Chiron Corporation is recalling and withdrawing its measles, mumps and rubella (MMR) vaccine, Morupar. Chiron supplied approximately 5 million doses of Morupar vaccine in 2005, providing most of its production to a limited number of developing countries, largely via the United Nations Children's Fund (UNICEF) and the Pan American Health Organization (PAHO), and approximately 450,000 doses to Italy.

The results of routine pharmacovigilance surveillance in Italy suggest that Morupar vaccine may be associated with a higher reported rate of adverse events following immunization than other MMR vaccine products. While recent and historical surveillance data indicate that adverse events remain rare, Chiron is recalling and withdrawing the vaccine as a precautionary measure. Pharmacovigilance results suggest that these adverse events occurred post-immunization and do not indicate any long-term risk for patients who have previously received the vaccine. The adverse events on which the recall and withdrawal are based are within a range of those commonly associated with vaccines, such as fever, allergic reactions and swelling of the glands, stated a company release.

Chiron has been in communication with the relevant health authorities and informed them of its actions in order to enable them to find replacement supplies of MMR vaccine. Chiron will work closely with the World Health Organization (WHO) to assist it in conducting a thorough risk-benefit analysis of Morupar vaccine to determine whether it is appropriate for a limited quantity of the existing inventory to remain available for current public health programs such as those conducted by UNICEF and PAHO.

In 2005, Chiron's sales of Morupar vaccine totalled approximately $10 million. Chiron has written-off approximately $6.0 million of Morupar inventory in 2005 as a result of the withdrawal and has recorded approximately $1.7 million of product returns reserves in 2005 in connection with expected returns of 2005 product sales from the recall. The recall and withdrawal of Morupar, which Chiron produces in Italy, does not affect any of Chiron's other vaccines, added the release.