Influenza and Other Respiratory Viruses最新文献

Background

Disruptions in respiratory syncytial virus (RSV) activity were observed in different countries following the 2009 influenza pandemic. Given the limited use of non-pharmaceutical interventions, these disruptions provide an opportunity to probe viral interference due to the out-of-season epidemics. The objectives of the study are twofold: to characterize atypical RSV activity in the United States (US) and to explore the mechanisms underlying changes in RSV epidemics following the pandemic.

Methods

Laboratory-confirmed RSV cases across 10 US regions from June 2007 to July 2019 were analyzed. A dynamic time warping method was used to characterize RSV activity in different seasons. A two-pathogen model was constructed to explore viral interference mechanisms. A sampling–importance–resampling method was applied to estimate the effects of viral interference.

Results

We found that RSV activity was reduced following the influenza pandemic in the 2009/10 season across all regions in the US. By contrast, we found an enhanced but delayed RSV epidemic across the US in the 2010/11 season. Using a mathematical model, we explored three potential viral interference mechanisms that could explain the change of RSV activity following the pandemic. The pandemic influenza may interfere with RSV to reduce susceptibility to RSV coinfection, or shorten the RSV infectious period, or decrease RSV infectivity in co-infections.

Conclusions

This study provides statistical evidence for atypical RSV seasons following the influenza pandemic in the US and sheds light on viral interference mechanisms affecting RSV epidemics, offering a model-fitting framework for analyzing surveillance data at the population level.

Background

The COVID-19 pandemic and associated non-pharmaceutical interventions significantly altered the epidemiology of respiratory pathogens. This study aimed to evaluate the changes in the prevalence and distribution of respiratory pathogens among children with acute respiratory infections (ARIs) before and after the relaxation of COVID-19 restrictions in Shenzhen, China.

Methods

This study enrolled hospitalized children with ARIs in Shenzhen Children's Hospital during the COVID-19 epidemic and those post-epidemic period. Demographic data of the patients enrolled were retrieved from the Shenzhen Children's Hospital electronic patient dossiers. Nasopharyngeal swabs were collected and detected for 11 pathogens, and epidemiological trends were analyzed by age, season, and pathogen distribution.

Results

A total of 40,174 children with ARIs were enrolled, including 14,816 during the COVID-19 epidemic and 25,358 in the post-epidemic period. Hospital admissions for ARIs increased by 71.2% in the post-epidemic period. The median age of patients rose from 27 to 47 months. Pathogen detection rates increased significantly from 59.3% during epidemic period to 73.0% in post-epidemic period (p < 0.001), with co-detection (≥ 2 pathogens) rising from 10.5% to 21.2%. The dominant pathogens shifted from HRV, RSV, and HPIV during COVID-19 epidemic to HRV, MP, and RSV in the post-epidemic. Notably, MP detection rates surged from 1.69% to 20.87%, while RSV and HPIV peaks were replaced by MP and HMPV in winter.

Conclusion

The relaxation of COVID-19 non-pharmaceutical interventions led to a significant rebound in ARIs among children, with altered pathogen dominance and increased co-detection.

Background

The impact of the simultaneous circulation of COVID-19 and seasonal influenza, termed the “Twindemic,” on absenteeism among healthcare workers (HCWs), particularly those with children, remains unclear. We aimed to investigate the associations of living with school-aged children with the risk of SARS-CoV-2 and influenza infections and the risk of absenteeism due to own- or family-related COVID-19 or influenza events among HCWs during the Twindemic.

Methods

This prospective study followed 1473 HCWs at a tertiary hospital in Tokyo from December 2023 to March 2024. We tracked the incidence of SARS-CoV-2 and influenza infections and absenteeism due to COVID-19 or influenza-related family events. We estimated the hazard ratios (HRs) or incidence rate ratios (IRRs) of these outcomes across living arrangements, focusing on cohabitation with school-aged children.

Findings

HCWs living with younger school-aged children (≤ third grade of junior school) had a higher risk of SARS-CoV-2 and influenza infections, with HRs [95% confidence interval (CI)] of 1.90 [0.97–3.69] and 2.42 [1.04–5.66], respectively, compared with those living with cohabitants without school-aged children. Additionally, they showed a higher IRR [95% CI] for absenteeism due to family-related events (10.9 [4.88–24.5]), and their overall IRR [95% CI] of absenteeism due to own/family-related events was 3.76 [2.59–5.46].

