Sunday, 24 November 2019


Recent very important news has been published on yellow fever vaccine.

What is this news all about?
Back in April 2019, the Medicines and Healthcare Regulatory Agency (MHRA) published a Drug Safety Update 'Yellow fever vaccine (Stamaril) and fatal adverse reactions: extreme caution needed in people who may be immunosuppressed and those 60 years and older' found here.
It is strongly advised that you read this page in full, but some of the lead up to this was the fact that in recent months, they had been notified of 2 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 in the product information). 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 yellow fever vaccine-associated viscerotropic disease (YEL-AVD).

The guidance went on to explain they were in the process of reviewing the benefit-risk balance of yellow fever vaccine and measures to minimise risks in the light of these cases and the latest scientific data. The Commission on Human Medicines has convened an Expert Working Group, which will make recommendations. We will update guidance, as necessary.

A summary box was included: 

The Green Book at the time (updated in January 2019) provided clarity over individuals who had had an incidental removal of their thymus gland including the following details:

* To date there is no evidence of increased risk of yellow fever vaccine–associated serious adverse events in people who have undergone incidental surgical removal of their thymus (e.g. during cardiac surgery) or have had indirect radiation therapy in the distant past. People who had incidental removal of their thymus after the age of one year may therefore receive a yellow fever vaccine following a detailed risk assessment. A cautious approach is recommended for those who had incidental removal of their thymus before the age of one year. In these cases further advice should be sought.

In addition the NaTHNaC YF Factsheet on TravelHealthPro also provided the same message.  

So this is what I have been teaching this year.... 
even though the Green Book from January 2019 remains 
online at the current moment.  

So what has happened recently?
On 21st November NaTHNaC posted an update on TravelHealthPro entitled REVIEW OF SERIOUS ADVERSE EVENTS FOLLOWING YELLOW FEVER VACCINATION and on 22nd November TRAVAX posted a similar update entitled Strengthened Recommendations to Minimise Risk of Serious and Fatal Reactions to Yellow Fever Vaccination (password required for the latter link).  

'The Commission on Human Medicines (CHM) has recommended strengthened 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.

A joint letter from the MHRA, PHE, HPS and NaTHNaC gives further detail viewed HERE.

So although the Green Book chapter (35) on Yellow Fever is currently still up online as the January 2019 chapter, the GUIDANCE HAS CHANGED.  An update notice has been put on the landing page for this chapter which says 'The Commission on Human Measures (CHM) has recommended strengthened 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.

The Green Book chapter will be updated accordingly but for now, please see a joint letter issued by the MHRA, PHE, HPS and NaTHNaC which gives further detail'. See the image below as the page appears today.  

I have copied and pasted the information from the letter in the text below, but please make sure you click on the link and read it in full. 

Here is some of the important information
  • In people aged 60 years or older, due to a higher risk of life-threatening side effects, the vaccine should be given only when there is a significant and unavoidable risk of acquiring yellow fever infection, such as travel to an area where there is a current or periodic risk of yellow fever transmission - this would exclude travel to areas in which vaccination is ‘generally not recommended’ by WHO
  • Only healthcare professionals specifically trained in benefit-risk evaluation of yellow fever vaccine should administer the vaccine, following their individualised assessment of a person’s travel itinerary and suitability to receive the vaccine
  • Do not administer the vaccine to people:
    • who have had their thymus gland removed for any reason
    • who are taking biological drugs that are immunosuppressive or immunomodulating
    • who have a first-degree family history of YEL-AVD or YEL-AND following vaccination that was not related to a known medical risk factor (i.e. in case of an unidentified geneticpredisposition).
Thoroughly inform vaccinees about the early signs and symptoms of these side effects and to urgently seek medical attention if these side effects are suspected – this will support rapid identification and referral for treatment of YEL-AND and YEL-AVD. The manufacturer’s patient information leaflet should be given to everyone receiving a yellow fever vaccine as part of the travel consultation.

The letter goes on to let readers know that 
The above recommendations are in addition to the full list of contraindications and precautions described in the current Summary of Product Characteristics and patient information leaflet, which will be updated in due course. Standardised pre-vaccination screening checklists are also being produced, along with a patient group direction (PGD) template. A further communication will be issued when these are ready to ensure they are implemented in clinical practice. An article will be published in the MHRA’s Drug Safety Update ( with a detailed assessment report and more information about the risks and manifestation of YEL-AVD and YEL-AND.

The Report of the Commission on Human Medicine’s Expert Working Group on benefit-risk and risk minimisation measures of the yellow fever vaccine can be found HERE

This post and links to more resources will be updated as they become available.  

To download the current Yellow Fever Vaccine: Traveller Checklist from NaTHNaC - see here (published 10.07.19)
Latest News from NaTHNaC  - Yellow fever vaccination recommendations: persons aged 60 years or older posted 25.11.19 here  
NaTHNaC Yellow fever:  Information for Travellers Leaflet here

To view the CQC Mythbuster no. 91 on Patient Safety Alerts see here
To sign up for MHRA Patient Safety Alerts see here

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