Vaccine adverse events reported in New Zealand 1990-5

New Zealand monitors vaccine safety through vaccinator reports of adverse events following immunisation. The rate of reporting for the commonly used vaccines during 1990-5 are presented. During this time new vaccines were added to the immunisation schedule, enabling comparison of reporting rates.

The number of events were obtained from the CARM database and a rate calculated based on estimated vaccine use.

Injection site reaction with adult tetanus-diphtheria vaccine was most commonly reported (68/100,000); a rate five times higher than with tetanus vaccine. There were also more reported reactions from diphtheria-tetanus-pertussis-Haemophilus influenzae type b (DTPH) than DTP vaccine, with 'abnormal crying' the commonest reaction reported after 29/100,000 doses of DTPH and 3/100,000 doses of DTP. The next commonest reaction for DTPH was injection site reaction (25/100,000) which compares to 17/100,000 doses of DTP. For the other inactivated vaccines, more reports were made for fever following Hib (16/100,000), than for hepatitis B (2/100,000) or influenza (1/100,000). The most common reports following measles-mumps-rubella (MMR) vaccine were rash (17/100,000), fever (12/100,000), and injection site inflammation (5/100,000). There were very few reports following polio vaccine, with rash, fever and headache all reported at less than 1/100,000 doses.

Although only a proportion of events are reported, the picture presented here confirms the overall safety of vaccines and the value of the adverse event monitoring system. Monitoring vaccine adverse events is an essential part of the immunisation programme.