Brazil's health ministry has ordered 11.5 million doses of yellow fever vaccine amid the largest outbreak of the disease in the country since 2000, according to BBC.
Seventy cases - including 40 deaths - are confirmed, mostly in rural areas of the state of Minas Gerais.
More than 300 cases are under investigation.
Vaccinations are being recommended for people travelling to Minas and other areas with confirmed cases.
Yellow fever is a potentially fatal disease transmitted by mosquitoes.
Most of Brazil is considered at risk from yellow fever but the country has only seen a handful of cases in recent years.