Estimating the burden of adult hospital admissions due to RSV and other respiratory pathogens in England

Respiratory syncytial virus (RSV) is a common seasonal respiratory virus and an important cause of illness among infants, but the burden of RSV disease is not well described among the older population. The objective of this study was to estimate the age-specific incidence of hospital admission among over 65 s due to respiratory illnesses attributable to RSV in England to inform optimal vaccine and therapeutic interventions. We used linear multiple regression to examine the effect of changes in weekly counts of respiratory pathogens on the weekly counts of respiratory hospital admissions. The study population was all patients aged 65 years or over admitted to English hospitals between 2nd August 2010 and 30th July 2017. RSV was estimated to account for a seasonal annual average of 71 (95% CI 52–90) respiratory admissions per 100 000 in adults age 65–74 and 251 (95% CI 186–316) admissions per 100,000 adults age 75+. Pneumococcus was the pathogen responsible for highest annual average respiratory admission with 448 (95% CI 310–587) admissions per 100,000 adults age 65–74 and 1010 (95% CI 527–1493) admissions per 100,000 adults aged 75+. This study shows that RSV continues to exert a significant burden of disease among older adults in England. These findings will support development of policy for the use of RSV therapeutics and vaccines in this age group.     

Comparative incidence and burden of respiratory viruses associated with hospitalization in adults in New York City

BackgroundAlthough the burden of influenza is well characterized, the burden of community‐onset non‐influenza respiratory viruses has not been systematically assessed. Understanding the severity and seasonality of non‐influenza viruses, including human coronaviruses, will provide a better understanding of the overall disease burden from respiratory viruses that could better inform resource utilization for hospitals and highlight the value of preventative strategies, including vaccines.MethodsFrom October 2017 to September 2019, a retrospective study was performed in a pre‐defined catchment area to estimate the population‐based incidence of community‐onset respiratory viruses associated with hospitalization. Included patients were ≥18 years old, resided in New York City, were hospitalized for ≥24 hours, and had a respiratory virus detected within 3 calendar‐days of admission. Disease burden was measured by hospital length of stay (LOS), intensive care unit (ICU) admissions, and in‐hospital mortality and compared among those with laboratory‐confirmed influenza versus those with laboratory‐confirmed non‐influenza viruses (human coronaviruses, parainfluenza viruses, respiratory syncytial virus, human metapneumovirus, and adenovirus).ResultsDuring the study period, 4232 eligible patients were identified of whom 50.9% were ≥65 years of age. For each virus, the population‐based incidence was highest for those ≥80 years of age. When compared to those with influenza viruses detected, those with non‐influenza respiratory viruses detected (combined) had higher population‐based incidence, significantly more ICU admissions, and higher in‐house mortality.ConclusionsThe burden of non‐influenza respiratory viruses for hospitalized adults is substantial. Prevention and treatment strategies are needed for non‐influenza respiratory viruses, particularly for older adults.     

Clinical characteristics and population‐based attack rates of respiratory syncytial virus versus influenza hospitalizations among adults—An observational study

BackgroundThe clinical significance of respiratory syncytial virus (RSV) among adults remains underinvestigated. We compared the characteristics and population‐based attack rates of RSV and influenza hospitalizations.MethodsDuring 2018–2020, we recruited hospitalized adults with respiratory infection to our prospective substudy at a tertiary care hospital in Finland and compared the characteristics of RSV and influenza patients. In our retrospective substudy, we calculated the attack rates of all RSV and influenza hospitalizations among adults in the same geographic area during 2016–2020.ResultsOf the 537 prospective substudy patients, 31 (6%) had RSV, and 106 (20%) had influenza. Duration of hospitalization, need for intensive care or outcome did not differ significantly between RSV and influenza patients. RSV was more often missed or its diagnosis omitted from medical record (13% vs 1% p = 0.016 and 48% vs 15%, p > 0.001). In the retrospective substudy, the mean attack rates of RSV, influenza A, and influenza B hospitalizations rose with age from 4.1 (range by season 1.9–5.9), 15.4 (12.3–23.3), and 4.7 (0.5–16.2) per 100,000 persons among 18‐ to 64‐year‐olds to 58.3 (19.3–117.6), 204.1 (31.0–345.0), and 60.4 (0.0–231.0) per 100,000 persons among 65+‐year‐olds and varied considerably between seasons.DiscussionWhile the attack rates of influenza hospitalizations were higher compared with RSV, RSV and influenza hospitalizations were similar in severity. Missing or underreporting of RSV infections may lead to underestimating its disease burden. Both RSV and influenza caused a substantial amount of hospitalizations among the elderly, stressing the need for more effective interventions.     

