US supplies of the yellow fever vaccine are at seriously low levels and may run out by summer, the Centers for Disease Control and Prevention said.
That presents a major risk for non-vaccinated travelers heading to countries where the disease is still prevalent, including Angola, the Democratic Republic of Congo and now Brazil.
The CDC has warned US citizens not to travel without a vaccination.
"Take heed of our warning: Plan ahead. It may be difficult to get this vaccine and if you can’t get it, then you should postpone your trip," said CDC spokesperson Tom Skinner.
Government officials have made plans for emergency importation of an alternative vaccine from Europe called Stamaril which is not yet licensed by the Food and Drug Administration but even this will mean dose rationing throughout the country.
"We’re going from the yellow fever vaccine being available in 4,000 clinics across the country to only 250 clinics. The yellow fever vaccine is really important and we are doing everything we can to make sure people who need it can still get it," Skinner said.
A large outbreak in Africa and more recently in Brazil has seen global supplies of the vaccine rapidly dwindle.
"Right now, we don’t have enough vaccine for everyone in Brazil," said Dr. Anthony Fauci of the National Institutes of Health.
"We’re going to have to make more vaccine and that will take time."
The CDC urged all travelers not to delay and get vaccinated now.
