ABSTRACT
Small trials have suggested that heterologous vaccination with first-dose ChAdOx1 and second-dose BNT162b2 may generate a better immune response than homologous vaccination with two doses of ChAdOx1. We used linked data from Catalonia (Spain), where those aged <60 who received a first dose of ChAdOx1 could choose between ChAdOx1 and BNT162b2 for their second dose. Comparable cohorts were obtained after exact-matching 14,325/17,849 (80.3%) people receiving heterologous vaccination to 14,325/149,386 (9.6%) receiving homologous vaccination by age, sex, region, and date of second dose. Of these, 238 (1.7%) in the heterologous and 389 (2.7%) in the homologous groups developed COVID-19 between 1st June 2021 and 11th October 2021. The resulting hazard ratio (95% confidence interval) was 0.61 [ 0.52-0.71 ], favouring heterologous vaccination, with a Number Needed to Treat of 94.9 [ 71.8 - 139.8 ]. The two groups had similar testing rates and safety outcomes. Sensitivity and negative control outcome analyses confirmed these findings. In conclusion, we demonstrate that a heterologous vaccination schedule with ChAdOx1 followed by BNT162b2 was more efficacious than and similarly safe to homologous vaccination with two doses of ChAdOx1. Most of the infections in our study occurred when Delta was the predominant SARS-CoV-2 variant in Spain. These data agree with previous phase 2 randomised trials.
Subject(s)
COVID-19ABSTRACT
The epidemiological situation generated by COVID-19 has highlighted the importance of applying non-pharmacological measures. Among these, mass screening of the asymptomatic general population has been established as a priority strategy by carrying out diagnostic tests to limit the spread of the virus. In this article, we aim to evaluate the economic impact of mass COVID-19 screenings of an asymptomatic population through a Cost-Benefit Analysis based on the estimated total costs of mass screening versus health gains and associated health costs avoided. Excluding the value of monetized health, the Benefit-Cost ratio was estimated at approximately 0.45. However, if monetized health is included in the calculation, the ratio is close to 1.20. The monetization of health is the critical element that tips the scales in favour of the desirability of screening. Screenings with the highest return are those that maximize the percentage of positives detected.
Subject(s)
COVID-19ABSTRACT
Background: Spain began vaccinating priority groups against COVID-19 with BNT162b2 in late December 2020. We report associations of vaccination with COVID-19 infection, hospitalisation, and mortality among nursing home residents, nursing home staff, and healthcare workers. Methods: We analysed three cohorts of all nursing home residents, nursing home staff, and healthcare workers in Catalonia on 27 December 2020. Data were obtained from linked primary care, RT-PCR and lateral flow test, hospital, and mortality records. Those with a pre-study COVID-19 diagnosis or no linked electronic medical records were excluded. Two doses of BNT162b2 were administered 3 weeks apart. Participants were followed until the earliest of an outcome (confirmed COVID-19 infection, hospitalisation, and mortality) or 5 March 2021. Participants could contribute data to the unvaccinated, one-dose, and two-dose groups. Analyses were conducted using time-varying Cox regression. Multivariable adjustment for imbalances in socio-demographics, comorbidity, and polypharmacy. Findings: We included 28,594 nursing home residents, 26,238 nursing home staff, and 61,951 healthcare workers, of whom 2,405, 1,584, and 2,672 received COVID-19 diagnoses; 383, 35, and 76 were hospitalised; and 409, 0, and 1 died. The adjusted hazard ratio (HR) (95% confidence interval) for COVID-19 infection after two-dose vaccination was 0·08 (0·07-0·09) for nursing home residents, 0·12 (0·10-0·15) for nursing home staff, and 0·05 (0·04-0·07) for healthcare workers. The adjusted HRs for hospitalisation and mortality after two-dose vaccination were 0·03 (0·02-0·05) and 0·02 (0·01-0·03), respectively, for nursing home residents. Nursing home staff and healthcare workers recorded insufficient events for mortality analysis. Interpretation Vaccination was associated with 85%-96% reduction in SARS-CoV-2 infection in all three cohorts, and bigger reductions in hospitalisations and mortality amongst nursing home residents for up to two months. More data are needed on the long-term effects of COVID-19 vaccines. Funding: Partially supported by National Institute of Health Research UK, We do not have any other funding acknowledgements.Declaration of Interest: None to declare. Ethical Approval: The study was approved by the Clinical Research Ethics Committee of the IDIAP Jordi Gol with reference number 21/045-PCV.