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Background frailty imparts a higher risk for hospitalisation, mortality and morbidity due to COVID-19 infection, but the broader impacts of the pandemic and associated public health measures on community-living people with frailty are less known. Methods we used cross-sectional data from 23,974 Canadian Longitudinal Study on Aging participants who completed a COVID-19 interview (Sept–Dec 2020). Participants were included regardless of whether they had COVID-19 or not. They were asked about health, resource, relationship and health care access impacts experienced during the pandemic. Unadjusted and adjusted prevalence of impacts was estimated by frailty index quartile. We further examined if the relationship with frailty was modified by sex, age or household income. Results community-living adults (50–90 years) with greater pre-pandemic frailty reported more negative impacts during the first year of the pandemic. The frailty gradient was not explained by socio-demographic or health behaviour factors. The largest absolute difference in adjusted prevalence between the most and least frail quartiles was 15.1% (challenges accessing healthcare), 13.3% (being ill) and 7.4% (increased verbal/physical conflict). The association between frailty and healthcare access differed by age where the youngest age group tended to experience the most challenges, especially for those categorised as most frail. Conclusion although frailty has been endorsed as a tool to inform estimates of COVID-19 risk, our data suggest it may have a broader role in primary care and public health by identifying people who may benefit from interventions to reduce health and social impacts of COVID-19 and future pandemics.

Vaccinating school-aged children against influenza can reduce age-specific and population-level illness attack rates. Using a stochastic simulation model of influenza transmission, the authors assessed strategies for vaccinating children in the United States, varying the vaccine type, coverage level, and reproductive number R (average number of secondary cases produced by a typical primary case). Results indicated that vaccinating children can substantially reduce population-level illness attack rates over a wide range of scenarios. The greatest absolute reduction in influenza illness cases per season occurred at R values ranging from 1.2 to 1.6 for a given vaccine coverage level. The indirect, total, and overall effects of vaccinating children were strong when transmission intensity was low to intermediate. The indirect effects declined rapidly as transmission intensity increased. In a mild influenza season (R ¼ 1.1), approximately 19 million influenza cases could be prevented by vaccinating 70% of children. At most, nearly 100 million cases of influenza illness could be prevented, depending on the proportion of children vaccinated and the transmission intensity. Given the current worldwide threat of novel influenza A (H1N1), with an estimated R of 1.4–1.6, health officials should consider strategies for vaccinating children against novel influenza A (H1N1) as well as seasonal influenza. communicable disease control; influenza, human; influenza vaccines; mass immunization

In this paper, the authors provide estimates of 4 measures of vaccine efficacy for live, attenuated and inactivated influenza vaccine based on secondary analysis of 5 experimental influenza challenge studies in seronegative adults and community-based vaccine trials. The 4 vaccine efficacy measures are for susceptibility (VE(S)), symptomatic illness given infection (VE(P)), infection and illness (VE(SP)), and infectiousness (VE(I)). The authors also propose a combined (VE(C)) measure of the reduction in transmission in the entire population based on all of the above efficacy measures. Live influenza vaccine and inactivated vaccine provided similar protection against laboratory-confirmed infection (for live vaccine: VE(S) = 41%, 95% confidence interval (CI): 15, 66; for inactivated vaccine: VE(S) = 43%, 95% CI: 8, 79). Live vaccine had a higher efficacy for illness given infection (VE(P) = 67%, 95% CI: 24, 100) than inactivated vaccine (VE(P) = 29%, 95% CI: -19, 76), although the difference was not statistically significant. VE(SP) for the live vaccine was higher than for the inactivated vaccine. VE(I) estimates were particularly low for these influenza vaccines. VE(SP) and VE(C) can remain high for both vaccines, even when VE(I) is relatively low, as long as the other 2 measures of vaccine efficacy are relatively high.

Mathematical and computer models can provide guidance to public health officials by projecting the course of an epidemic and evaluating control measures. The authors built upon an existing collaboration between an academic research group and the Los Angeles County, California, Department of Public Health to plan for and respond to the first and subsequent years of pandemic influenza A (H1N1) circulation. The use of models allowed the authors to 1) project the timing and magnitude of the epidemic in Los Angeles County and the continental United States; 2) predict the effect of the influenza mass vaccination campaign that began in October 2009 on the spread of pandemic H1N1 in Los Angeles County and the continental United States; and 3) predict that a third wave of pandemic influenza in the winter or spring of 2010 was unlikely to occur. The close collaboration between modelers and public health officials during pandemic H1N1 spread in the fall of 2009 helped Los Angeles County officials develop a measured and appropriate response to the unfolding pandemic and establish reasonable goals for mitigation of pandemic H1N1.