Temporal and geographical variation in low carbon inhaler dispensing in England, 2016 to 2021: an ecological study.

OBJECTIVES: In 2019-2020, four national recommendations were published in the United Kingdom to encourage use of low carbon inhalers. This study aimed to investigate whether these were associated with a change in primary care dispensing in England and to explore associations between geographical variation and clinical commissioning group (CCG) characteristics. DESIGN: Ecological study using aggregated publicly available data. SETTING: All CCGs in England (March 2016 to February 2021). PARTICIPANTS: not applicable. MAIN OUTCOME MEASURES: Percentage of low carbon inhalers dispensed. RESULTS: The percentage of low carbon inhalers dispensed was 26.3% in 2020-2021 (of 8.8 million inhalers). This decreased over the study period for short-acting beta-agonist (SABA), inhaled corticosteroid (ICS) and ICS+long-acting beta-agonist (LABA) inhalers. The same trend was seen for LABA and ICS+LABA+long-acting muscarinic antagonist inhalers from 2019. The SABA and ICS classes were less often dispensed as low carbon inhalers (⁓6% versus 35-45%). Interrupted time series analyses found slight increases in low carbon inhaler percentage in the SABA, LABA and ICS classes after April 2019, which were soon erased by the long-term trend. There was also geographical variation, with the north-west, Birmingham and London consistently dispensing more low carbon inhalers. The presence of advice on climate change in CCG formularies/guidelines, the prevalence of asthma and population age profile were associated with significant variation in low carbon inhaler percentage for some classes. CONCLUSIONS: The percentage of low carbon inhalers dispensed in England remains low and continues to decrease. Greater use of low carbon inhalers is achievable, but is more likely with locally implemented initiatives.

Mucin Transiently Sustains Coronavirus Infectivity through Heterogenous Changes in Phase Morphology of Evaporating Aerosol.

Respiratory pathogens can be spread though the transmission of aerosolised expiratory secretions in the form of droplets or particulates. Understanding the fundamental aerosol parameters that govern how such pathogens survive whilst airborne is essential to understanding and developing methods of restricting their dissemination. Pathogen viability measurements made using Controlled Electrodynamic Levitation and Extraction of Bioaerosol onto Substrate (CELEBS) in tandem with a comparative kinetics electrodynamic balance (CKEDB) measurements allow for a direct comparison between viral viability and evaporation kinetics of the aerosol with a time resolution of seconds. Here, we report the airborne survival of mouse hepatitis virus (MHV) and determine a comparable loss of infectivity in the aerosol phase to our previous observations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through the addition of clinically relevant concentrations of mucin to the bioaerosol, there is a transient mitigation of the loss of viral infectivity at 40% RH. Increased concentrations of mucin promoted heterogenous phase change during aerosol evaporation, characterised as the formation of inclusions within the host droplet. This research demonstrates the role of mucus in the aerosol phase and its influence on short-term airborne viral stability.

The dynamics of SARS-CoV-2 infectivity with changes in aerosol microenvironment.

Understanding the factors that influence the airborne survival of viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aerosols is important for identifying routes of transmission and the value of various mitigation strategies for preventing transmission. We present measurements of the stability of SARS-CoV-2 in aerosol droplets (∼5 to 10 µm equilibrated radius) over timescales spanning 5 s to 20 min using an instrument to probe survival in a small population of droplets (typically 5 to 10) containing ∼1 virus/droplet. Measurements of airborne infectivity change are coupled with a detailed physicochemical analysis of the airborne droplets containing the virus. A decrease in infectivity to ∼10% of the starting value was observable for SARS-CoV-2 over 20 min, with a large proportion of the loss occurring within the first 5 min after aerosolization. The initial rate of infectivity loss was found to correlate with physical transformation of the equilibrating droplet; salts within the droplets crystallize at relative humidities (RHs) below 50%, leading to a near-instant loss of infectivity in 50 to 60% of the virus. However, at 90% RH, the droplet remains homogenous and aqueous, and the viral stability is sustained for the first 2 min, beyond which it decays to only 10% remaining infectious after 10 min. The loss of infectivity at high RH is consistent with an elevation in the pH of the droplets, caused by volatilization of CO2 from bicarbonate buffer within the droplet. Four different variants of SARS-CoV-2 were compared and found to have a similar degree of airborne stability at both high and low RH.