Results from this active, facility-based surveillance study revealed hospitalization rates for children younger than 5 years were 1.7 to 7.1 times higher among American Indian and Alaska Native children compared to estimates from the methodologically similar US New Vaccine Surveillance Network (NVSN).
Findings from a study recently published in Pediatrics show American Indian and Alaska Native (AI/AN) children are dealing with high rates of respiratory syncytial virus (RSV)-associated acute respiratory infection (ARI) hospitalizations.
RSV-associated rates among AI/AN children have historically been some of the highest worldwide and estimates of infections are actively needed for RSV prevention strategies in this population. The study investigators conducted an active and facility-based surveillance for ARI among 324 AI/AN children under 5 years of age that had been hospitalized in Chinle, Arizona (Navajo Nation ); Whiteriver, Arizona (White Mountain Apache Tribal lands ); Anchorage, Alaska (33); and the Yukon-Kuskokwim (YK) Delta region of Alaska (136). The surveillance occurred from November 2019 to May 2020. Individuals that met the case definition of extended, severe ARI by the World Health Organization (WHO) were enrolled after parental informed consent.
Midturbinate nasal swabs specific to the study were stored in “universal transport medium” at –112° F (–80° C) until they were tested for RSV A and B at Vanderbilt University Medical Center, via single-plex, reverse-transcription quantitative polymerase chain reaction. Incidence rates per 1000 for all-cause ARI and RSV-associated hospitalization, overall and age-stratified, were calculated by the Poisson distribution (SAS v9.4, Cary, North Carolina). Numerators of enrolled children that met the case definition of ARI were adjusted to account for eligible, but not enrolled cases. The denominator was the age-stratified Indian Health Service User Population. The study was reviewed by relevant institutional review boards and the Centers for Disease Control and Prevention (CDC) while being conducted “consistent with applicable federal law and [CDC] prevention policy,” according to the authors.
In the Southwest study sites, the mean age for participants was 16.8 months, while 10.6 months was the mean age in the Alaska site (P < .01). Both household density (2.4 persons per room) and the proportion of homes without water (35.3%) was highest in YK Delta. One-third of hospitalizations associated with RSV occurred in infants younger than 6 months. All enrolled children had an RSV test result available, and 171 (53%) tested positive. For those that were positive, the mean length of stay ranged from 3.5 days in Chinle to 5.7 days in YK Delta. Supplemental oxygen among RSV-positive participants ranged from 70% at 102 feet elevation in Anchorage to 100% at 5290 feet elevation in Whiteriver.
For children less than 6 months of age, the annual RSV-associated hospitalization rates (per 1000 children) were 35.7 in Anchorage (95% CI, 20.4-62.6), 83.0 in Chinle (52.0-132.5), 70.4 in Whiteriver (36.3-136.6), and 132.2 in YK Delta (98.2-178.1). Rates for children younger than 5 years were: 7.7 in Anchorage (5.3-11.1), 27.2 in Chinle (21.3-34.4), 25.2 in Whiteriver (18.7-34.5), and 32.7 in YK Delta (26.9-39.7).
Compared to recent estimates from the methodologically similar US New Vaccine Surveillance Network (NVSN), hospitalization rates for children younger than 5 years ranged from 1.7 to 7.1 times higher for AI/AN children in the study site communities. According to the study authors, findings from the study are “the first active, population-based surveillance hospitalization data with laboratory-confirmed RSV among AI/AN children in over 15 years.” Consistent with prior studies, hospitalization and supplemental oxygen use rates for AN children in the only urban location (Anchorage), were lower than in YK Delta (the most rural), implicating socioeconomic impacts such as overcrowding, lack of running water, and poor air quality. These results corroborated findings from other studies that socioeconomic determinants of health can be a root cause of elevated RSV hospitalizations in the patient population living in tribal lands. Highlighting the importance of early-life prevention, the study revealed the greatest challenge of RSV was observed for full-term infants younger than 6 months old.
The authors noted that ARI hospitalizations fell after COVID-19 mitigation measures started in spring of 2020, meaning ARI observations from 2019 to 2020 could underestimate pre-COVID-19 rates, especially in Alaska, as respiratory season is generally extended into late April and May.
RSV-prevention products and socioeconomic determinants of health for AI/AN children are “urgently needed,” the study authors concluded, as findings from the study demonstrated this patient population continued to see high rates of RSV-associated ARI hospitalizations.
Atwell JE, Hartman RM, Parker D, et al. RSV among American Indian and Alaska Native children: 2019 to 2020. Pediatrics 2023; e2022060435. 10.1542/peds.2022-060435