Impact of the COVID-19 Pandemic on Influenza Hospital Admissions and Deaths in Wales: Descriptive National Time Series Analysis.

Background: The COVID-19 pandemic and the ensuing implementation of control measures caused widespread societal disruption. These disruptions may also have affected community transmission and seasonal circulation patterns of endemic respiratory viruses. Objective: We aimed to investigate the impact of COVID-19-related disruption on influenza-related emergency hospital admissions and deaths in Wales in the first 2 years of the pandemic. Methods: A descriptive analysis of influenza activity was conducted using anonymized pathology, hospitalization, and mortality data from the Secure Anonymised Information Linkage Databank in Wales. The annual incidence of emergency hospitalizations and deaths with influenza-specific diagnosis codes between January 1, 2015, and December 31, 2021, was estimated. Case definitions of emergency hospitalization and death required laboratory confirmation with a polymerase chain reaction test. Trends of admissions and deaths were analyzed monthly and yearly. We conducted 2 sensitivity analyses by extending case definitions to include acute respiratory illnesses with a positive influenza test and by limiting admissions to those with influenza as the primary diagnosis. We also examined yearly influenza testing trends to understand changes in testing behavior during the pandemic. Results: We studied a population of 3,235,883 Welsh residents in 2020 with a median age of 42.5 (IQR 22.9-61.0) years. Influenza testing in Wales increased notably in the last 2 months of 2020, and particularly in 2021 to 39,720 per 100,000 people, compared to the prepandemic levels (1343 in 2019). The percentage of influenza admissions matched to an influenza polymerase chain reaction test increased from 74.8% (1890/2526) in 2019 to 85.2% (98/115) in 2021. However, admissions with a positive test per 100,000 population decreased from 17.0 in 2019 to 2.7 and 0.6 in 2020 and 2021, respectively. Similarly, deaths due to influenza with a positive influenza test per 100,000 population decreased from 0.4 in 2019 to 0.0 in 2020 and 2021. Sensitivity analyses showed similar patterns of decreasing influenza admissions and deaths in the first 2 years of the COVID-19 pandemic. Conclusions: Nonpharmaceutical interventions to control COVID-19 were associated with a substantial reduction in the transmission of the influenza virus, with associated substantial reductions in hospital cases and deaths observed. Beyond the pandemic context, consideration should be given to the role of nonpharmaceutical community-driven interventions to reduce the burden of influenza.

Pertussis notifications decline in Australia during COVID-19 non-pharmaceutical interventions, 2020-2021.

Background: Following implementation of coronavirus diseases 2019 (COVID-19) non-pharmaceutical interventions (NPIs) in early 2020, declines in the incidence of other respiratory pathogens have been reported. This study aimed to assess the impact of these interventions on pertussis notifications in Australia. Methods: We compared monthly national notification rates for pertussis during the first two years of the COVID-19 pandemic (2020 and 2021) to those during the three pre-pandemic years (2017 to 2019). Incidence rate ratios (IRR) by age group and jurisdiction were calculated for 2020 and 2021 compared to the mean prepandemic annual notification rate. Results: A substantial progressive decline in pertussis notifications was seen across all age groups, with all-age notification rates more than 40% lower than the pre-pandemic period in all jurisdictions in 2020, and more than 80% lower in 2021. Notification rates decreased more slowly from a lower baseline in Victoria than in other states and territories, despite the stricter, more sustained NPIs implemented in Victoria. Conclusion: The significant decrease in pertussis notifications across all jurisdictions and age groups has likely resulted in reduced infection-acquired immunity, making maintenance of high vaccine uptake, particularly among pregnant women and young infants, of key importance.

Modeling the Impact of COVID-19 Mitigation Strategies in Pennsylvania, USA.

