The MMR (measles, mumps, rubella) vaccination may cause autism and Crohn's disease, five studies to be published later this year will reveal.
The UK government is launching an immediate inquiry into the safety of the vaccine, which is currently given to nine out of 10 children. Eight million British schoolchildren were given the vaccine three years ago as a safeguard against a supposed measles epidemic.
The author of one of the five studies is Dr Andrew Wakefield of the Royal Free Hospital in North London, who believes the interaction of the various components of the vaccine could be responsible for causing autism and Crohn's.
He said the results, based on research from the UK and other countries, "clearly confirm our suspicions and take them further", he told the medical magazine Pulse.
Dr Wakefield said the number of children developing Crohn's disease had escalated dramatically since the 1960s when the measles vaccination was introduced in the UK. Doctors are sending him up to six cases a week of children with Crohn's or with autistic disturbances believed to be brought on by the MMR vaccine.
He suspects the vaccination could also be responsible for inflammatory bowel disease, although there is not enough evidence yet to confirm this.
Chickenpox and measles are more likely to be serious illnesses in adults than in children. A recent outbreak of measles in Greece resulted in 79 adults being admitted to hospital. Seventy six of those who contracted measles had been immunized with monovalent vaccine, which had been the standard preventative before the new generation of the MMR vaccine was introduced (BMJ 1997; 315: 262).
The Hib vaccine protects against Haemophilus influenzae type b, but doctors forget there are two other types of meningitis type d and f which are equally deadly.
The vaccines may open the door for other serotypes to emerge as new threats, two doctors at the Malmo University Hospital in Sweden have warned (Lancet, 1997; 350: 222).