A multi-season national estimate of adult influenza vaccination by U.S. office-based pediatricians, 2006-2011

Please cite this paper as: Toback and Ambrose (2012) A multi‐season national estimate of adult influenza vaccination by US office‐based pediatricians, 2006–2011. Influenza and Other Respiratory Viruses 6(4), 231–234. There is no national estimate of adult influenza vaccination by US office‐based pediatricians. De‐identified patient‐level data from an electronic healthcare claims database submitted to private and public insurers were analyzed for pediatric offices from the 2006–2007 through 2010–2011 seasons. An average of 321 000 (range: 225 000–434 000) influenza vaccinations per year were estimated to be administered to adults; 52%, 22%, and 26% were given to adults 19–49, 50–64, and ≥65 years of age, respectively. Consistent with the 2010 changes to national guidelines, recommending influenza vaccination of all individuals 6 months of age and older, pediatricians appear to be providing an increasing proportion of adult vaccinations against influenza to adults 19–49 years of age (probably parents of their pediatric patients).     

Influenza vaccination in young children reduces influenza-associated hospitalizations in older adults, 2002-2006

OBJECTIVES: To assess how influenza vaccination coverage in children is related to pneumonia and influenza (P&I) in older adults and whether sociodemographic factors modify these associations. DESIGN: Approximately 5 million hospitalization records from the Centers for Medicare and Medicaid Services for four influenza years (2002–2006) were abstracted. A single‐year age distribution of rates of P&I hospitalization was estimated according to state for each influenza season; an exponential acceleration in the P&I rates with age was observed for each influenza season. State‐ and season‐specific P&I rate accelerations were regressed against the percentage of vaccinated children, older adults, or both using mixed effects models. SETTING: U.S. population, 2002 to 2006. PARTICIPANTS: U.S. population aged 65 and older. MEASUREMENTS: State‐level influenza annual vaccination coverage data in children and older adults were obtained from the National Immunization Survey and the Behavioral Risk Factor Surveillance System, respectively. RESULTS: Child influenza vaccination coverage was negatively associated with age acceleration in P&I, whereas influenza vaccination in the older adults themselves was not significantly associated with P&I in older adults. CONCLUSION: Vaccination of children against influenza may induce herd immunity against influenza for older adults and has the potential to be more beneficial to older adults than the existing policy of preventing influenza by vaccinating older adults themselves.     

Statistical estimates of respiratory admissions attributable to seasonal and pandemic influenza for Canada

Please cite this paper as: Schanzer et al. (2012) Statistical estimates of respiratory admissions attributable to seasonal and pandemic influenza for Canada. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12011. Background  The number of admissions to hospital for which influenza is laboratory confirmed is considered to be a substantial underestimate of the true number of admissions due to an influenza infection. During the 2009 pandemic, testing for influenza in hospitalized patients was a priority, but the ascertainment rate remains uncertain. Methods  The discharge abstracts of persons admitted with any respiratory condition were extracted from the Canadian Discharge Abstract Database, for April 2003–March 2010. Stratified, weekly admissions were modeled as a function of viral activity, seasonality, and trend using Poisson regression models. Results  An estimated 1 out of every 6·4 admissions attributable to seasonal influenza (2003–April 2009) were coded to J10 (influenza virus identified). During the 2009 pandemic (May–March 2010), the influenza virus was identified in 1 of 1·6 admissions (95% CI, 1·5–1·7) attributed to the pandemic strain. Compared with previous H1N1 seasons (2007/08, 2008/09), the influenza‐attributed hospitalization rate for persons <65 years was approximately six times higher during the 2009 H1N1 pandemic, whereas for persons 75 years or older, the pandemic rate was approximately fivefold lower. Conclusions  Case ascertainment was much improved during the pandemic period, with under ascertainment of admissions due to H1N1/2009 limited primarily to patients with a diagnosis of pneumonia.     

