Significant immunosuppression, such as from solid organ transplant, haematopoietic stem cell transplant, or primary immune deficiencies such as severe combined immunodeficiency (SCID)
Chronic lung disease requiring ongoing oxygen or respiratory support
Neurological conditions that impair respiratory function
Cystic fibrosis with severe lung disease or weight for length <10th percentile
Trisomy 21 or another genetic condition that increases the risk of severe RSV disease