Purpose. To estimate the impact on mortality of nonpharmaceutical interventions (NPIs) implemented early in the COVID-19 pandemic. Methods. We implemented an agent-based modified SEIR model of COVID-19, calibrated to match death numbers reported in Pennsylvania from January 2020 to April 2021 and including representations of NPIs implemented in Pennsylvania. To investigate the impact of these strategies, we ran the calibrated model with no interventions and with varying combinations, timings, and levels of interventions. Results. The model closely replicated death outcomes data for Pennsylvania. Without NPIs, deaths in the early months of the pandemic were estimated to be much higher (67,718 deaths compared to actual 6,969). Voluntary interventions alone were relatively ineffective at decreasing mortality. Delaying implementation of interventions led to higher deaths (∼9,000 more deaths with just a 1-week delay). School closure was insufficient as a single intervention but was an important part of a combined intervention strategy. Conclusions. NPIs were effective at reducing deaths early in the COVID-19 pandemic. Agent-based models can incorporate substantial detail on infectious disease spread and the impact of mitigations. Policy Implications. The model supports the importance and effectiveness of NPIs to decrease morbidity from respiratory pathogens. This is particularly important for emerging pathogens for which no vaccines or treatments exist, but such strategies are applicable to a variety of respiratory pathogens. Highlights: Nonpharmaceutical interventions were used extensively during the early period of the COVID-19 pandemic, but their use has remained controversial.Agent-based modeling of the impact of these mitigation strategies early in the COVID-19 pandemic supports the effectiveness of nonpharmaceutical interventions at decreasing mortality.Since such interventions are not specific to a particular pathogen, they can be used to protect against any respiratory pathogen, known or emerging. They can be applied rapidly when conditions warrant.

Too Many Deaths, Too Many Left Behind: A People's External Review of the U.S. Centers for Disease Control and Prevention's COVID-19 Pandemic Response.

The U.S. population has suffered worse health consequences owing to COVID-19 than comparable wealthy nations. COVID-19 had caused more than 1.1 million deaths in the U.S. as of May 2023 and contributed to a 3-year decline in life expectancy. A coalition of public health workers and community activists launched an external review of the Centers for Disease Control and Prevention's pandemic management from January 2021 to May 2023. The authors used a modified Delphi process to identify core pandemic management areas, which formed the basis for a survey and literature review. Their analysis yields 3 overarching shortcomings of the Centers for Disease Control and Prevention's pandemic management: (1) Centers for Disease Control and Prevention leadership downplays the serious impacts and aerosol transmission risks of COVID-19, (2) Centers for Disease Control and Prevention leadership has aligned public guidance with commercial and political interests over scientific evidence, and (3) Centers for Disease Control and Prevention guidance focuses on individual choice rather than emphasizing prevention and equity. Instead, the agency must partner with communities most impacted by the pandemic and encourage people to protect one another using layered protections to decrease COVID-19 transmission. Because emerging variants can already evade existing vaccines and treatments and Long COVID can be disabling and lacks definitive treatment, multifaceted, sustainable approaches to the COVID-19 pandemic are essential to protect people, the economy, and future generations.

Epidemiological Features of Hepatitis C in China From 2015 to 2021: Insights From National Surveillance Data.

The COVID-19 pandemic overwhelmed national health care systems, not least in the context of hepatitis elimination. This study investigates the effects of the pandemic response on the incidence rate, mortality rate, and case fatality rate (CFR) for hepatitis C virus (HCV) cases in China. We extracted the number of hepatitis C cases and HCV-related deaths by month and year for 2015 to 2021 in China and applied two proportional tests to analyze changes in the average yearly incidence rates, mortality rates, and CFRs for 2015 to 2020. We used the autoregressive integrated moving average model to predict these three rates for 2020 based on 2015 to 2019 HCV data. The incidence of hepatitis C decreased by 7.11% and 1.42% (P < .001) in 2020 and 2021, respectively, compared with 2015 to 2019, while it increased by 6.13% (P < .001) in 2021 relative to 2020. The monthly observed incidence in 2020 was significantly lower (-26.07%) than predicted. Meanwhile, no differences in mortality rate or CFR were observed between 2021, 2020, and 2015 to 2019. Our findings suggested that nonpharmaceutical interventions and behavioral changes to mitigate COVID-19 could have reduced hepatitis C incidence and accelerated China's implementation of a plan to eliminate HCV infection.

