Background BNT162b2 mRNA and ChAdOx1 nCOV-19 adenoviral vector vaccines have been rapidly rolled out in the UK from December, 2020. We aimed to determine the factors associated with vaccine coverage for both vaccines and documented the vaccine effectiveness of the BNT162b2 mRNA vaccine in a cohort of health-care workers undergoing regular asymptomatic testing. MethodsThe SIREN study is a prospective cohort study among staff (aged ≥18 years) working in publicly-funded hospitals in the UK. Participants were assigned into either the positive cohort (antibody positive or history of infection [indicated by previous positivity of antibody or PCR tests]) or the negative cohort (antibody negative with no previous positive test) at the beginning of the follow-up period. Baseline risk factors were collected at enrolment, symptom status was collected every 2 weeks, and vaccination status was collected through linkage to the National Immunisations Management System and questionnaires. Participants had fortnightly asymptomatic SARS-CoV-2 PCR testing and monthly antibody testing, and all tests (including symptomatic testing) outside SIREN were captured. Data cutoff for this analysis was Feb 5, 2021. The follow-up period was Dec 7, 2020, to Feb 5, 2021. The primary outcomes were vaccinated participants (binary ever vacinated variable; indicated by at least one vaccine dose recorded by at least one of the two vaccination data sources) for the vaccine coverage analysis and SARS-CoV-2 infection confirmed by a PCR test for the vaccine effectiveness analysis. We did a mixed-effect logistic regression analysis to identify factors associated with vaccine coverage. We used a piecewise exponential hazard mixed-effects model (shared frailty-type model) using a Poisson distribution to calculate hazard ratios to compare time-to-infection in unvaccinated and vaccinated participants and estimate the impact of the BNT162b2 vaccine on all PCR-positive infections (asymptomatic and symptomatic). This study is registered with ISRCTN, number ISRCTN11041050, and is ongoing.Findings 23 324 participants from 104 sites (all in England) met the inclusion criteria for this analysis and were enrolled. Included participants had a median age of 46•1 years (IQR 36•0-54•1) and 19 692 (84%) were female; 8203 (35%) were assigned to the positive cohort at the start of the analysis period, and 15 121 (65%) assigned to the negative cohort. Total follow-up time was 2 calendar months and 1 106 905 person-days (396 318 vaccinated and 710 587 unvaccinated). Vaccine coverage was 89% on Feb 5, 2021, 94% of whom had BNT162b2 vaccine. Significantly lower coverage was associated with previous infection, gender, age, ethnicity, job role, and Index of Multiple Deprivation score. During follow-up, there were 977 new infections in the unvaccinated cohort, an incidence density of 14 infections per 10 000 person-days; the vaccinated cohort had 71 new infections 21 days or more after their first dose (incidence density of eight infections per 10 000 person-days) and nine infecti...

Background In centre haemodialysis (ICHD) patients have been identified as high risk of contracting Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection due to frequent healthcare contact and poor innate and adaptive immunity. Our ICHD patients were offered immunisation from January 2021. We aimed to assess outcomes following SARS-CoV-2 infection and report on the effect of vaccination in our ICHD patients. Methods Demographics, SARS-CoV-2 status, hospitalisation, mortality and vaccination status were analysed. From 11th March 2020 to 31st March 2021, 662 ICHD patients were included in the study and these patients were then followed up until 31st August 2021. Results SARS-CoV-2 infection occurred in 28.4% with 51.1% of them requiring hospitalisation in contrast to community infection rates of 13.9% and hospitalisation of 9.0%. 28-day mortality was 19.2% in comparison to 1.9% of the community. Mortality increased to 34.0% over the study period. Mortality over the study period was 1.8 times in infected patients (HR 1.81 (1.32–2.49) P < 0.001) despite adjustment for age, gender and ethnicity. 91.3% of ICHD patients have now received both doses of SARS-CoV-2 vaccinations. Conclusions ICHD patients are at increased risk of acquiring SARS-CoV-2, with increased rates of hospitalisation and mortality. The increased mortality extends well beyond the 28 days post-infection and persists in those who have recovered. Peaks and troughs in infection rates mirrored community trends. Preliminary data indicates that the SARS-CoV-2 vaccination provides protection to ICHD patients, with ICHD case rates now comparable to that of the local population.