America's top health officials have delayed the introduction of the inactivated poliovirus vaccine (IPV) even though they know that the live version is causing up to 10 cases of paralytic polio every year.

They were expected to back the decision of two groups that deal with vaccination policy, who had both recommended the ending of the live vaccine.

The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention was worried about implementing the new programme, but has not ruled it out forever.

The two groups that wanted to stop administering the live vaccine had recommended that IPV should be given for the first two or three doses, with a live oral vaccine then given only at 18 months, and once more when the child was aged between four and six (JAMA, July 5, 1995).

A new, and supposedly safer, strain of the pertussis (whooping cough) vaccine may be available in the US within six months. It is an acellular vaccine usually the whole-cell version is given and is supposedly safe to use on babies aged between two, four and six months. Up to now, acellular vaccines have been approved for use only as booster shots on older children. Babies are more susceptible to the fever, swelling and other side effects of the whole-cell vaccination.

Doctors are hoping that the new vaccine will eliminate parents' worries about the whooping cough jab. Although there were only 4,600 cases of whooping cough in 1994 in the US, health authorities are trying to eliminate the disease entirely.

Four acellular vaccines are being tested in Europe; three of them showed fewer side effects than the whole-cell variety.