論文の公開元へEpidemiology, Clinical Characteristics, and Outcomes of Influenza-Associated Hospitalizations in U.S. Children Over 9 Seasons Following the 2009 H1N1 Pandemic
概要
〔目的〕
Influenza causes significant morbidity and mortality in children, particularly among infants and young children. Since the 2009 H1N1 influenza pandemic, advances have been made in diagnostic, treatment, and prevention strategies. For example, the use of molecular influenza testing, which is more sensitive and specific than rapid antigen detection tests, has increased. Increased use of antiviral agents occurred during and after the 2009 H1N1 pandemic, and in 2012 the US Food and Drug Administration approved oseltamivir for treatment of influenza in patients >2 weeks of age. However, recent population-based data are limited regarding influenza- associated hospitalizations in children. Therefore, the aims of this study were 1) to describe rates of children hospitalized with influenza and trends in antiviral treatment and vaccination coverage in the post-2009 pandemic era; 2) to describe clinical presentation and severe outcomes of influenza-related hospitalizations in children over time; 3) to identify risk factors for severe outcomes (pneumonia, intensive care unit [ICU] admission, mechanical ventilation, and death) in children.
〔方法並びに成績〕
I identified children <18 years hospitalized with laboratory-confirmed influenza during 2010–2019 seasons through the US Influenza Hospitalization Surveillance Network (FluSurv-NET). FluSurv-NET conducts prospective, population- based surveillance for hospitalized cases of laboratory-confirmed influenza through a network of acute-care hospitals in select counties within California, Colorado, Connecticut, Georgia, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah, with a total catchment population of >27 million people (about 9% of the US population). Children residing within the catchment area were included if they had a positive influenza test within 14 days before or within 3 days after hospitalization during each influenza season. Hospitalization and in-hospital mortality rates were adjusted for influenza testing practices using a multiplier approach. Cochran-Armitage test for trend, Chi-square test or the Fisher exact test for categorical covariates. Multivariable logistic regression was conducted to evaluate risk factors for pneumonia, ICU admission, mechanical ventilation, and death.
Over 9 seasons, adjusted influenza-associated hospitalization incidence rates ranged from 10–375 per 100,000 persons each season and were highest among infants <6 months. Rates decreased with increasing age. The highest in-hospital mortality rates were observed in children <6 months (0.73 per 100,000 persons). Influenza type A predominated among hospitalized children each season while influenza B accounted for 24% of the total cases but ranged seasonally from 4% to 42% of all hospitalizations. Over time, antiviral treatment significantly increased from 56% to 85% (P <.001) and influenza vaccination rates increased from 33%to 44% (P =.003). However, early antiviral treatment (<=2 days after symptom onset) was suboptimal in children (31%–47%). The use of reverse transcription-polymerase chain reaction increased substantially, from 49% to 81%, while use of all other testing methods (e.g., rapid influenza diagnostic test) decreased substantially over time. Among the 13,235 hospitalized children, 56% were male, 34% were non-Hispanic white, and 55% had ≥1 preexisting medical condition. Fever or chills was the most common symptom reported (84.3%), followed by cough (77.8%). The frequency of reported chest pain, myalgia, sore throat, and headache increased with increasing age (P <.001). Regarding severe outcomes, 2,676 (20%) of hospitalized children were admitted to the ICU, 2,262 (17%) had pneumonia, 690 (5%) required mechanical ventilation, and 72 (0.5%) died during hospitalization. As compared with those <6 months of age, hospitalized children ≥13 years had higher odds of pneumonia (adjusted odds ratios [aOR], 2.7; 95% confidence interval [CI], 2.1–3.4), ICU admission (aOR, 1.6; 95% CI, 1.3–1.9), mechanical ventilation (aOR, 1.6; 95% CI, 1.1–2.2), and death (aOR, 3.3; 95% CI, 1.2–9.3). Children with abnormal upper airway, neurologic disease, or neuromuscular disease were more likely to be admitted to the ICU and require mechanical ventilation.
〔総括〕
Hospitalization and death rates were greatest in younger children at the population level. Among hospitalized children, however, older children had a higher risk of severe outcomes. Continued efforts to prevent and attenuate influenza in children are needed.