School closures due to seasonal influenza: a prospective data collection-based study of eleven influenza seasons-United States, 2011-2022.

Background: While numerous studies explore pandemic-associated school closures, literature is scant regarding seasonal influenza-associated closures. We previously reported summaries on COVID-19 pandemic-related school closures in the United States (US), which affected virtually all schools in the nation. The current prospective study aims to address the knowledge gap for seasonal influenza-related closures in the United States. Methods: We conducted systematic daily online searches from August 1, 2011 to June 30, 2022, to identify public announcements of unplanned school closures in the US lasting ≥1 day, selecting those that mentioned influenza and influenza-like illness (ILI) as reason for school closure (ILI-SCs). We studied ILI-SC temporal patterns and compared them with reported outpatient ILI-related healthcare visits. Findings: We documented that ILI-SCs occurred annually, with yearly totals ranging from 11 ILI-SCs in both the 2013-2014 and 2020-2021 school years to 2886 ILI-SCs in the 2019-2020 school year among more than 100,000 kindergarten through twelfth grade schools in the US. ILI-SCs occurred concurrently with widespread illness and the strongest correlations were observed during influenza A (H3N2)-dominant seasons, most notably in the 2016-2017 (Spearman rank correlation (rs) = 0.83) and the 2017-2018 (rs = 0.84) school years. ILI-SCs were heavily centered in U.S. Department of Health and Human Services Region 4 (states of Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee) [60% (6040/9166, Region 4/Total school closures)] and disproportionately impacted rural and lower-income communities. Interpretation: Outside of a pandemic, disease-related school closures are extreme and generally rare events for US schools and communities. Timely compilation of publicly available ILI-SC announcements could enhance influenza surveillance, particularly in severe influenza seasons or pandemics when ILI-SCs are prevalent. Funding: This work was supported by the U.S. Centers for Disease Control and Prevention. Co-authors (NZ, YZ, HG, AU) were or are US CDC employees, and FJ was a contractor through Cherokee Nation Operational Solutions, LLC, which supported FJ's salary, but had no additional role in the study.

Impact of Nonpharmaceutical Interventions during the COVID-19 Pandemic on the Prevalence of Respiratory Syncytial Virus in Hospitalized Children with Lower Respiratory Tract Infections: A Systematic Review and Meta-Analysis.

During the COVID-19 pandemic, nonpharmaceutical interventions (NPIs) were implemented in order to control the transmission of SARS-CoV-2, potentially affecting the prevalence of respiratory syncytial virus (RSV). This review evaluated the impact of NPIs on RSV-related hospitalizations in children during the lockdown (2020-2021) compared to the pre-pandemic (2015-2020) and post-lockdown (2021-2022) periods. In this systematic review and meta-analysis, we searched through PubMed, Scopus, and Web of Science for studies published in English between 1 January 2015 and 31 December 2022. Additionally, we conducted hand searches of other records published between 1 January 2023 and 22 January 2024. Our target population was hospitalized children aged 0-18 years with RSV-related lower respiratory tract infections confirmed through immunofluorescence, antigen testing, or molecular assays. We focused on peer-reviewed observational studies, analyzing the primary outcome of pooled RSV prevalence. A generalized linear mixed model with a random-effects model was utilized to pool each RSV prevalence. Heterogeneity was assessed using Cochran's Q and I2 statistics, while publication bias was evaluated through funnel plots and Egger's tests. We identified and analyzed 5815 publications and included 112 studies with 308,985 participants. Notably, RSV prevalence was significantly lower during the lockdown period (5.03% [95% CI: 2.67; 9.28]) than during the pre-pandemic period (25.60% [95% CI: 22.57; 28.88], p < 0.0001). However, RSV prevalence increased notably in the post-lockdown period after the relaxation of COVID-19 prevention measures (42.02% [95% CI: 31.49; 53.33] vs. 5.03% [95% CI: 2.67; 9.28], p < 0.0001). Most pooled effect estimates exhibited significant heterogeneity (I2: 91.2% to 99.3%). Our findings emphasize the effectiveness of NPIs in reducing RSV transmission. NPIs should be considered significant public health measures to address RSV outbreaks.