Estimating influenza‐associated mortality in New Zealand from 1990 to 2008

This study used Poisson regression modelling to estimate influenza‐associated mortality in New Zealand for 1990–2008. Inputs were weekly numbers of deaths and influenza and RSV isolates. Seasonal influenza was associated with an average of 401 medical deaths annually from 1990 to 2008, a rate of 10·6 (95% CI: 7·9, 13·3) per 100 000 persons per year, which is 17 times higher than recorded influenza deaths. The majority (86%) of deaths occurred in those 65 years and over. There was no clear decline in influenza‐associated mortality in this age group over the course of the study period.     

Contribution of Influenza Viruses,Other Respiratory Viruses and Viral Co-Infections to Influenza-like Illness in Older Adults

Influenza-like illness (ILI) can be caused by a range of respiratory viruses. The present study investigates the contribution of influenza and other respiratory viruses, the occurrence of viral co-infections, and the persistence of the viruses after ILI onset in older adults. During the influenza season 2014–2015, 2366 generally healthy community-dwelling older adults (≥60 years) were enrolled in the study. Viruses were identified by multiplex ligation–dependent probe-amplification assay in naso- and oropharyngeal swabs taken during acute ILI phase, and 2 and 8 weeks later. The ILI incidence was 10.7%, which did not differ between vaccinated and unvaccinated older adults; influenza virus was the most frequently detected virus (39.4%). Other viruses with significant contribution were: rhinovirus (17.3%), seasonal coronavirus (9.8%), respiratory syncytial virus (6.7%), and human metapneumovirus (6.3%). Co-infections of influenza virus with other viruses were rare. The frequency of ILI cases in older adults in this 2014–2015 season with low vaccine effectiveness was comparable to that of the 2012–2013 season with moderate vaccine efficacy. The low rate of viral co-infections observed, especially for influenza virus, suggests that influenza virus infection reduces the risk of simultaneous infection with other viruses. Viral persistence or viral co-infections did not affect the clinical outcome of ILI.     

Influenza and other respiratory viruses in three Central American countries

Please cite this paper as: Laguna‐Torres et al. (2011) Influenza and other respiratory viruses in three Central American countries. Influenza and Other Respiratory Viruses 5(2), 123–134. Background Despite the disease burden imposed by respiratory diseases on children in Central America, there is a paucity of data describing the etiologic agents of the disease. Aims To analyze viral etiologic agents associated with influenza‐like illness (ILI) in participants reporting to one outpatient health center, one pediatric hospital, and three general hospitals in El Salvador, Honduras, and Nicaragua Material & Methods Between August 2006 and April 2009, pharyngeal swabs were collected from outpatients and inpatients. Patient specimens were inoculated onto cultured cell monolayers, and viral antigens were detected by indirect and direct immunofluorescence staining. Results A total of 1,756 patients were enrolled, of whom 1,195 (68.3%) were under the age of 5; and 183 (10.4%) required hospitalization. One or more viral agents were identified in 434 (24.7%) cases, of which 17 (3.9%) were dual infections. The most common viruses isolated were influenza A virus (130; 7.4% of cases), respiratory syncytial virus (122; 6.9%), adenoviruses (63; 3.6%), parainfluenza viruses (57; 3.2%), influenza B virus (47; 2.7% of cases), and herpes simplex virus 1 (22; 1.3%). In addition, human metapneumovirus and enteroviruses (coxsackie and echovirus) were isolated from patient specimens. Discussion When compared to the rest of the population, viruses were isolated from a significantly higher percentage of patients age 5 or younger. The prevalence of influenza A virus or influenza B virus infections was similar between the younger and older age groups. RSV was the most commonly detected pathogen in infants age 5 and younger and was significantly associated with pneumonia (p < 0.0001) and hospitalization (p < 0.0001). Conclusion Genetic analysis of influenza isolates identified A (H3N2), A (H1N1), and B viruses. It also showed that the mutation H274Y conferring resistance to oseltamivir was first detected in Honduran influenza A/H1N1 strains at the beginning of 2008. These data demonstrate that a diverse range of respiratory pathogens are associated with ILI in Honduras, El Salvador, and Nicaragua. RSV infection in particular appears to be associated with severe disease in infants in the region.     

