Respiratory Syncytial Virus (RSV) is a major cause of acute respiratory tract infections (ARTIs) and can trigger outbreaks in vulnerable settings such as nursing homes, pediatric wards, and neonatal intensive care units. This meta-analysis aims to investigate the prevalence, outbreak size, attack rate, and case fatality rate (CFR) of RSV outbreaks reported globally from 1960 to 2025, as well as to assess variations by geographic region, age group, season, outbreak setting, and viral genotypes. We compiled a global RSV outbreak dataset by searching publications from database inception to January 31, 2025, across MEDLINE, Embase, Global Health, CINAHL, Web of Science, LILACS, OpenGrey, CNKI, Wanfang, and ChongqingVIP. Studies were eligible if they reported data on laboratory-confirmed HRSV outbreaks in any settings (i.e., hospitals, communities, schools, kindergartens, and long-term care facilities) and among all age groups (pediatric and adult patients). There were no language restrictions (English or Chinese). Studies were excluded if they lacked a clear or inconsistent definition or based solely on serology for RSV diagnosis. We used a standardized form to extract publication characteristics, study location, and outbreak and participant information (prevalence, date and season, age, setting, attack rate, CFR, and genotypes). Two authors independently assessed eligibility, with discrepancies being resolved through discussion with a third author. Random-effects models were used to generate pooled estimates with 95% confidence intervals (CIs). The estimated annual percentage change (EAPC) was calculated to assess temporal trends in prevalence, attack rate, and CFR of RSV outbreaks. The study was registered with PROSPERO under CRD42022303015. A total of 72 articles from 25 countries were included, reporting 82 RSV outbreaks worldwide involving 2282 cases. Among these, 28 studies (reporting 30 outbreaks) provided information on RSV-related deaths, while 32 studies provided RSV genotype information. The highest outbreak rates were observed in Europe, the Americas, and Asia, especially in the winter season. The most common settings were neonatal intensive care units (30.49%), hematology wards/cancer centers (24.39%), and neonatal wards (15.85%). The median outbreak size was 13 cases (range: 3-588), and RSV-B was the most common genotype (46.88%, 15/32). RSV outbreak reporting increased from 3 in 1960-1970 to 37 in 2010-2025, while the overall CFR decreased from 12.29% (95% CI: 2.51-25.95) in the 1990s to 1.24% (95% CI: 0.01-3.73) in 2010-2025 (p < 0.05). The CFRs were the highest among the elderly (9.24%, 95% CI: 2.75-18.07), in hematology wards/cancer centers (7.56%, 95% CI: 2.56-14.15), and in RSV-A and B co-infections (6.31%, 95% CI: 0.02-18.60). The global pooled attack rate was 35.78% (95% CI: 29.16-42.67), higher in children-related outbreaks (42.29%, 95% CI: 34.53-50.23), neonatal wards (44.67%, 95% CI: 31.76-57.92), and RSV-B genotype studies (46.95%, 95% CI: 35.20-58.87). RSV outbreaks have contributed significantly to global morbidity since the 1960s, with increasing reports over time. While the CFRs have decreased, they remain high in certain subgroups based on age, genotype, and outbreak setting. The pooled attack rate remains substantial, particularly in healthcare settings involving RSV-B genotypes and among immunosuppressed populations. This meta-analysis underscores the importance of targeted vaccination and treatment strategies for controlling RSV outbreaks worldwide in the future. This study was supported by the Zhejiang Provincial Program for the Cultivation of High-Level Innovative Health Talents and Zhejiang Provincial Disease Control and Prevention Administration (2025JK008) and the Key Program of Health Commission of Zhejiang Province/Science Foundation of National Health Commission (WKJ-ZJ-2523).

Given the rapid rate of global spread and consequently healthcare costs related to influenza, surveillance plays an important role in monitoring the emerging pandemics in China. However, the characteristics of influenza in Southeast of China haven’t been fully studied. Our study use the surveillance data collected from 16 sentinel hospitals across Zhejiang Province during March 2011 through June 2015, including the demographic information and respiratory specimens from influenza-like illness (ILI) patients and severe acute respiratory illness (SARI) patients. As analysis results, most SARI and ILI patients were in the age group of 0–4 years old (62.38% of ILI and 71.54% of SARI). The respiratory specimens have statistically significantly higher positive rate for influenza among ILI patients than that among SARI patients (p < 0.001). The comparison between ILI patients and SARI patients shows no statistically significantly difference in detecting influenza virus type and influenza A virus subtype. The SARI and ILI patients were found to be positively correlated for overall positive rate (r = 0.63, p < 0.001), the weekly percentage of A(H1N1)pdm09 (r = 0.51, p < 0.001), influenza B virus (r = 0.17, p = 0.013), and A/H3N2 (r = 0.43, p < 0.001) among all the positive numbers. Our study demonstrated that the activities of influenza virus, including its subtypes, had a similar temporal pattern between ILI and SARI cases.

The Yangtze River Delta is one of the top five Chinese regions affected by COVID-19, as it is adjacent to Hubei Province, where COVID-19 first emerged. We investigated the impact of COVID-19 non-pharmaceutical interventions (NPIs) on changes in respiratory infectious diseases (RIDs) incidence and air quality in the Yangtze River Delta by constructing two proportional tests and fitting ARIMA and linear regression models. Compared with the pre-COVID-19 period, the average monthly incidence of seven RIDs decreased by 37.80% (p < 0.001) and 37.11% (p < 0.001) during the COVID-19 period and the post-vaccination period, respectively, in Shanghai, and decreased by 20.39% (p < 0.001) and 22.86% (p < 0.001), respectively, in Zhejiang. Similarly, compared with the pre-COVID-19 period, the monthly overall concentrations of six air pollutants decreased by 12.7% (p = 0.003) and 18.79% (p < 0.001) during the COVID-19 period and the post-vaccination period, respectively, in Shanghai, and decreased by 12.85% (p = 0.008) and 15.26% (p = 0.001), respectively, in Zhejiang. Interestingly, no significant difference in overall incidence of RIDs and concentrations of air quality was shown between the COVID-19 period and the post-vaccination period in either Shanghai or Zhejiang. This study provides additional evidence that the NPIs measures taken to control COVID-19 were effective in improving air quality and reducing the spread of RIDs. However, a direct causal relationship has not been established.

What is already known about this topic? Human respiratory syncytial virus (HRSV) coinfection with other respiratory pathogens frequently occurs in young children with acute respiratory illness. However, the epidemiological patterns and associated disease burden of HRSV coinfections in pediatric populations remain poorly characterized. What is added by this report? Analysis of hospitalized children under 5 years in Zhejiang Province from 2018 to 2023 revealed that 20.4% experienced HRSV coinfections, with bacterial coinfections substantially exceeding viral coinfections (14.1% vs. 5.3%). M. pneumoniae and S. pneumoniae emerged as predominant bacterial copathogens, while human rhinovirus and cytomegalovirus were the most prevalent viral coinfection agents. HRSV coinfections were associated with significantly higher disease burden compared to HRSV monoinfection [median expense: 4,971.4 Chinese Yuan (CNY) vs. 4,649.1 CNY; P<0.05]. What are the implications for public health practice? Implementation of comprehensive prevention strategies, including vaccination programs, nonpharmaceutical interventions, and enhanced surveillance of multiple respiratory pathogens, is essential to reduce HRSV coinfections and their associated disease burden during periods of high respiratory pathogen circulation.