Yellow Fever Update:
Recent news reports have raised concerns about yellow fever vaccine safety. It is important to understand the risks and benefits.
For decades, the yellow fever vaccine was considered to be extremely safe. More recently, however, we have become aware of a low rate of serious adverse effects occurring when older travellers are vaccinated for the first time. The two main types of adverse effects are called YEL-AVD and YEL-AND – the first involves damage to organs such as the liver, and the second damages the nervous system. Yellow fever vaccines contain live viruses that do not harm people with a normally functioning immune system but do seem to cause harm in a tiny proportion of people with an ageing immune system, as well as those with reduced immunity from other causes.
In one of the largest medical studies of yellow fever vaccine safety, the rate of YEL-AND in people aged 60-69 was 2.5 per 100,000 people vaccinated, and in over 70s was 1.6 per 100,000. For YEL-AND, the rates were zero and 4.0 per 100,000 respectively.
According to the US Centers for Disease Control, in the absence of a yellow fever outbreak, the “background” risk of yellow fever occurring in unvaccinated travellers on a 2-week trip to a zone where yellow fever is present is calculated to be:
- West Africa: 50 cases per 100,000, with 10 deaths per 100,000
- South America: 5 cases per 100,000, with 1 death per 100,000
Yellow fever vaccinating centres normally explain these risks to everyone they vaccinate, and in particular to travellers aged over 60. Vaccination for personal protection is recommended where benefit outweighs the risks, and a medical waiver is given when it is not safe for the vaccine to be used. Age alone is not a reason for issuing a waiver.
Other factors that complicate the picture include the following:
- There are active outbreaks of yellow fever in several parts of the world, notably at present in Brazil as well as in several African countries, so the risk to travellers is often much higher than that quoted above.
- Vaccination is the only way to prevent and control yellow fever and is often the only possible public health measure for entire populations.
- Many countries therefore rigorously enforce vaccine requirements as a condition of entry.
- Yellow fever vaccine shortages are common – there is currently a serious shortage in the USA, and the vaccine is not always available when needed.
- Awareness of vaccine risks has come with a stricter approach to recommending vaccine only when travellers are definitely going to be at risk; however, an unintended consequence of this has been to delay the opportunity to vaccinate travellers for the first time until they are older and at greater risk of adverse effects.
The World Health Organization now considers vaccine protection to be life-long, though border officials in several countries do not always recognise this. A small number of recent cases of yellow fever in Brazil among people who had been vaccinated previously has raised further doubt about this policy, and Brazil currently recommends revaccination every 10 years. Revaccination has not been linked to adverse effects.
There is currently extensive UK press coverage (that has also been picked up in the US) of YF vaccine adverse effects – one death occurred shortly after vaccination in a distinguished cancer researcher, and a psychotic reaction in a former BBC journalist vaccinated in Greece. Both cases were attributed to the vaccine because of the timing. Further clinical details are not available, so we can’t yet be certain of a direct link, but this news will undoubtedly have a considerable impact on public perception of the vaccine.
Written by: Richard Dawood, Medical Director and specialist in travel medicine
Book your yellow fever vaccination today.
- Cancer pioneer Martin Gore’s sudden death from routine jab – Source: The Times
- I had a yellow fever jab, then the voices told me: ‘Kill! Kill! Kill!” – Source: The Times
UPDATED RECOMMENDATIONS FOR Yellow Fever VACCINATION: Nigeria
The World Health Organization recently updated the yellow fever recommendations and requirements for residents and travellers to Nigeria.
As of 1 July 2019, the yellow fever certificate requirement for travellers to Nigeria changed. All travellers aged 9 months or over are now required to travel with a yellow fever vaccination certificate along with a valid visa. Failure to provide a valid certificate where required could deny entry to that country, or result in quarantine.
Previously a certificate was only required for those arriving from risk areas countries. However, an on-going outbreak of yellow fever, which started in September 2017, is continuing therefore a revised classification has been made. Between January and April 2019, a total of 930 suspected cases were reported in 447 Local Government Areas.
Advice for travellers
The Fleet Street Clinic would like to remind all travellers from the United Kingdom that there is a risk of yellow fever transmission throughout Nigeria.
We are a Certified Yellow Fever Centre with availability throughout the week and are usually able to accommodate same day appointments requests.
What is Yellow Fever?
Yellow Fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes and has the potential to spread rapidly and cause serious public health impact. There is no specific treatment, although the disease is preventable using a single dose of yellow fever vaccine, which provides immunity for life.
For more information about Yellow Fever & the Vaccine.
Anyone travelling to Nigeria should book a Pre-Travel Consultation. One of our specialist Travel Nurses will access if a Yellow Fever vaccine is suitable for you.
World Health Organization
Dr Richard Dawood, our Medical Director and Travel Medicine specialist answers frequently asked questions about Yellow Fever and the Yellow Fever vaccine in our new video.