Objective To investigate the associations between air pollution and mortality, focusing on associations below current European Union, United States, and World Health Organization standards and guidelines. Design Pooled analysis of eight cohorts. Setting Multicentre project Effects of Low-Level Air Pollution: A Study in Europe (ELAPSE) in six European countries. Participants 325 367 adults from the general population recruited mostly in the 1990s or 2000s with detailed lifestyle data. Stratified Cox proportional hazard models were used to analyse the associations between air pollution and mortality. Western Europe-wide land use regression models were used to characterise residential air pollution concentrations of ambient fine particulate matter (PM 2.5 ), nitrogen dioxide, ozone, and black carbon. Main outcome measures Deaths due to natural causes and cause specific mortality. Results Of 325 367 adults followed-up for an average of 19.5 years, 47 131 deaths were observed. Higher exposure to PM 2.5 , nitrogen dioxide, and black carbon was associated with significantly increased risk of almost all outcomes. An increase of 5 µg/m 3 in PM 2.5 was associated with 13% (95% confidence interval 10.6% to 15.5%) increase in natural deaths; the corresponding figure for a 10 µg/m 3 increase in nitrogen dioxide was 8.6% (7% to 10.2%). Associations with PM 2.5 , nitrogen dioxide, and black carbon remained significant at low concentrations. For participants with exposures below the US standard of 12 µg/m 3 an increase of 5 µg/m 3 in PM 2.5 was associated with 29.6% (14% to 47.4%) increase in natural deaths. Conclusions Our study contributes to the evidence that outdoor air pollution is associated with mortality even at low pollution levels below the current European and North American standards and WHO guideline values. These findings are therefore an important contribution to the debate about revision of air quality limits, guidelines, and standards, and future assessments by the Global Burden of Disease.

Background Respiratory syncytial virus (RSV) is a leading cause of respiratory tract infection (RTI) in young children. Registries provide opportunities to explore RSV epidemiology and burden. Methods We explored routinely collected hospital data on RSV in children aged < 5 years in 7 European countries. We compare RSV-associated admission rates, age, seasonality, and time trends between countries. Results We found similar age distributions of RSV-associated hospital admissions in each country, with the highest burden in children < 1 years old and peak at age 1 month. Average annual rates of RTI admission were 41.3–112.0 per 1000 children aged < 1 year and 8.6–22.3 per 1000 children aged < 1 year. In children aged < 5 years, 57%–72% of RTI admissions with specified causal pathogen were coded as RSV, with 62%–87% of pathogen-coded admissions in children < 1 year coded as RSV. Conclusions Our results demonstrate the benefits and limitations of using linked routinely collected data to explore epidemiology and burden of RSV. Our future work will use these data to generate estimates of RSV burden using time-series modelling methodology, to inform policymaking and regulatory decisions regarding RSV immunization strategy and monitor the impact of future vaccines.

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We studied the secondary attack rate (SAR), risk factors, and precautionary practices of household transmission in a prospective, longitudinal study. We further compared transmission between the Alpha (B.1.1.7) variant and non-Variant of Concern (non-VOC) viruses. From May 2020 throughout April 2021, we recruited 70 confirmed COVID-19 cases with 146 household contacts. Participants donated biological samples eight times over 6 weeks and answered questionnaires. SARS-CoV-2 infection was detected by real-time RT-PCR. Whole genome sequencing and droplet digital PCR were used to establish virus variant and viral load. SARS-CoV-2 transmission occurred in 60% of the households, and the overall SAR for household contacts was 50%. The SAR was significantly higher for the Alpha variant (78%) compared with non-VOC viruses (43%) and was associated with a higher viral load. SAR was higher in household contacts aged ≥40 years (69%) than in younger contacts (40–47%), and for contacts of primary cases with loss of taste/smell. Children had lower viral loads and were more often asymptomatic than adults. Sleeping separately from the primary case reduced the risk of transmission. In conclusion, we found substantial household transmission, particularly for the Alpha variant. Precautionary practices seem to reduce SAR, but preventing household transmission may become difficult with more contagious variants, depending on vaccine use and effectiveness.

Background Bronchiolitis is the commonest cause of respiratory related hospital admissions in young children. This study aimed to describe temporal trends in bronchiolitis admissions for children under 2 years of age in Scotland by patient characteristics, socioeconomic deprivation, and duration of admission. Methods The national hospital admissions database for Scotland was used to extract data on all bronchiolitis admissions (International Classification of Disease, Tenth Revision, code J21) in children <2 years of age from 2001 to 2016. Deprivation quintiles were classified using the 2011 Scottish Index of Multiple Deprivation. Results Over the 15-year study period, admission rates for children under 2 years old increased 2.20-fold (95% confidence interval [CI], 1.4–3.6-fold) from 17.2 (15.9–18.5) to 37.7 (37.4–38.1) admissions per 1000 children per year. Admissions peaked in infants aged 1 month, and in those born in the 3 months preceding the peak bronchiolitis month—September, October, and November. Admissions from the most-deprived quintile had the highest overall rate of admission, at 40.5 per 1000 children per year (95% CI, 39.5–41.5) compared with the least-deprived quintile, at 23.0 admissions per 1000 children per year (22.1–23.9). The most-deprived quintile had the greatest increase in admissions over time, whereas the least-deprived quintile had the lowest increase. Zero-day admissions, defined as admission and discharge within the same calendar date, increased 5.3-fold (5.1–5.5) over the study period, with the highest increase in patients in the most-deprived quintile. Conclusions This study provides baseline epidemiological data to aid policy makers in the strategic planning of preventative interventions. With the majority of bronchiolitis caused by respiratory syncytial virus (RSV), and several RSV vaccines and monoclonal antibodies currently in clinical trials, understanding national trends in bronchiolitis admissions is an important proxy for determining potential RSV vaccination strategies.