ON OCTOBER 20, 1997, the Food and Drug Administration licensed a new rabies vaccine for both pre-exposure and postexposure prophylactic use in humans. This purified chick embryo cell culture (PCEC) vaccine (RabAvert®)* is manufactured by Chiron Behring GmbH and Company. The addition of PCEC to the current products available for pre-exposure and postexposure prophylactic use in humans allows for greater flexibility in treatment choices for the vaccination candidate who develops a sensitivity to one of the other available vaccines. Although derived from chick embryo cells, antibodies to chick cell proteins were not detected in recipients of the vaccine.1
Before introduction of the PCEC vaccine, two other products were licensed for use as rabies vaccines in the United States: human diploid cell vaccine (HDCV) and rabies vaccine adsorbed (RVA). HDCV uses the Pitman Moore strain of fixed rabies virus propagated in infected human diploid cells, and RVA uses a Kissling strain of rabies virus adapted to a diploid cell line of fetal rhesus lung.2,3
The PCEC vaccine has been shown to be safe and immunogenic when the current Advisory Committee on Immunization Practices guidelines are employed.4,5 These guidelines are as follows: pre-exposure vaccination for persons not previously vaccinated consists of three 1.0-mL doses delivered intramuscularly in the deltoid region for adults and in the anterolateral zone of the thigh for young children on days 0, 7, and 21 or 28 (day 0 indicates the start of treatment); postexposure vaccination with PCEC in persons not previously vaccinated consists of five 1.0-mL doses delivered intramuscularly in the same regions as for pre-exposure vaccination on days 0, 3, 7, 14, and 28, plus one dose of human rabies immune globulin (HRIG) at 20 IU per kg of body weight on day 0. As much as possible of the full dose of HRIG should be thoroughly infiltrated into and around the wound(s). Any remaining volume should be administered intramuscularly at a site distant from the vaccine inoculation. Postexposure prophylaxis for those persons who have been previously vaccinated should consist of two 1.0-mL doses delivered intramuscularly, in the same regions as previously stated for adults and children, on days 0 and 3. HRIG should not be administered to previously vaccinated persons.4
On the basis of information provided by the manufacturer6 RabAvert® is a sterile freeze-dried vaccine obtained by growing the fixed-virus strain Flury low egg passage (LEP) in primary cultures of chicken fibroblasts. The tissue culture fluid is harvested and filtered to remove cell debris. The virus is inactivated with b-propiolactone, then further purified and concentrated by zonal centrifugation. The vaccine is lyophilized after addition of a stabilizer solution in 1.0-mL amounts, which supplies at least 2.5 IU of rabies antigen. No preservative is contained in the vaccine, and the vaccine should be used immediately after reconstitution. The vaccine is designed for intramuscular use only.
The manufacturer also reported the occurrence of a substantial amnestic antibody response with no reports of IgE-mediated hypersensitivity when PCEC was used as a booster, regardless of the vaccine used for primary vaccination. As with the other available products (HDCV and RVA), local reactions such as swelling, induration, and reddening have been associated with administration of PCEC. Because the product contains trace amounts of animal by-products, antibiotics, and human serum albumin, systemic allergic reactions are possible and have been reported.
Viral and Rickettsial Zoonoses Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC.
Availability of New Rabies Vaccine for Human Use. JAMA. 1998;279(6):422-423. doi:10.1001/jama.279.6.422-JWR0211-2-1