residents (five vaccinated) and seven HCWs (three vaccinated). Median age among residents was 86 years (interquartile range [IQR] 70-90) and 49 years (IQR 29-59) among HCWs. Among the five vaccinated residents, 60% had mild disease and had 40% no symptoms, whereas all five unvaccinated residents had mild to severe disease and two died. The vaccine effectiveness for the prevention of infection among the residents was 73.0% (95% Cl 24.7-90.1). The 12 available genomes were all alpha variants. Neutralizing titers were significantly higher in vaccinated individuals upon re-exposure (>1 week after diagnosis) than in vaccinated, unexposed HCWs (p=0.012). Transmission networks indicated four likely or possible transmissions from vaccinated to other individuals, and 12 transmission events from unvaccinated individuals.

Conclusions

COVID-19 outbreaks can occur in nursing homes, including transmission from vaccinated persons to others. Outbreaks might occur silently, underlining the need for continued testing and basic infection control measures in these high-risk settings.

SUBMITTER: Zurcher K

PROVIDER: S-EPMC9129182 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature

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Publications

Alpha Variant Coronavirus Outbreak in a Nursing Home Despite High Vaccination Coverage: Molecular, Epidemiological, and Immunological Studies.

Zürcher Kathrin K Abela Irene A IA Stange Madlen M Dupont Carole C Mugglin Catrina C Egli Adrian A Trkola Alexandra A Egger Matthias M Fenner Lukas L

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20230801 4

<h4>Background</h4>Vaccination may control the coronavirus disease 2019 (COVID-19) pandemic, including in nursing homes where many high-risk people live. We conducted extensive outbreak investigations.<h4>Methods</h4>We studied an outbreak at a nursing home in Switzerland, where the uptake of messenger RNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was 82% among residents as of 21 January 2021. After diagnosis of COVID-19 in a vaccinated symptomatic healthcare ...[more]

PMID: 35522980

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Project description:BackgroundAfter the first of three COVID-19 vaccination clinics in U.S. nursing homes (NHs), the median vaccination coverage of staff was 37.5%, indicating the need to identify strategies to increase staff coverage. We aimed at comparing the facility-level activities, policies, incentives, and communication methods associated with higher staff COVID-19 vaccination coverage.MethodsDesign. Case-control analysis.SettingNationally stratified random sample of 1338 U.S. NHs participating in the Pharmacy Partnership for Long-Term Care Program.ParticipantsNursing home leadership.MeasurementDuring February 4-March 2, 2021, we surveyed NHs with low (<35%), medium (40%-60%), and high (>75%) staff vaccination coverage, to collect information on facility strategies used to encourage staff vaccination. Cases were respondents with medium and high vaccination coverage, whereas controls were respondents with low coverage. We used logistic regression modeling, adjusted for county and NH characteristics, to identify strategies associated with facility-level vaccination coverage.ResultsWe obtained responses from 413 of 1338 NHs (30.9%). Compared with facilities with lower staff vaccination coverage, facilities with medium or high coverage were more likely to have designated frontline staff champions (medium: adjusted odds ratio [aOR] 3.6, 95% CI 1.3-10.3; high: aOR 2.9, 95% CI 1.1-7.7) and set vaccination goals (medium: aOR 2.4, 95% 1.0-5.5; high: aOR 3.7, 95% CI 1.6-8.3). NHs with high vaccination coverage were more likely to have given vaccinated staff rewards such as T-shirts compared with NHs with low coverage (aOR 3.8, 95% CI 1.3-11.0). Use of multiple strategies was associated with greater likelihood of facilities having medium or high vaccination coverage: For example, facilities that used ≥9 strategies were three times more likely to have high staff vaccination coverage than facilities using <6 strategies (aOR 3.3, 95% CI 1.2-8.9).ConclusionsUse of designated champions, setting targets, and use of non-monetary awards were associated with high NH staff COVID-19 vaccination coverage.