Face-to-face consultations temporarily suspended:

Following the calls of the First Minister and Chief Medical Officer (24th March), TrExMed Travel Clinic has now suspended all non-essential, face-to-face consultations and vaccinations until further notice.

This is to help slow down the spread of the Coronavirus (SARS-CoV-2) among the general population, and so ease the peak burden upon the NHS of COVID-19 disease.

We are, however, still more than happy to help answer any queries regarding travel health risks and vaccinations by email (preferred method) or by telephone.

Take care and keep well, Nicky & Jim

Yellow Fever

Yellow Fever vaccine is just one of the travel vaccinations we offer at the Travel Clinic.  Yellow Fever vaccine can only be administered by a registered Yellow Fever Vaccination Centre.

Yellow Fever is a potentially very serious viral infection, which can be transmitted to humans in some parts of the world by day-biting mosquitoes, typically Aedes (also known as Stegomyia) species.

The natural reservoir is monkeys and other primates (including humans) in Africa and South America.  Monkey-to-human transmission (via mosquitoes) leads to sporadic cases of Yellow Fever in people living in or visiting forested areas.  This is sometimes known as 'jungle Yellow Fever' and was, until recently, the most common route of transmission in South America.

Infected people, leaving the bush to more populated areas can then also cause onward human-human transmission (again via mosquitoes) and more widespread, cyclical outbreaks from time to time - so called: 'urban Yellow Fever'.  This is the more common mode of transmission in Africa.

From 2016-18, there was an unusually large epidemic of Yellow Fever in South America, with spread to monkeys and humans in areas not previously affected or not affected for many decades, particularly Minas Gerais, Rio de Janeiro and São Paulo States of Brazil. There has also been a number of (mainly urban) outbreaks in Central Africa (Angola, DRC, Congo and Uganda) around the same time. The maps and categories of at-risk areas for Yellow Fever transmission have therefore recently been adjusted to take into account the shifting epidemiology.

How serious Is Yellow Fever?

Although most infections go unnoticed, in others there is a sudden-onset high fever, headache, back and muscle ache, nausea and vomiting.

In 15% of cases, the fever progresses to a second, more serious phase with liver failure and jaundice (hence 'Yellow'), abdominal pain and haemorrhagic symptoms such as bleeding from eyes, nose, bladder and gut.  Half of these cases die within 10-14 days.

However, the risk of harm from the disease needs to be carefully balanced against the risk of side effects from the vaccine (see below).

Prevention

  • There is a very effective vaccine available, providing long-term protection. This is given both a) to prevent the international spread of disease by protecting countries from travellers who may be carrying the virus, and b) to protect the individual traveller who may be exposed to infection.
  • Avoid getting bitten! Use Insect repellents such as Mosiguard Natural® or DEET on exposed skin and cover up in at-risk areas. Even if you are protected against Yellow Fever by the vaccination, you may still be at risk from dengue, chikungunya (both spread by the same mosquitoes) and other diseases borne by biting beasties, for which there are no vaccinations available yet.
  • Travelling at altitude, e.g. itineraries all above 2,000 metres in Ethiopia, is relatively safe as few mosquito species can survive at that height.

Mandatory Yellow Fever vaccination

For some regions, a valid 'international certificate of vaccination or prophylaxis' (or an exemption certificate) is required by immigration control to enter the country.  The vaccination certificate only becomes valid ten days after receiving the vaccine, but is now valid for life.

For details of which countries require a certificate, please visit www.fitfortravel.scot.nhs.uk

Please note that just because a country does not require a certificate to enter the country, this does not mean that there is no risk of infection in that country!

Yellow Fever vaccination: is it safe?

  • No vaccination is 100% free of side-effects.
  • Common side effects include a viral or flu-like feeling, 5-10 days after the vaccination, as YF is a live vaccine.
  • Very rarely, encephalitis (YF vaccine-associated neurotropic disease) or severe hepatitis (YF vaccine-associated viscerotropic disease) may occur, which can be fatal, particularly in the latter.  The risks of these, much more serious side-effects are higher in elderly travellers who have not had the vaccine before.  The risk of YEL-AND is 8 per million, rising to 22 per million if given for the first time over 60 years old.  The risk of YEL-AVD is 3 per million under the age of 60, rising to 10 per million between 60-70 years old and 23 per million over 70.  

Contraindications

  • Contraindications include: age, pregnancy, immunodeficiency from medication or disease, severe egg allergy and previous hypersensitivity reaction to the Yellow Fever vaccine.
  • Yellow Fever vaccine is not recommended for children under 9 months of age, (but may, depending on risk, be prescribed as early as six months of age if need be.)
  • The risks of serious side-effects, including death, are relatively greater in the elderly (see above).

If, after careful assessment, the risks to health are considered to outweigh the benefits, an exemption certificate for Immigration purposes may be issued by a registered Yellow Fever Vaccination Centre, such as the TrExMed Travel Clinic.

Yellow Fever Consultation

Some travellers are surprised to hear that they still need a 'single item appointment' before receiving a Yellow Fever vaccination, even if they have been told they need to have it by their own GP.  This is because, as responsible practitioners, we have to assess:

  1. What your actual risks are of acquiring Yellow Fever infection on your particular itinerary (i.e. do you really need it, to protect your health?)
  2. Is it safe to give you the vaccination, considering your past/current medical history and age (i.e. would the risks of serious side effects from the vaccination actually outweigh any potential benefit?)
  3. Would another plan be more appropriate - e.g. delaying travel, or issuing a Yellow Fever exemption certificate?

© Jim Bond Jan 2020

Young woman with beautiful coloured dress in Dakar, Senegal: Urban Yellow Fever is an ongoing risk in West Africa

Kumasi market, Ghana: high risk for falciparum malaria and possible risk for urban Yellow Fever
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