Conclusion

The Twindemic has heightened absenteeism risks among HCWs with school-aged children, emphasizing the need for targeted support to help HCWs manage both their professional duties and family responsibilities during such challenging times.

Background

Respiratory syncytial virus (RSV) morbidity and mortality in adults are often underestimated due to nonspecific symptoms, limited standard-of-care testing and lower diagnostic testing sensitivity compared with children. To accurately evaluate the RSV disease burden among adults in Australia, we conducted a model-based study to estimate RSV-attributable cardiorespiratory hospitalisation incidence and mortality rate.

Methods

A quasi-Poisson regression model was used to estimate RSV-attributable cardiorespiratory, respiratory and cardiovascular events, using weekly hospitalisation and mortality data from 2010 to 2019, accounting for periodic and aperiodic time trends and viral activity and allowing for potential overdispersion. The time-series model compared the variability in confirmed RSV events alongside variability in all-cause cardiorespiratory events identified from ICD-10-AM codes to estimate the number of RSV-attributable events, including undiagnosed RSV-related events.

Results

RSV-attributable incidence of cardiorespiratory hospitalisations increased with age and was highest among adults ≥ 65 years (329.5–386.6 cases per 100,000 person-years), nine times higher than in adults 18–64 years. The estimated incidence of RSV-attributable respiratory hospitalisations in adults ≥65 years (219.7–247.8 cases per 100,000 person-years) was 35-fold higher than in adults 18–64 years. RSV-attributable deaths accounted for 4% to 6% of cardiorespiratory deaths in adults ≥ 65 years, with RSV-attributable mortality rates ranging from 65.6 to 77.6 deaths per 100,000 person-years and respiratory mortality rates ranging from 20.3 to 24.0 deaths per 100,000 person-years, both 70-fold higher than in adults 18–64 years.

Conclusions

This study identified substantial RSV-associated morbidity and mortality among Australian adults and is the first study to report RSV-attributable mortality rates for Australia that account for untested events.

Background

Following the 2021–2022 avian influenza panzootic in birds and wildlife, seasonal influenza vaccines have been advised to occupationally high-risk groups to reduce the likelihood of coincidental infection in humans with both seasonal and avian influenza A viruses.

Methods

We developed and launched a questionnaire aimed at poultry workers and people in direct contact with birds to understand awareness and uptake of seasonal influenza vaccination. We collected responses in-person at an agricultural trade event and online.

Findings

The questionnaire was completed by 225 individuals from across the United Kingdom. The most commonly reported reason for vaccination was protection against seasonal influenza (82%, 63 of 77). Nearly, all individuals aged ≥65 years reported that the vaccine was recommended for them (24 of 28). There was no difference in recommendation for occupational groups. Most vaccinees were aged over 60 years (60%, 29 of 48); however, coverage was lower than expected in the ≥ 65 target group. Vaccination in those exposed to avian influenza was low (32%, 9 of 28). Not having enough time was the single most reported reason for not getting vaccinated in those intending to. Individuals unintending to be vaccinated perceived natural immunity to be better than receiving the vaccine as well as lack of awareness and time.

Conclusions

Our findings suggest that targeted campaigns in occupationally exposed groups need to be undertaken to improve communication of information and access to vaccine clinics. We recommend co-production methods to optimise this public health strategy for increased knowledge and future vaccine uptake.

Background

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in children less than 5 years of age worldwide. In the United States, RSV commonly causes hospitalization in young children and is the leading cause of hospitalizations in infants. As new RSV immunizations become available, burden estimates are critical to guide the implementation of recommendations and quantify impact.

Methods

We estimated RSV-associated hospitalization rates at a large US pediatric medical center during an 8-year period using five approaches, namely, estimation directly from active and passive surveillance systems, both a crude and stratified capture–recapture analysis of data from both systems, and estimation based on discharge diagnosis codes. The stratified analysis was performed to ensure adherence with the capture–recapture methodology assumption that samples are independent and participants have an equal probability of being observed within each system.

