April 17, 2017

The 2016 yellow fever outbreak in Angola and the Democratic Republic of the Congo, required mass vaccination of affected people and travelers to these areas against yellow fever. The quantities of vaccine required, in addition to renovation and expansion of the manufacturer’s production facility, created a yllow fever vaccine shortage going into 2017. The current outbreak of yellow fever in Brazil, has also strained existing stock, and Sanofi Pasteur, the manufacturer of yellow fever vaccine, has announced that once exhausted, no additional product will be available until mid-2018. Given the anticipated critical shortage, the US Food and Drug Administration (FDA) has approved the use of an alternate vaccine; Stamaril, to protect against this disease. Stamaril, available in Europe, had not previously been used for US residents and is considered “experimental” by US authorities. Use of this yellow fever vaccine will only be available at a limited number of select clinics throughout the US.

What is yellow fever?

Yellow fever is a mosquito-borne disease that falls under the World Health Organization (WHO) International Health Regulations (IHR) list of pathogens, allowing countries to enact legislation that would protect them against introduction or expansion of this disease. Proof of vaccination against yellow fever, or a certified waiver from immunization is often required at ports of entry. The requirements may change; expand in event of outbreaks and contract once authorities feel it may no longer be a threat, however, the decisions to require vaccine or waiver may fluctuate and travelers should be aware that if visiting endemic countries, onward travel may be impeded if they cannot show proof of immunization or waiver. Immunity is now considered life-time; only one dose of vaccine is required, however, typically, countries requiring proof also require that the vaccine is given at least ten days prior to arrival.

What is the risk of travel to Brazil without immunization?

Yellow fever is often limited to areas with active and ongoing transmission in humans or non-human primates. Until recently, areas in Brazil affected by yellow fever were considered to only be at high risk in rural areas. In 2016, expansion of disease; as indicated by confirmed cases, were reported in areas not typically considered at risk. The Brazilian Ministry of Health began a mass vaccination campaign to limit disease spread and expanded the list of areas where yellow fever vaccination is recommended. The current outbreak has seen a case fatality rate of approximately one in three persons who are infected. Although risk may be reduced with the onset of cooler and drier weather, as well as in areas that have not reported active cases, and more urban areas, the risk cannot be considered zero. Protection against contracting this disease is conferred with adequate immunization performed at least ten days before arrival to a risk area. Additionally, because of the outbreak in Brazil, neighboring countries are insisting upon proof of immunization or waiver, even for travelers just transiting through briefly. These restrictions, under the auspices of IHR, may impede travel by having entry refused, forcible quarantine, or forced vaccination.

How would the yellow fever vaccine shortage affect me?

If planning on travel to any area considered endemic for yellow fever, individuals should seek consultation with a travel medicine profession at least four to six weeks in advance of their departure. Discuss the need for immunization against yellow fever, potential risks of side effects or adverse reactions, and be prepared to show proof of travel. Clinics authorized to administer yellow fever vaccination and provide the requisite proof, are currently giving this vaccine only to those who truly need it, considering the shortage. Preferential vaccination is made to US Government employees, military personnel, and response workers, as well as those whose travel is between ten and 30 days out. Waivers are available and valid for only six months, and may serve as an alternative to immunization for those concerned with onward travel and who would be at very low risk of contracting the disease. Multi-dose vials – five units (doses) – each may be available if group travel is planned and group consultation can be arranged. Contacting clinics in advance to ensure availability of single or multi-dose protection against yellow fever is strongly encouraged when making appointments.

What if I don’t get the immunization?

As other mosquito related diseases transmitted throughout areas of Brazil are also very important to consider, diligent use of protective measures against mosquito bites is strongly advised. Frequent application of products containing DEET, use of light colored lightweight clothing covering as much skin as possible, sleeping in accommodations with air conditioning and/or fans to circulate the air, and ensuring that screens on windows and doors are intact, all assist in preventing mosquito bites and related diseases. Duty of care obligations assert that organizations with people going to a risk area on behalf of the organization fully inform them of the risk of contracting diseases. If individuals traveling to or operating in areas with active transmission decline, cannot obtain, or otherwise refuse vaccination, they should be made aware of bite prevention and know to seek medical care immediately for any signs or symptoms related to yellow fever.