Is COVID-19 as Lethal as the Spanish Flu? The Australian Experience in 1919 and 2020 and the Role of Nonpharmaceutical Interventions (NPIs).

We conducted a comparative historical study to interrogate Professor Peter Doherty's warning to Australians in April 2020 that 'COVID-19 is just as lethal as the Spanish flu'. We identified the epicentres of both pandemics, namely, metropolitan Sydney in 1919 and metropolitan Melbourne in 2020 and compared the lethality of the Spanish Flu and COVID-19 in these two cities. Lethality was measured by the number and rate of hospital admissions, death rates, age-specific death rates and age-standardised mortality rates (ASMRs). Using these measures, we demonstrated the strikingly different waves of infection, their severity at various points in time and the cumulative impact of the viruses by the end of our study period, i.e., 30 September in 1919 and 2020. Hospital admissions and deaths from the Spanish Flu in 1919 were more than 30 times higher than those for COVID-19 in 2020. The ASMR per 100,000 population for the Spanish Flu was 383 compared to 7 for COVID-19: The former was about 55 times higher than the latter. These results suggest that the Spanish Flu was more lethal than COVID-19. Professor Doherty's warning was perhaps taken seriously and that partly explains the findings of this study. Containing infection in 1919 and 2020 threw the burden on nonpharmaceutical interventions (NPIs) such as 'protective sequestration' (quarantine), contact tracing, lockdowns and masks. It is likely that the persistent and detailed contact tracing scheme provides the best possible explanation for why NPIs in 2020 were more effective than in 1919 and therefore contributed to the lower lethality of the COVID-19 pandemic in its first year.

Modeling the health impact of increasing vaccine coverage and nonpharmaceutical interventions against coronavirus disease 2019 in Ghana.

Seroprevalence studies assessing community exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Ghana concluded that population-level immunity remained low as of February 2021. Thus, it is important to demonstrate how increasing vaccine coverage reduces the economic and public health impacts associated with SARS-CoV-2 transmission. To that end, this study used a Susceptible-Exposed-Presymptomatic-Symptomatic-Asymptomatic-Recovered-Dead-Vaccinated compartmental model to simulate coronavirus disease 2019 (COVID-19) transmission and the role of public health interventions in Ghana. The impact of increasing vaccination rates and decline in transmission rates due to nonpharmaceutical interventions (NPIs) on cumulative infections and deaths averted was explored under different scenarios. Latin hypercube sampling-partial rank correlation coefficient (LHS-PRCC) was used to investigate the uncertainty and sensitivity of the outcomes to the parameters. Simulation results suggest that increasing the vaccination rate to achieve 50% coverage was associated with almost 60,000 deaths and 25 million infections averted. In comparison, a 50% decrease in the transmission coefficient was associated with the prevention of about 150,000 deaths and 50 million infections. The LHS-PRCC results indicated that in the context of vaccination rate, cumulative infections and deaths averted were most sensitive to vaccination rate, waning immunity rates from vaccination, and waning immunity from natural infection. This study's findings illustrate the impact of increasing vaccination coverage and/or reducing the transmission rate by NPI adherence in the prevention of COVID-19 infections and deaths in Ghana.

Impact of the COVID-19 pandemic on the prevalence of respiratory viral pathogens in patients with acute respiratory infection in Shanghai, China.