Results

Overall, estimated RSV-associated hospitalization rates per 1000 children were 4.0 (2.5, 6.1) based on adjusted estimates from active surveillance, 1.7 (2.1, 4.4) from passive surveillance, 7.9 (5.7, 13.0) from crude capture–recapture analysis, 5.0 (3.8, 7.2) from the stratified capture–recapture, and 4.4 (4.0, 4.9) from discharge diagnosis codes.

Conclusions

Each method has limitations and inherent biases that may impact the estimation of the burden of RSV. Capture–recapture analysis may be a useful tool to estimate the burden of RSV, but needs to be adjusted to account for possible violation of the assumptions of independence and equal probability of capture to ensure accurate approximation of disease burden and avoid over estimation.

Background

The patterns of circulation and burden of influenza and respiratory syncytial virus (RSV) in Singapore are affected by the COVID-19 pandemic containment measures. These patterns in relation to SARS-CoV-2 in a post-pandemic era are unclear.

Methods

Using data from 2015 to 2023, we estimated excess influenza-, RSV- and SARS-CoV-2-associated hospitalisation in Singapore, adjusted for rhinovirus/enterovirus activity in generalised additive models. The data include pneumonia and influenza (P&I) hospitalisation from a national inpatient database and a community-wide acute respiratory infection (ARI) sentinel surveillance programme, stratified by age groups.

Results

Across all age groups, the proportion of hospitalisation associated with influenza, SARS-CoV-2 and RSV was 13.2% (95% CI 5.0%–21.6%), 19.3% (95% CI 13.8%–25.0%) and 4.0% (95% CI 0.9%–12.1%) in 2023, respectively. From 2019 to 2023, all-age influenza-associated hospitalisation declined from 264.4 per 100,000 person-years (95% CI 214.2–313.2) to 203.7 per 100,000 person-years (95% CI 76.8–333.6). In contrast, all-age RSV-associated hospitalisation after the pandemic was 62.2 per 100,000 person-years (95% CI 13.8–186.9), similar to pre-pandemic observations. Peak seasonal influenza occurred 3–8 weeks later as compared with the time of pre-pandemic peak influenza activity.

Conclusion

The overall burden of influenza has declined after the COVID-19 pandemic and its burden is comparable with SARS-CoV-2. Furthermore, shifts in the timing of peak influenza activity suggest a potential need to review the timing of vaccine recommendations in Singapore.

Objectives

This study aimed to estimate the incidence of respiratory syncytial virus (RSV) infections in US inpatient and outpatient settings.

Methods

We established national cohorts of privately insured children < 5 years (2011–2019) to estimate annual and seasonal incidences of lower respiratory tract infection (LRTI), RSV-LRTI, and RSV acute respiratory infection (RSV-ARI), stratified by age and high-risk conditions per American Academy of Pediatrics definitions. Sensitivity analyses varied episode definitions and assessed the impact of immunoprophylaxis and RSV under-ascertainment.

Results

Among 6,767,107 children, annual RSV-LRTI rates dropped with increasing age in both inpatient (7.9 for age < 1 year to 0.2 for age 4 per 1000 person-years) and outpatient settings (48.3 to 1.6). Most RSV-ARI (~80%–90%) was RSV-LRTI. RSV-LRTI accounted for > half of LRTI hospitalizations among infants (7.9 RSV-LRTI versus 14.7 LRTI) and for ~20% outpatient LRTI (48.3 versus 250.3), but this contribution declined with older age. Outpatient RSV-LRTI was > 5 times inpatient rates.

Inpatient RSV-LRTI rates dropped consistently with increasing gestational age (GA) (35.6 for GA < 29 weeks versus 7.6 for term infants), while outpatient rates were similar across GA groups (54.0 versus 51.6). Infants with Down syndrome had the highest RSV-LRTI rates, and any high-risk group had rates >2 times higher than healthy term infants. Across all strata, seasonal rates were > 2 annual rates. Modeling suggested that claims data captured 42% of all RSV episodes.

Conclusion

This study provides national, population-based estimates of medically attended RSV infections across age groups and high-risk strata. Results allow granular assessments of disease burden to guide recommendations for new RSV prevention strategies.