RSV prophylaxis during RSV season includes which infant group as a criterion?

• A. Born at ≤28 weeks gestation and <12 months of age at start of RSV season
• B. Infants less than 12 months with chronic lung disease requiring medical therapy
• C. Infants less than 12 months with hemodynamically significant congenital heart disease
• D. Infants and children less than 24 months with chronic lung disease necessitating medical therapy within 6 months prior to the RSV season

Answer: (D)

The key idea is that RSV prophylaxis with palivizumab is targeted to infants and young children who have conditions that put them at high risk for severe RSV disease, and it specifically uses recent medical therapy needs to determine eligibility during the RSV season.

Among the groups, those with chronic lung disease that required medical therapy within the 6 months before the RSV season are at particularly high risk for severe RSV and hospitalization. Extending the age up to 24 months for this group recognizes that chronic lung disease related to prematurity or other causes can persist beyond infancy, keeping these children at risk during the RSV season. Requiring recent medical therapy ensures the child is truly at ongoing risk, not just a remote history.

The other options don’t fit as well because they either omit the timing requirement (the need for medical therapy within the last 6 months) or limit eligibility to age ranges or conditions that don’t align with the standard high-risk criteria during RSV season. For example, a preterm status without the timing of recent therapy, or a congenital heart disease criterion without specifying the recent need for therapy, would not capture the same precise high-risk group defined for prophylaxis during RSV season.

Thus, the criterion that best matches established RSV prophylaxis guidelines is infants and children under 24 months with chronic lung disease requiring medical therapy within 6 months prior to the RSV season.