Record linkage study of the pathogen‐specific burden of respiratory viruses in children

Background

Reliance on hospital discharge diagnosis codes alone will likely underestimate the burden of respiratory viruses.

Objectives

To describe the epidemiology of respiratory viruses more accurately, we used record linkage to examine data relating to all children hospitalized in Western Australia between 2000 and 2012.

Patients/Methods

We extracted hospital, infectious disease notification and laboratory data of a cohort of children born in Western Australia between 1996 and 2012. Laboratory records of respiratory specimens collected within 48 hours of admission were linked to hospitalization records. We calculated the frequency and rates of virus detection. To identify groups where under‐ascertainment for respiratory viruses was greatest, we used logistic regression to determine factors associated with failure to test.

Results and conclusions

Nine percentage of 484 992 admissions linked to a laboratory record for respiratory virus testing. While 62% (n = 26 893) of laboratory‐confirmed admissions received respiratory infection diagnosis codes, 38% (n = 16 734) had other diagnoses, notably viral infection of unspecified sites. Of those tested, incidence rates were highest for respiratory syncytial virus (247 per 100 000 child‐years) followed by parainfluenza (63 per 100 000 child‐years). Admissions among older children and those without a respiratory diagnosis were associated with failure to test for respiratory viruses. Linked data can significantly enhance diagnostic codes when estimating the true burden of disease. In contrast to current emphasis on influenza, respiratory syncytial virus and parainfluenza were the most common viral pathogens among hospitalized children. By characterizing those failing to be tested, we can begin to quantify the under‐ascertainment of respiratory viruses.     

Community respiratory virus infections following lung transplantation

Abstract: Respiratory infections remain a significant cause of morbidity and mortality after lung transplantation. In addition to cytomegalovirus, the community respiratory viruses such as respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus, and adenovirus, are important causes of infection in transplant recipients, often involve the lower respiratory tract, and may be associated with significant morbidity and mortality. In this review, we summarize the current state of knowledge regarding the epidemiology, clinical manifestations, diagnosis, treatment and outcomes associated with RSV, PIV, influenza virus, and adenovirus infections in lung transplant recipients.     

Hospitalization Incidence,Mortality, and Seasonality of Common Respiratory Viruses Over a Period of 15 Years in a Developed Subtropical City

Information on respiratory viruses in subtropical region is limited.Incidence, mortality, and seasonality of influenza (Flu) A/B, respiratory syncytial virus (RSV), adenovirus (ADV), and parainfluenza viruses (PIV) 1/2/3 in hospitalized patients were assessed over a 15-year period (1998–2012) in Hong Kong.Male predominance and laterally transversed J-shaped distribution in age-specific incidence was observed. Incidence of Flu A, RSV, and PIV decreased sharply from infants to toddlers; whereas Flu B and ADV increased slowly. RSV conferred higher fatality than Flu, and was the second killer among hospitalized elderly. ADV and PIV were uncommon, but had the highest fatality. RSV, PIV 2/3 admissions increased over the 15 years, whereas ADV had decreased significantly. A “high season,” mainly contributed by Flu, was observed in late-winter/early-spring (February–March). The “medium season” in spring/summer (April–August) was due to Flu and RSV. The “low season” in late autumn/winter (October–December) was due to PIV and ADV. Seasonality varied between viruses, but predictable distinctive pattern for each virus existed, and temperature was the most important associating meteorological variable.Respiratory viruses exhibit strong sex- and age-predilection, and with predictable seasonality allowing strategic preparedness planning. Hospital-based surveillance is crucial for real-time assessment on severity of new variants.     

