What is yellow fever?
Yellow fever is a serious and occasionally fatal disease caused by a virus. Yellow fever is transmitted to humans by infected mosquitoes, primarily the Aedes or Haemagogus mosquito. Areas with known risk of yellow fever include parts of Africa and parts of South America. Recently, an outbreak of yellow fever has evolved in parts of Brazil that were not previously deemed to be at risk of yellow fever transmission, including popular tourist destinations. The CDC has posted a Level 2 Travel Alert for Yellow Fever in Brazil. Since early 2018, a number of unvaccinated travelers to Brazil have acquired yellow fever disease and several have died.
However, the majority of people infected with yellow fever virus will either not have symptoms, or have mild symptoms and completely recover. Others may experience more severe symptoms, which are typically experienced between three and six days post infection. A few individuals may develop a more severe form of the disease, the symptoms of which include:
- High fever
- Yellow skin (jaundice)
- Organ failure
The overall mortality from the disease is 10-20%. Among those who develop the severe form of yellow fever, 30-60% will die. For an up to date list of additional areas where yellow-fever vaccination is recommended click here.
The most effective way to prevent yellow fever is to be vaccinated. Vaccinations are up to 99% effective in preventing a variety of tropical and infectious diseases. The World Health Organization recommends getting the yellow fever vaccine at least 10 days before you travel if you are going to a country that requires proof of yellow fever vaccination to enter (click here to view list). Vaccination is also recommended if you are travelling to a country with a risk of yellow fever (view risk map here), even if the country does not require proof of vaccination upon entry. Vaccination is recommended for healthy individuals older than nine months.
It is important to know that yellow fever vaccine is a live vaccine that is contraindicated in immunocompromised individuals and that it can rarely cause severe side effects, especially in the elderly. In some cases the risk of the vaccine outweighs the risk of infection and therefore a frank discussion with a travel medicine advisor will focus on prevention of insect bites and the documents needed to cross international borders where the vaccine is required.
Where can I obtain yellow fever vaccine?
There is currently a shortage of yellow fever vaccine in Canada, attributed to the difficulty of producing the yellow fever vaccine and need to provide vaccine to residents of countries where yellow fever outbreaks exist. It can take up to six months to produce a batch of usable yellow fever vaccine. Unfortunately when there is an epidemic causing an immediate need to vaccinate a large number of people, manufacturer production capacity can’t meet the global demand.
Where vaccine supply is limited, many clinics have decided to offer fractional doses (eg. one fifth of a dose) to patients requiring the vaccine for travel purposes. Experts advise that a smaller dose of the vaccine can protect people from yellow fever for up to a year – which is suitable for travel. When vaccine supply is no longer limited, experts advise receiving a full dose that provides lifetime immunity against the disease.
Medisys Montreal is among a shortlist of approved travel health clinics in Canada that is able to offer the yellow fever vaccine to travelers. To book an appointment and secure your yellow fever vaccine while supplies last, click here. If you cannot get vaccinated against yellow fever, it may be advisable to consider not travelling to areas with risk of yellow fever transmission.
How to avoid mosquito bites
In addition to yellow fever, depending on the region you are travelling to, mosquitos can transmit a number of other health conditions including malaria, zika, chikungunya, or dengue. Proper anti-mosquito measures can not only help prevent disease, but can also prevent secondary skin infections caused by scratching.
Whether or not you are staying in an area that has been sprayed for mosquitoes, it is still important to wear bug spray and cover up if outdoors during the early morning and late afternoon when Aedes mosquitoes (which can transmit yellow fever, dengue, zika, chikungunya) are most active. Malaria, on the other hand, is transmitted by an evening and night-biting mosquito.
Use insect repellents containing DEET (25-30%) or Picaridin (20%) that are effective for four to 12 hours (depending on the product) and are safe for pregnant women and children over two months of age.
“It’s important to put on insect repellent AFTER you apply sunscreen,” reminds Dr. Jay Keystone, Travel Health Director at the Medisys Clinic in Toronto, “if you want to avoid the double indignity of itchy bites on top of a sunburn”.
Why book a travel health consultation before going abroad
Before travelling somewhere with known risk of disease transmission such as yellow fever, malaria, zika, chikungunya, or dengue (especially if you have an existing health condition) it’s always best to speak with a health professional that specializes in travel medicine.
Individuals with diabetes, respiratory issues, heart conditions, a compromised immune system, babies and young children, or people over 60 all have different travel health needs and depending on your current health status, itinerary, destination, and the specific region of a country you are staying, your risk varies. A particular disease, for example, might be restricted to a few square miles within a particular region of a country.
With a Medisys travel health consultation, you can rest assured you are receiving the best destination-specific, itinerary-specific, and disease risk-specific travel medical advice, medications, and vaccinations (if applicable) to meet your unique needs.
Why come to Medisys for your next travel health consultation?