Objective: This study aimed to evaluate the impact of nonpharmaceutical interventions (NPIs) taken to combat COVID-19 on the prevalence of respiratory viruses (RVs) of acute respiratory infections (ARIs) in Shanghai. Methods: Samples from ARI patients were collected and screened for 17 respiratory viral pathogens using TagMan low density microfluidic chip technology in Shanghai from January 2019 to December 2020. Pathogen data were analyzed to assess changes in acute respiratory infections between 2019 and 2020. Results: A total of 2,744 patients were enrolled, including 1,710 and 1,034 in 2019 and 2020, respectively. The total detection rate of RVs decreased by 149.74% in 2020. However, detection rates for human respiratory syncytial virus B (RSVB), human coronavirus 229E (HCoV229E), human coronavirus NL63 (HCoVNL63), and human parainfluenza virus 3 (HPIV3) increased by 91.89, 58.33, 44.68 and 24.29%, in 2020. The increased positive rates of RSVB, HPIV3, resulted in more outpatients in 2020 than in 2019. IFV detection rates declined dramatically across gender, age groups, and seasons in 2020. Conclusion: NPIs taken to eliminate COVID-19 had an impact on the prevalence of respiratory viral pathogens, especially the IFVs in the early phases of the pandemic. Partial respiratory viruses resurged with the lifting of NPIs, leading to an increase in ARIs infection.

The effect of nonpharmaceutical interventions on influenza virus transmission.

Background: The use of nonpharmaceutical interventions (NPIs) during severe acute respiratory syndrome 2019 (COVID-19) outbreaks may influence the spread of influenza viruses. This study aimed to evaluate the impact of NPIs against SARS-CoV-2 on the epidemiological features of the influenza season in China. Methods: We conducted a retrospective observational study analyzing influenza monitoring data obtained from the China National Influenza Center between 2011 and 2023. We compared the changes in influenza-positive patients in the pre-COVID-19 epidemic, during the COVID-19 epidemic, and post-COVID-19 epidemic phases to evaluate the effect of NPIs on influenza virus transmission. Results: NPIs targeting COVID-19 significantly suppressed influenza activity in China from 2019 to 2022. In the seventh week after the implementation of the NPIs, the number of influenza-positive patients decreased by 97.46% in southern regions of China and 90.31% in northern regions of China. However, the lifting of these policies in December 2022 led to an unprecedented surge in influenza-positive cases in autumn and winter from 2022 to 2023. The percentage of positive influenza cases increased by 206.41% (p < 0.001), with high positivity rates reported in both the northern and southern regions of China. Conclusion: Our findings suggest that NPIs against SARS-CoV-2 are effective at controlling influenza epidemics but may compromise individuals' immunity to the virus.

Public Acceptance of Measures to Control Infectious Diseases Under Different Scenarios of Severity and Transmissibility.

OBJECTIVES: Public health measures to control future epidemic threats of contagious disease, such as new variants of COVID-19, may be usefully informed by evidence about how acceptable they are likely to be, and the circumstances that condition this acceptance. This study considers how the acceptability of nonpharmaceutical interventions (NPIs) might depend on scenarios about the severity and transmissibility of the disease. METHODS: A telephone survey was conducted among a representative cross-sectional sample of the Spanish adult population. Each respondent was randomly assigned to 1 of 4 possible hypothetical scenarios about the severity and transmissibility of the disease. Participants' responses about the acceptability of 11 NPI under this scenario were analyzed using multivariate regression and latent class cluster analysis. RESULTS: A high risk of severe disease increases the acceptability of mask wearing, social distancing outdoors, lockdown, and isolation of infected cases, close contacts, and the vulnerable. A scenario in which the disease is highly transmissible would increase the acceptability of NPI that restrict movement and isolation. Most respondents would broadly accept most NPI in situations when either the severity or transmissibility was high. CONCLUSIONS: This study showed that people are more willing to accept NPIs such as mask wearing, social distancing outdoors, lockdown, and isolation in severe disease scenarios. A highly transmissible disease scenario increases the acceptability of NPIs that isolate. A majority would broadly accept NPIs to counter public health emergencies, whereas 3% to 9% of the population would always be strongly against.

On cognitive epidemic models: spatial segregation versus nonpharmaceutical interventions.