Incidence and morbidity of human metapneumovirus and other community‐acquired respiratory viruses in lung transplant recipients

A. Weinberg, D.M. Lyu, S. Li, J. Marquesen, M.R. Zamora. Incidence and morbidity of human metapneumovirus and other community‐acquired respiratory viruses in lung transplant recipients
Transpl Infect Dis 2010: 12: 330–335. All rights reserved. Abstract: To determine the role of human metapneumovirus (HMPV) in respiratory tract infections (RTIs) of lung transplant recipients, 60 patients were prospectively enrolled in this study spanning from September 2005 to November 2007. Community‐acquired respiratory viruses (CARVs) were identified by polymerase chain reaction and tissue culture in respiratory secretions. Of 112 RTIs, 51 were associated with ≥1 CARV, including 7 HMPV, 13 respiratory syncytial virus (RSV), 19 parainfluenza virus 1, 2, or 3 (PIV), 16 influenza A or B (FLU), and 3 human rhinoviruses (HRV). Sixteen CARV‐RTIs had multiple pathogens. While the standard protocol was to admit all paramyxoviral RTIs for inhaled ribavirin, 16% CARV‐RTIs required hospitalization because of the severity of their respiratory compromise, including 25% of HPMV‐single‐agent RTI, 38% of RSV single‐agent RTI, 10% of PIV‐single‐agent RTI, and 19% of multiple‐agent RTIs. None of those with non‐CARV RTIs required hospitalization. The incidence of clinically diagnosed acute graft rejection in the first 2 months after an RTI varied from 0 for single‐agent HRV to 88% for single‐agent RSV (25% for single‐agent HMPV). A new diagnosis of chronic graft rejection in the first year after an RTI was made in approximately 25% of the RTIs and did not significantly vary with the etiologic agent. No deaths occurred during this study. In conclusion, HMPV was associated with 6% of the RTIs in lung transplant recipients and its morbidity was similar to the average moribidity of CARVs.     

The relative clinical impact of 2009 pandemic influenza A (H1N1) in the community compared to seasonal influenza in the Netherlands was most marked among 5-14 year olds

Please cite this paper as: van Gageldonk‐Lafeber et al. (2011) The relative clinical impact of 2009 pandemic influenza A (H1N1) in the community compared to seasonal influenza in the Netherlands was most marked among 5–14 year olds. Influenza and Other Respiratory Viruses 5(6), e513–e520. Background So far, most pandemic influenza reports were based on case studies focusing on severe disease. For public health policy, it is essential to consider the overall impact of the pandemic, including mild diseases. Objectives The aim of our study is to gain insight into the epidemiology of 2009 pandemic influenza in the community and to estimate the relative impact of pandemic compared to seasonal influenza. Methods The relative impact of pandemic influenza in the general population was assessed as the influenza‐like illness (ILI) incidence during the pandemic season compared with that during regular seasons. Influenza‐like illness incidences and virus diagnostics were derived from continuous sentinel surveillance systems. The incidence of hospital admissions, based on the mandatory notification of pandemic influenza, was used to relate the impact of severe disease to that in the community. Results The overall incidence of general practitioners‐attended ILI was 96 consultations per 10 000 persons. Highest incidences were reported in children and lowest in persons aged ≥65 years. For 5–14 year olds, the incidence during the pandemic was higher than during all preceding seasons. Samples originating from 5 to 19 year olds were statistically significant more often positive for pandemic influenza A (H1N1) 2009 virus as compared with samples from 0 to 4 year olds. Moreover, the incidence of hospital admission owing to pandemic influenza was highest in the youngest children. Conclusions Our study showed that while the absolute incidences of 2009 pandemic influenza were highest in children aged 0–4 years, the relative clinical impact in the community compared to seasonal influenza in previous years was most noticeable in healthy children 5–14 years of age.