Yellow fever vaccine advice changed
For many years, it has been thought that travellers and expatriates needed to obtain booster jabs in order to ensure their immunity against yellow fever, but new advice from the Strategic Advisory Group of Experts on Immunisation (SAGE) claims that one single dose of the vaccine will be enough for lifetime protection. The SAGE panel said its findings and recommendation were based on a review of the history of yellow fever immunisation over the past 80 years. In the aforementioned time period, around 600 million doses of the vaccine have been administered, and there have been just 12 documented cases of the vaccine failing to protect someone from infection. Each of these failures occurred within five years of the dose being given, which, said the panel, suggests that immunity does not decrease with time. Reasons offered for such failures included reduced immunity in the person receiving the vaccine, or a break in the chain of delivery (for example, not being kept at the right temperature) that would have rendered the vaccine ineffective.
Dr Helen Rees, chair of SAGE, confirmed the findings: “Looking at really very good evidence, it was quite clear to SAGE that a single dose of yellow fever vaccine is effective. This is extremely important for countries where yellow fever is endemic: it will allow them to reconsider their vaccine scheduling. It is also important for travellers.” The recommendation by SAGE, while it may take some time for individual countries to adopt, could mean that travellers who can prove they have had at least one documented dose of the vaccine will no longer require a booster shot for travel to countries where yellow fever is an issue.
Some travellers, for example those who are pregnant, are not required to have a vaccine anyway, due to the increased risk of an adverse reaction. In such cases, travellers exempt from the requirement will need to carry with them a letter supplied by a licensed yellow fever clinic that explains why they do not need a vaccine.