Fick's law and the Fokker-Planck law of diffusion are applied to manifest the cognitive dispersal of individuals in two reaction-diffusion SEIR epidemic models, where the disease transmission is illustrated by nonlocal infection mechanisms in heterogeneous environments. Building upon the well-posedness of solutions, threshold dynamics are discussed in terms of the basic reproduction numbers for the two cognitive epidemic models. The numerical investigation reveals that the Fokker-Planck law can better describe the diffusion of individuals by taking different dispersal strategies of exposed individuals in our cognitive epidemic models, and provides some insights on spatial segregation and nonpharmaceutical interventions: (i) spatial segregation occurs in the random diffusion model when the nonlocal infection radius is small, while it appears in the symmetric diffusion model when the radius is large; (ii) nonpharmaceutical interventions on restricting the dispersal of exposed and infected individuals do not contribute to reducing the infection proportion, but rather eliminate the disease in a region, which expands as the nonlocal infection radius increases. We additionally find that the final infection size in the random diffusion model is significantly smaller than that in the symmetric diffusion model and decreases as the nonlocal infection radius increases.

Inference under superspreading: Determinants of SARS-CoV-2 transmission in Germany.

Superspreading, under-reporting, reporting delay, and confounding complicate statistical inference on determinants of disease transmission. A model that accounts for these factors within a Bayesian framework is estimated using German Covid-19 surveillance data. Compartments based on date of symptom onset, location, and age group allow to identify age-specific changes in transmission, adjusting for weather, reported prevalence, and testing and tracing. Several factors were associated with a reduction in transmission: public awareness rising, information on local prevalence, testing and tracing, high temperature, stay-at-home orders, and restaurant closures. However, substantial uncertainty remains for other interventions including school closures and mandatory face coverings. The challenge of disentangling the effects of different determinants is discussed and examined through a simulation study. On a broader perspective, the study illustrates the potential of surveillance data with demographic information and date of symptom onset to improve inference in the presence of under-reporting and reporting delay.

Exploring the Barriers and Facilitators of Mask-Wearing Behavior During the COVID-19 Pandemic in Taiwan, the United States, the Netherlands, and Haiti: A Qualitative Study.

OBJECTIVE: This study explored the barriers and facilitators of mask-wearing behaviors during the pandemic in Taiwan, the United States, the Netherlands, and Haiti. METHODS: Face-to-face interviews were conducted in Taiwan and online interviews were conducted with participants in the United States, the Netherlands, and Haiti. RESULTS: In general, the habit of wearing a mask before coronavirus disease 2019 (COVID-19) was reported by Taiwanese participants. Additionally, Taiwanese participants perceived that wearing a mask was a social responsibility during the pandemic, suggesting that the collectivistic context might influence mask-wearing behavior. Unlike the Taiwanese population, some people in the United States and the Netherlands were reluctant to wear masks due to perceived restrictions on their freedom. Participants from Haiti mentioned that people who wore masks encountered violence, bullying, and discrimination. The results of this study suggest that political leadership and mask mandates have a strong impact on people's mask-wearing behavior. CONCLUSIONS: These findings have valuable implications for the design of diverse behavioral interventions to enhance mask-wearing as part of infectious disease preparedness. Additionally, the findings from these countries offer valuable insights for the development of effective public health interventions to enhance society's resilience during the current pandemic and future infectious disease outbreaks.

Quantified impacts of non-pharmaceutical interventions on influenza circulation during the COVID-19 pandemic in 13 African countries, 2020-2022.

Nonpharmaceutical interventions (NPIs) for SARS-CoV-2 disrupted circulation of influenza. We used data from 13 African countries and generalized linear models to identify associations between levels of NPIs, using the Oxford Stringency Index, and seasonal influenza activity, using parameters derived from 2020-2022 seasonal influenza surveillance. We found that for each step increase in school closings, the average percentage of respiratory specimens testing positive for influenza across the influenza season dropped by 20% (95% CI: 1-38%); no other NPI was significant. These findings may inform interventions to slow influenza circulation in pandemics and possibly during seasonal epidemics.

Cost effectiveness of preemptive school closures to mitigate pandemic influenza outbreaks of differing severity in the United States.

