Travel health update

This month’s update focuses solely on an important update to the recommendations for yellow fever vaccine, which aim to prevent rare but potentially fatal adverse events in certain patient groups

Having just had a birthday that entitles me to a free bus pass, I’m reminded that I now fall into the category of a senior traveller – which outrages me somewhat as, in my head, I’m only 25! We see an increasing number of ‘baby boomers’ who have more time and are likely to have more disposable income to enable them to take all sorts of exotic trips, Christmastime included! However, there are some issues to be very aware of as a result of updated guidance on yellow fever.

IMPORTANT YELLOW FEVER VACCINE UPDATE

The Report of the Commission on Human Medicine’s Expert Working Group on benefit-risk and risk minimisation measures of the yellow fever vaccine was published towards the end of November.¹ This was the culmination of work over several months and included contributors from Public Health England, NaTHNaC, Health Protection Scotland and the Medicines and Healthcare products Regulatory Agency (MHRA). They have also published a letter which explains the issues and summarised specific recommendations,² which is essential reading.

The recommendations strengthen measures to minimise the potential risk of rare but serious and fatal adverse events associated with yellow fever vaccination in those with weakened immune systems, and in particular those aged 60 years or older and anyone who has had their thymus removed. There are two risks unique to yellow fever vaccine, viscerotropic disease (YEL-AVD) and neurotropic disease (YEL-AND), which both resemble yellow fever infection. These are very rare but can be fatal. These side effects are more likely to occur in certain groups, particularly people with a weakened immune system and people aged 60 years or older. The risks of YEL-AND and YEL-AVD are estimated to be up to 1 per 100,000 in those receiving vaccine for the first time, although this risk may be four or more times greater in those aged 60 years or older.

The review came about following notification to the MHRA of two fatal adverse reactions to yellow fever vaccine. In one case, the vaccine was given to a person with a history of thymectomy following a thymoma (a contraindication stated in the Summary of Product Characteristics [SmPC]). In another case, the vaccine was given to a 67-year-old with no other known risk factors. Both patients died shortly after vaccination due to suspected YEL-AVD.

The full report recommends that the SmPC should be updated to include thymectomy for any reason as a risk factor, and that the Green Book should also be updated to reflect this. The report goes on to state: ‘the Green Book should also specify that those who underwent surgery for congenital heart disease should be considered at high risk of developing complications following vaccination because for this group, thymectomy is routinely performed during cardiothoracic surgery to enable better access to the heart and great vessels. Therefore, a precautionary approach should be used unless there is evidence that their thymus was not removed.’

At the time of writing, an update to the Green Book is awaited, amongst other guidance. NaTHNac has strengthened its vaccine recommendations on many of its Country information pages for travellers aged 60 years and older visiting countries with a low potential for exposure to yellow fever – see https://travelhealthpro.org.uk/news/470/yellow-fever-vaccination-recommendations-persons-aged-60-years-or-older. So for example, for Kenya it now says that for the parts of the country with low potential for exposure to yellow fever (and names the areas), people aged 60 years or older should not be given the vaccine for these areas due to a higher risk of life-threatening side effects. Note the letter also specifies, for example, that only healthcare professionals specifically trained in benefit-risk evaluation of yellow fever vaccine should administer the vaccine – make sure you read the full guidance in this letter. I’ve written a blog on the whole topic with more background at http://janechiodini.blogspot.com/2019/11/important-yellow-fever-update.html

SEASON’S GREETINGS

Well, I’m staying put in London for the festive season, but wherever you are I hope you have a good break and I wish you a Happy New Year, good health and success through 2020.

References

1. Commission on Human Medicines. Report of the Commission on Human Medicine’s Expert Working Group on benefit-risk and risk minimisation measures of the yellow fever vaccine; 21 November 2019. https://www.gov.uk/government/publications/report-of-the-commission-on-human-medicines-expert-working-group-on-benefit-risk-and-risk-minimisation-measures-of-the-yellow-fever-vaccine

2. Raine J, et al. Yellow fever vaccine: stronger precautions in people with weakened immunity and those aged 60 years or older; 21 November 2019. https://travelhealthpro.org.uk/media_lib/mlib-uploads/full/2019-11-21-yellow-fever-vaccine-precautions-letter.pdf