On Oct. 20, 1997, the Food and Drug Administration (FDA) licensed a new rabies vaccine for both pre-exposure and postexposure prophylactic use in humans. This purified chick embryo cell culture (PCEC) vaccine (RabAvertTM) is manufactured by Chiron Behring.

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.

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.

The PCEC vaccine has been shown to be safe and immunogenic when the current Advisory Committee on Immunization Practices guidelines are employed. 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.