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
We aimed to assess the risk of SARS-CoV-2 infection for polling station members during the Catalan elections in February 2021. We compared the incidence 14 days after the elections between a cohort of polling station members (N= 18,304) and a control cohort paired by age, sex and place of residence. A total of 37 COVID-19 cases (0.2%) were confirmed in the members of the polling stations and 43 (0.23%) in the control group (p-value 0.576). Our study suggests that there was no greater risk of infection for the members of the polling stations.
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.
Subject(s)
COVID-19ABSTRACT
Background: To date, characterisation studies of COVID-19 have focussed on hospitalised or intensive care patients. We report for the first time on the natural history of COVID-19 disease from first diagnosis, including both outpatient and hospital care. Methods: Data was obtained from SIDIAP, a primary care records database covering >6 million people (>80% of the population of Catalonia), linked to COVID-19 RT-PCR tests, hospital emergency and inpatient, and mortality registers. All participants >=15 years, diagnosed with COVID-19 in outpatient between 15th March and 24th April 2020 (10th April for outcome studies) were included. Baseline characteristics, testing, and 30-day outcomes (hospitalisation for COVID-19 and all-cause fatality) were analysed. Results: A total of 121,263 and 95,467 COVID-19 patients were identified for characterisation and outcome studies, respectively. Women (57.8%) and age 45-54 (20.2%) were predominant. 44,709 were tested, with 32,976 (73.8%) PCR+. From 95,467 cases, a 14.6% [14.4-14.9] were hospitalised in the month after diagnosis, with male predominance (19.2% vs 11.3%), peaking at age 75-84. Overall 30-day fatality was 4.0% [95%CI 3.9%-4.2%], higher in men (4.8%) than women (3.4%), increasing with age, and highest in those residing in nursing homes (25.3% [24.2% to 26.4%]). Conclusions: COVID-19 is seen in all age-sex strata, but severe forms of disease cluster in older men and nursing home residents. Although initially managed in primary care, 15% of cases require hospitalization within a month, with overall fatality of 4%.
Subject(s)
COVID-19ABSTRACT
ObjectivesThere is uncertainty about when the first cases of COVID-19 appeared in Spain, as asymptomatic patients can transmit the virus. We aimed to determine whether influenza diagnoses masked early COVID-19 cases and, if so, estimate numbers of undetected COVID-19 cases in a large database of primary-care records covering >6 million people in Catalonia. DesignTime-series study of influenza and COVID-19 cases, using all influenza seasons from autumn-winter 2010-2011 to autumn-winter 2019-2020. SettingPrimary care, Catalonia, Spain. ParticipantsPeople registered in one of the contributing primary-care practices, covering >6 million people and >85% of the population. Main outcome measuresWeekly new cases of influenza and COVID-19 diagnosed in primary care. AnalysesDaily counts of both cases were computed using the total cases recorded over the previous 7 days to avoid weekly effects on recording practice. Epidemic curves were characterised for the 2010-2011 to 2019-2020 influenza seasons. Influenza seasons with a similar epidemic curve and peak case number as the 2019-2020 season were used to model predictions for 2019-2020. ARIMA models were fitted to the included influenza seasons, overall and stratified by age, to estimate expected case numbers. Daily excess influenza cases were defined as the number of observed minus expected cases. ResultsFour influenza season curves (2011-2012, 2012-2013, 2013-2014, and 2016-2017) were used to estimate the number of expected cases of influenza in 2019-2020. Between 4 February 2020 and 20 March 20202, 8,017 (95% CI: 1,841 to 14,718) excess influenza cases were identified. This excess was highest in the 15-64 age group. ConclusionsCOVID-19 cases may have been present in the Catalan population when the first imported case was reported on 25 February 2020. COVID-19 carriers may have been misclassified as influenza diagnoses in primary care, boosting community transmission before public health measures were taken. In future, the surveillance of excess influenza cases using widely available primary-care electronic medical records could help detect new outbreaks of COVID-19 or other influenza-like illness-causing pathogens. Earlier detection would allow public health responses to be initiated earlier than during the current crisis.