You have only to read through our weekly travel health alerts to appreciate that travel medicine is an ever-changing field and, while new vaccines, preventive medications and treatments are not developed every day, new diseases emerge, and previously common ones re-emerge, on a regular basis.
Regulations surrounding health requirements for travellers arriving in any country are largely set by that country but, in this age of mass rapid transport, all nations have an interest in stopping or limiting the spread of infectious disease threats. For that purpose the International Health Regulations (IHR)1,which were established (and are regularly monitored) by the Member states of the World Health Organisation (WHO) at the World Health Assembly meetings, aim ‘to help the international community prevent and respond to acute public health risks that have the potential to cross borders and threaten people worldwide2.’ The IHR are updated when new information is received as in the case of disease outbreaks or changes in vaccine recommendations. Yellow fever3 is currently the only disease under the IHR ‘for which proof of vaccination may be required for travellers as a condition of entry to a State Party’.
In an Amendment to International Health Regulations (2005), Annex 7 (yellow fever)4, the duration of protection offered to people with normally functioning immune systems from the yellow fever vaccine has been extended to the life of the person vaccinated. This follows a recommendation made by the WHO’s Strategic Advisory Group of Experts on Immunisation (SAGE) back in 2013 ‘that a single dose of vaccination is sufficient to confer life-long immunity against yellow fever disease5’. (If the yellow fever vaccine cannot be administered due to medical contraindications, a waiver letter can be provided by a licensed medical practitioner. Travellers should check with the embassies or consulates of all countries on a planned itinerary to ensure this document will be accepted at border controls.)
The Australian government’s implementation of the Annex 7 amendments took effect on June 16th, 2016 and advice provided on the Department of Health website was updated to, ‘From 16 June 2016, international yellow fever vaccination certificates presented at Australia’s border will be accepted even if the vaccination was given more than ten years ago6.’
The thing is, all situations are not necessarily clear-cut … While a traveller may not need the yellow fever vaccination to enter a country (sometimes even when the disease is present there), proof of vaccination may be required for the next destination on their itinerary, or the one after. We have to consider the timing of the itinerary as well as the areas and countries visited.
And now to a matter that needs to be discussed when planning travel that includes yellow fever risk regions: A recent article on arrivals into Tanzania published in the Journal of Travel Medicine confirms information we have from some of our clinics. Immigration authorities in some countries will randomly request to check yellow fever vaccination documents (even from travellers who have not arrived from a yellow fever-affected area or only transited one briefly - <12 hours). In the case of arrival from a yellow fever risk area, if a valid certificate or waiver letter cannot be produced, an on-the-spot fine may be issued or the vaccine is administered there and then, otherwise entry is prohibited. The journal article also details how the departure point, arrival port and mode of transport into a country sometimes determined whether vaccination certificate checks were more likely to be carried out.
Further, while Australian authorities will accept yellow fever vaccination certificates issued over 10 years previously, that is not necessarily the case in all countries; the onus is on each traveller to check that their certificate or waiver letter will be accepted by border officials on arrival. In one instance that we have been made aware of, travellers planning a trip to Ghana had to return to a clinic in Adelaide to be revaccinated against yellow fever despite having a valid vaccination certificate as far as Australian laws are concerned i.e. issued more than 10 years ago but current under our new regulations. The travellers were advised by the Ghanaian authorities that if they did not have a new, current vaccination certificate they would be vaccinated at the airport on arrival and would not be allowed to leave their accommodation for 7 days.
Yellow Fever
The disease:
Yellow fever is a viral haemorrhagic infection that is reported in tropical areas of Africa and Central/South America. Transmission occurs in jungle (sylvan) areas where mosquitoes transmit the disease from monkey hosts to other primates or humans AND in urban areas where the Aedes mosquito spreads the infection among the human population.
Risk to travellers:
Yellow fever occurs only rarely in travellers (because the vast majority travelling to yellow fever risk areas have been vaccinated), however it does present a risk, particularly if the conditions are right: season, duration of travel to endemic area and sub-optimal insect bite avoidance measures. If travelling to a country where yellow fever is present, travellers should take precautions against insect bites and discuss the appropriateness of yellow fever vaccination at a yellow fever accredited medical centre.
Signs and Symptoms:
The incubation period of yellow fever ranges from three to six days and leads to the acute phase characterised by fever, muscle pains, headache, shivers, nausea and vomiting. Treatment is symptomatic. Most infected individuals will improve, but around 15 percent will experience a temporary remission (saddle-back fever) then deteriorate, passing into the toxic phase of the illness. Jaundice and bleeding complications such as vomiting blood, bleeding gums and blood-stained urine lead to shock and multiple organ failure. Death rates in this phase range from 20 to 50 percent and mostly occur 7–10 days after onset.
Prevention:
Live attenuated viral vaccine (Stamaril)
Standard schedule
• Single dose protects for life (an International Certificate of Vaccination or Prophylaxis is required to confirm vaccination – this becomes valid 10 days after vaccine administration).
• Suitable for ages 9 months and over.
Discuss yellow fever vaccine administration contraindications and precautions with your yellow fever licenced prescribing practitioner.
Contact Travelvax Australia’s travel health advisory service (1300 360 164) for country-specific information and advice, including possible immunisations, for your next overseas travel. You can also make an appointment to have your vaccinations completed in a consultation with a team of medical professionals experienced in travel medicine.
1. http://www.who.int/topics/international_health_regulations/en/
2. http://apps.who.int/iris/bitstream/10665/246107/1/9789241580496-eng.pdf?ua=1
3. https://www.travelvax.com.au/holiday-traveller/yellow-fever
4. http://www.who.int/ith/annex7-ihr.pdf
5. http://www.who.int/mediacentre/news/releases/2013/yellow_fever_20130517/en/
6. http://www.health.gov.au/internet/main/publishing.nsf/content/health-pubhlth-strateg-communic-factsheets-yellow.htm
