According to a study published on the British Medical Journal website, multiple vaccinations have not sickened British troops deployed to Iraq.

Dominic Murphy and colleagues studied randomly selected and assessed the medical health records of 5000 military personnel (deployed to Iraq since 2003) who were administered tetanus, typhoid and yellow fever. It was concluded that veterans who reported illness were more likely to have remembered receiving multiple vaccinations even when their medical records indicated otherwise.

In view of these findings and the impact of "recall bias" the researchers say "there is no evidence that receiving multiple vaccinations has resulted in adverse health for UK service personnel deployed to Iraq since 2003."