Children who receive multiple doses of the Haemophilus influenzae b (Hib) vaccine are at increased risk of developing type I juvenile-onset diabetes, according to new American research.

When researchers in Baltimore compared children who had received four, one and no doses of the vaccine, the cumulative incidence of diabetes per 100,000 in the three groups was 261, 237 and 207 at age 7 and 398, 376 and 340 at age 10, respectively. This works out to be that the greatest increased risk is among children who receive the full quotient of the vaccine.

The incidence of diabetes among US children aged five to 10 had been stable in the 10 years prior the introduction of the vaccine.

The increased risk of diabetes - which is just one of the potential adverse effects of the Hib jab - certainly exceeds the benefits of the vaccine, say the Baltimore research team. The Hib vaccine has been estimated to prevent approximately seven deaths, and between seven and 26 cases of severe disability per 100,000 children who have been immunised (BMJ, 1999; 319: 1133).

* In another study, scientists have found that the routine vaccination of newborns with the hepatitis B vaccine increases the risk of fever (Arch Dis Child, Fetal and Neonatal Edition, 1999; 81: F206-7). A before-and-after study showed a link between the launch of the vaccination programme in Israel and the number of babies with unexplained fever in the first three days of life. As yet, the scientists do not know what significance this finding has for the short- or long-term health of the infants.