Soldiers sent to Iraq were not made ill by the multiple vaccinations some received before their deployment, according to a study published today.
Being given too many jabs at once has been suggested as a possible cause of Gulf war syndrome and the illness some military personnel have reported after the 2003 invasion of Iraq.
But researchers from the King's centre for military health research, at King's College in London, say that in the 2003 conflict at least, the vaccinations were not to blame. Their study suggests that military personnel ascribing illness to the multiple vaccinations do not necessarily remember correctly how many jabs they were given.
"We found recall of vaccinations to be very poor," said Dominic Murphy, lead author of the study, published online today by the British Medical Journal. "People had difficulty remembering the total number of vaccinations they had. Those who were more unwell seemed to recall receiving more vaccinations."
The research team randomly selected 4,882 military personnel, who had an average age of 32, and who had been to Iraq since 2003. Before they were deployed, servicemen and women were routinely given tetanus, typhoid and yellow fever vaccinations. Anthrax was offered to individuals, who had to sign a consent form before it was administered.
The researchers asked all the study participants what was the maximum number of vaccinations they received in one day in preparation for being sent to Iraq. They then tested the accuracy of the servicemen and women's memories by finding and examining the medical records of 10% of the group.
They found that those people who said they had suffered illness after their deployment in Iraq were more likely to say they had been given multiple vaccinations in a single day.
But the medical records told a different story. The researchers found those whose records show they had had several injections were no more likely to be ill than those who had just one.
"Multiple vaccinations given to personnel in the UK armed forces in preparation for deployment to Iraq are not associated with adverse health consequences when vaccinations are recorded objectively from medical records," they write. "Adverse health consequences associated with self-reported multiple vaccinations could be explained by recall bias."
They say, however, that it is difficult to know whether the same problems over recollecting the detail of vaccinations applied to the 1991 Gulf war. The Gulf war veterans reported more vaccinations than combatants in the 2003 invasion - some said six or more - and it has been suggested that combining pertussis (whooping cough) with anthrax vaccination, which did not happen in 2003, could have caused the symptoms.