The American Academy of Pediatrics has officially endorsed a 2010 recommendation by the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices that reduces by one the number of vaccine doses required for postexposure rabies prophylaxis.
The recommendation calls for a reduction in the number of postexposure doses of human diploid cell vaccine (HDCV) or purified chick embryo cell vaccine (PCECV) from five to four doses, with the first dose of 1 mL to be given intramuscularly as soon as possible after exposure (day 0) and subsequent doses to be given on days 3, 7, and 14 after the first dose except in people with immune suppression, who should continue to receive the five-dose regimen with the fifth dose given on day 28.
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Despite the rarity of cases of human rabies infection, potential exposure due to animal bites is common.
The recommendation is the result of a review beginning in 2007 during a time when human rabies vaccine was in limited supply. The Advisory Committee on Immunization Practices (ACIP) formed a work group to review rabies vaccine options, and found that four doses were adequate for inducing rabies-neutralizing antibody, according to an AAP Policy Statement published March 28 in Pediatrics, which announces the AAP’s endorsement of the recommendation (Pediatrics 2011 March 28 [doi: 10.1542/peds.2011-0095]).
A detailed review by the ACIP rabies work group of the evidence in support of the reduced dosing schedule showed that in all of approximately 1,000 patients, an adequate immune response to vaccination was achieved by day 14 (when the fourth dose of cell-derived rabies vaccine was given). In addition, observational studies of people with likely rabies exposure showed that no cases of rabies have been attributed to the lack of a fifth dose.
Furthermore, animal models demonstrated that the number of vaccine doses did not contribute to significant differences in survival rate, and, theoretically, a reduced dosing schedule would result in similar or reduced rates of adverse reactions, which already are uncommon in children even when five doses are given.
Finally, the ACIP recommendation, which was published in 2010 (MMWR 2010;59:1-9), showed that reducing the dosing schedule to four doses would result in an estimated $16.6 million cost savings to the U.S. health care system.
Approximately 20,000-30,000 people receive rabies postexposure prophylaxis (PEP) in the United States each year, and one to three cases of human rabies occur each year, according to the AAP Policy Statement. Since the 1970s, with the introduction of modern cell-derived vaccines, no PEP failures have occurred.
Effective PEP has been attributed to prompt washing of the wound with copious amounts of soap and water, infiltration of human rabies immunoglobulin (HRIG) into and around the wound, and an appropriate dose schedule of intramuscular vaccine, which is now considered to be four doses in most patients, according to the Policy Statement. All other rabies PEP recommendations remain the same.
It is important that pediatricians be up to date on the new recommendations for rabies PEP, Dr. Mary Ann Jackson said in an interview.
"Despite the rarity of human rabies infection in the United States, questions for the pediatrician arising from potential animal exposures are surprisingly frequent, as animal bites and even bat exposures occur not uncommonly in the pediatric population," said Dr. Jackson, chief of the pediatric infectious diseases section at Children’s Mercy Hospitals & Clinics, Kansas City, Mo.
Pediatricians also need to know that the decision to embark on rabies PEP should be urgently but not emergently handled, she added, explaining that most exposures relate to domestic animal encounters (often strays) or incidents in which bats are found in the family home.
"Careful attention to information gathering related to the exposure is key (see our form at www.childrensmercy.org/rabiesform), and practitioners should utilize their health department and local infectious disease specialists for input in situations where PEP is considered," she said.
Dr. Jackson, who also is a professor of pediatrics at the University of Missouri–Kansas City, advised that in any instance where PEP is being considered, it is important to keep in mind that wound cleansing is essential and the child’s tetanus vaccine history should be confirmed, with vaccine provided in appropriate cases. Rabies immune globulin must be concurrently given in the wound site in addition to rabies vaccine in an alternative site in every case where PEP is being provided for the first time in an otherwise healthy child.
In the instance where a bat is discovered in the room of a sleeping child, the PEP decision is certainly straightforward if the animal is available for rabies testing, and results can be ascertained promptly. In an otherwise healthy domestic pet exposure, a 10-day observation period should be ensured, utilizing the assistance of the local animal control and public health officials and in low-risk situations, which may obviate the need for PEP, said Dr. Jackson, who is a member of the AAP Committee on Infectious Diseases that wrote the new AAP Policy Statement.