RSV, Influenza Diagnosis Likely Predicted by Age

Age was an effective predictor of the diagnosis of respiratory syncytial virus (RSV) and influenza, according to a new study published in International Journal of Pediatric Research.

RSV and influenza are common respiratory infections in children, with RSV accounting for 58,000 hospitalizations and 100 to 300 deaths annually in the United States in children 5 years and younger. Although all pediatric populations are at an increased risk for RSV, studies have not been conducted to assess other predictors. This study aimed to “evaluate child characteristics, maternal characteristics, demographic, and community-level socioeconomic factors as potential determinants of RSV and influenza diagnosis of all severity types.”

Children 14 years and younger who were tested for RSV and influenza at the University of Rochester Medical Center in Rochester, New York, between October 1, 2012, and May 31, 2019, were eligible for the test-negative case-control study. Only tests conducted between October 1 and May 31 of each year were included. All children were categorized into 2 groups, case and controls, that were based on their test results. Children who served as a case who also tested negative at a different point in the 7-year span could also be included as a control. Data were extracted from medical records.

Predictors that were included in the analysis included age at testing, sex, race, insurance status, birthweight, parity, maternal age, respiratory season of testing, breastfeeding status during delivery hospitalization, smoking, and community-level characteristics. The association between RSV and influenza and all predictors were individually examined.

The study included 1808 children aged 0 to 14 years; 432 children tested positive for RSV and 296 tested positive for influenza. The children included identified as White (51%), Black (36%), other race (13%), and Hispanic (12%).

Children with an RSV diagnosis were younger, male, non-White, and not exclusively breastfed at delivery; had a nontypical birthweight; and had mothers who smoked before and/or after pregnancy compared with controls. Children with influenza were older, non-White race, and Hispanic; had a typical birthweight; had a nonprivate insurance type; and had younger mothers who smoked before and/or after pregnancy compared with controls.

The median (IQR) age of children who were infected with RSV was 1.05 (0.42-2.06) years, and case ages ranged from 2 weeks to 11.4 years. Children had a 15% decreased risk of RSV diagnosis for every year increase in age; children younger than 6 months had a greater than 150% increased risk of RSV (95% CI, 8.61-27.05).

Children infected with influenza had a median age of 5.15 (2.22-7.94) years, with case ages ranging from 1.5 months to 14.97 years. There was a 20% increased risk of influenza diagnosis for every year older (95% CI, 1.16-1.24). The proportion of positive RSV tests and influenza tests corroborated this, as positive RSV tests decreased with increasing age and positive influenza tests increased with increasing age.

An adjusted multivariable logistic regression model found that children who were younger than 6 months had a 14% increased risk of diagnosis of RSV compared with children aged 5 years and older (95% CI, 7.89-25.56). RSV was also more likely in children who had a birthweight outside of the typical range. Children who identified as Black had 12% greater odds of RSV compared with White children (95% CI, 0.81-1.56).

Children’s age and private insurance status were found to be predictors for diagnosis of influenza. Children 6 months or younger had 90% reduced odds of influenza (95% CI, 0.06-0.17), and children with self-pay insurance had 2.12 times the odds of influenza diagnosis compared with those who had private insurance (95% CI, 1.13-4.00).

Vaccine information for influenza was missing, and there was also a lack of clinical predictors and specific study samples included in this study, marking limitations on these findings.

The researchers concluded that age was the strongest predictor of infection for RSV and influenza based on the results of this study.

Reference

Oktapodas Feiler M, Yucel R, Liu Z, et al. Trends and non-clinical predictors of respiratory syncytial virus (RSV) and influenza diagnosis in an urban pediatric population. Int J Pediatr Res. Published online April 27, 2023. doi:10.23937/2469-5769/1510112