BACKGROUND: Nonpharmaceutical interventions (NPIs) may be considered as part of national pandemic preparedness as a first line defense against influenza pandemics. Preemptive school closures (PSCs) are an NPI reserved for severe pandemics and are highly effective in slowing influenza spread but have unintended consequences. METHODS: We used results of simulated PSC impacts for a 1957-like pandemic (i.e., an influenza pandemic with a high case fatality rate) to estimate population health impacts and quantify PSC costs at the national level using three geographical scales, four closure durations, and three dismissal decision criteria (i.e., the number of cases detected to trigger closures). At the Chicago regional level, we also used results from simulated 1957-like, 1968-like, and 2009-like pandemics. Our net estimated economic impacts resulted from educational productivity costs plus loss of income associated with providing childcare during closures after netting out productivity gains from averted influenza illness based on the number of cases and deaths for each mitigation strategy. RESULTS: For the 1957-like, national-level model, estimated net PSC costs and averted cases ranged from $7.5 billion (2016 USD) averting 14.5 million cases for two-week, community-level closures to $97 billion averting 47 million cases for 12-week, county-level closures. We found that 2-week school-by-school PSCs had the lowest cost per discounted life-year gained compared to county-wide or school district-wide closures for both the national and Chicago regional-level analyses of all pandemics. The feasibility of spatiotemporally precise triggering is questionable for most locales. Theoretically, this would be an attractive early option to allow more time to assess transmissibility and severity of a novel influenza virus. However, we also found that county-wide PSCs of longer durations (8 to 12 weeks) could avert the most cases (31-47 million) and deaths (105,000-156,000); however, the net cost would be considerably greater ($88-$103 billion net of averted illness costs) for the national-level, 1957-like analysis. CONCLUSIONS: We found that the net costs per death averted ($180,000-$4.2 million) for the national-level, 1957-like scenarios were generally less than the range of values recommended for regulatory impact analyses ($4.6 to 15.0 million). This suggests that the economic benefits of national-level PSC strategies could exceed the costs of these interventions during future pandemics with highly transmissible strains with high case fatality rates. In contrast, the PSC outcomes for regional models of the 1968-like and 2009-like pandemics were less likely to be cost effective; more targeted and shorter duration closures would be recommended for these pandemics.

Unique Changes in the Incidence of Acute Chest Syndrome in Children With Sickle Cell Disease Unravel the Role of Respiratory Pathogens: A Time Series Analysis.

BACKGROUND: Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). Although respiratory pathogens are frequently detected in children with ACS, their respective role in triggering the disease is still unclear. We hypothesized that the incidence of ACS followed the unprecedented population-level changes in respiratory pathogen dynamics after COVID-19-related nonpharmaceutical interventions (NPIs). RESEARCH QUESTION: What is the respective role of respiratory pathogens in ACS epidemiology? STUDY DESIGN AND METHODS: This study was an interrupted time series analysis of patient records from a national hospital-based surveillance system. All children aged < 18 years with SCD hospitalized for ACS in France between January 2015 and May 2022 were included. The monthly incidence of ACS per 1,000 children with SCD over time was analyzed by using a quasi-Poisson regression model. The circulation of 12 respiratory pathogens in the general pediatric population over the same period was included in the model to assess the fraction of ACS potentially attributable to each respiratory pathogen. RESULTS: Among the 55,941 hospitalizations of children with SCD, 2,306 episodes of ACS were included (median [interquartile range] age, 9 [5-13] years). A significant decrease was observed in ACS incidence after NPI implementation in March 2020 (-29.5%; 95% CI, -46.8 to -12.2; P = .001) and a significant increase after lifting of the NPIs in April 2021 (24.4%; 95% CI, 7.2 to 41.6; P = .007). Using population-level incidence of several respiratory pathogens, Streptococcus pneumoniae accounted for 30.9% (95% CI, 4.9 to 56.9; P = .02) of ACS incidence over the study period and influenza 6.8% (95% CI, 2.3 to 11.3; P = .004); other respiratory pathogens had only a minor role. INTERPRETATION: NPIs were associated with significant changes in ACS incidence concomitantly with major changes in the circulation of several respiratory pathogens in the general population. This unique epidemiologic situation allowed determination of the contribution of these respiratory pathogens, in particular S pneumoniae and influenza, to the burden of childhood ACS, highlighting the potential benefit of vaccine prevention in this vulnerable population.