New guidelines regarding the use of palivizumab to reduce the risk of respiratory syncytial virus now further restrict which infants should receive the prophylaxis. The new guidelines, issued by the American Academy of Pediatrics, replace the previous ones from 2012.

Approximately 2.1 million children under age 5 develop an RSV infection requiring medical care each year, including about 58,000 who are hospitalized during their first few years of life. The highest-risk age for RSV hospitalization is 2 months.

However, palivizumab (Synagis), an immunoglobulin monoclonal antibody, can reduce the risk of hospitalization for RSV. The standard prophylactic dose is 15 mg/kg every 30 days during RSV season, for up to five doses. Palivizumab does not interfere with immunizations and can be administered at the same time as vaccines.

The main changes in the updated guidelines reduce the number of infants who will qualify for the prophylaxis, according to the policy statement published online by the AAP Committee on Infectious Diseases, chaired by Red Book Associate Editor Michael T. Brady, and the AAP Bronchiolitis Guidelines Committee (Pediatrics 2014 July 28 [doi: 10.1542/peds.2014-1665]).

Whereas all otherwise healthy preterm infants born at less than 32 weeks were previously recommended to receive palivizumab, now only those born at less than 29 weeks are recommended to receive it.

However, recommendations for palivizumab remain in place for preterm infants younger than 32 weeks’ gestational age who have chronic lung disease of prematurity and needed more than 21% oxygen for at least the first 28 days after birth. In addition, as in the previous guidelines, these children should receive palivizumab only during their first year of life unless, in their second year, they still need medical support in the 6 months before RSV season starts. Medical support includes supplemental oxygen, chronic corticosteroid therapy, or diuretic therapy.

Infants less than 12 months old with hemodynamically significant congenital heart disease should still receive palivizumab, particularly if they have moderate to severe pulmonary hypertension or if they have acyanotic heart disease and either take medication to control congestive heart failure or else will need heart surgery. However, children older than 12 months are no longer recommended to receive the prophylaxis (previous guidelines went up to 24 months), nor are those who have hemodynamically insignificant heart disease, who have surgically corrected lesions, who do not need drugs for congestive heart failure, or who have mild cardiomyopathy but do not need therapy.

Unless they have another qualifying condition, children with Down syndrome or cystic fibrosis also are not recommended to receive palivizumab, even though some evidence shows that these children may be at higher risk for RSV. The 2012 guidelines did not have a recommendation for or against palivizumab for children with cystic fibrosis, but data from studies since then bolster the case to exclude these children from receiving the prophylaxis because of limited evidence of clinical benefit.

Further, a group no longer recommended to receive palivizumab are those born between 32 and 35 weeks who were born within 3 months of RSV season and either attended childcare or had a sibling under age 5.

As in 2012, palivizumab "may be considered" for two groups of children: those less than 24 months old undergoing chemotherapy or otherwise severely immunocompromised, and those with pulmonary abnormalities or neuromuscular disorders that prevent them from coughing sufficiently to clear upper-airway secretions.

Another change in the updated recommendations is to cease prophylactic doses of palivizumab if a child is hospitalized with a breakthrough RSV infection. Previous guidelines advised that doses continue through the maximum recommended amount, but this has been removed in the new statement because fewer than 0.5% of infants are rehospitalized with RSV in the same season. Palivizumab is still not recommended for prevention of health care–associated RSV or to treat RSV.

The updated guidelines are based on new data, including revised (lower) estimates of RSV mortality in hospitalized children, information on RSV seasonality, declining bronchiolitis hospitalizations, data on palivizumab benefits for children with cystic fibrosis or Down syndrome, and "reports describing palivizumab-resistant RSV isolates from hospitalized patients who receive prophylaxis." These data are summarized in the technical report by the AAP Committee on Infectious Diseases (Pediatrics 2014 July 28 [doi: 10.1542/peds.2014-1666]).

Palivizumab was licensed by the Food and Drug Administration in June 1998, largely based on the results of a randomized controlled trial in 1996-1997 involving 1,501 preterm infants and young children (some with chronic lung disease of prematurity). A second randomized controlled trial was performed in 1998-2002 involving 1,287 children with hemodynamically significant congenital heart disease.