A large outbreak of yellow fever in the Democratic Republic of the Congo has already put millions of people at risk and is threatening to become a major epidemic across neighboring countries, if not all of tropical and sub-tropical Africa.
Yellow fever is a mosquito-borne viral disease that usually does not kill but causes jaundice, pain and disability. As recently as 2015, the World Health Organization (WHO) had reported no yellow fever in West Africa, thanks to the successful and wide use of a very effective vaccine. Save the Children and DRC officials said that if they can’t contain this outbreak, the entire region could soon be swarming with yellow fever.
Though the vaccine is considered by WHO as one of the most effective of all vaccines, there isn’t enough of it to go around. The U.N. announced in June that its supplies were exhausted, and the global supply of the vaccine was running dangerously low.
Despite this, the country’s health ministry will announce an ambitious plan to vaccinate up to half a million people in the capital, Kinshasa, as it attempts to stop the spread of yellow fever across the region.
The DRC has received more than 3 million vaccines to date as part of a regional effort to prevent further outbreak in the region. In neighboring Angola, where the disease has hit hardest, 6 million vaccines were sent to halt the outbreak, with a million going missing.
Kinshasa has been highlighted as an area at increased risk due to its growing population, said Rachel Pounds, head of operations for Save the Children’s Emergency Health Unit, in an interview with Humanosphere. “The size of the population is one of the biggest challenges, it’s a densely populated area,” she said.
Though the disease occurs in both rural and urban areas, it is a challenge without precedent. “This is the first time partners have had to manage such a large outbreak of yellow fever in a dense, urban setting,” said WHO Communication Officer Tarik Jašarević, in a statement.
Conditions in the city are perfect for the rapid transmission of the disease. Save the Children highlights other major factors as reasons for high transmission rates, including the “increased mobility between large cities in Africa” and “new environmental and climactic factors” such as flooding.
With the rainy season set to start in September in the DRC, it is likely to be the perfect breeding ground for mosquitoes carrying the disease. “We need to get this vaccination campaign done as soon as possible so that we can get it done before the rainy season,” Pounds said.
Even in Kinshasa there are problems accessing vaccines. There are only 7 million vaccines available for a campaign that hopes to reach more than 8 million in Kinshasa and more than 3 million along the border with Angola.
WHO recommended that the government of the DRC and its partners use “fractional doses in vaccination campaigns in order to achieve greater coverage with the limited stock available,” said Ebba Kalondo, communications lead for WHO, in an interview with Humanosphere.
Fractional doses use one-fifth of the regular dose of the full vaccine, which can provide immunity for adults for beyond 12 months.
Pounds says that fractional doses are “the best solution that can be found in the short term.” Individual cases would have to be followed up after a year to ensure full coverage against the disease.
But follow-up doesn’t always happen. “It is often a challenge, especially in areas where health services are not as strong as they might be and where communities are not living close to health facilities,” said Pounds.
With the campaign looking to ration remaining vaccines to reach a greater number of people, WHO hopes that health agencies will be able to vaccinate against the diseases with normal doses of the vaccine in the future. “As soon as the vaccine supply situation normalizes, fractional dosing should be replaced by full-dose vaccination.”
Yellow fever vaccine producers have so far been slow to respond to the crisis supplying far below demands. Soon emergency stockpiles of the vaccine will run out. Before the end of these 12 months, the international community must be clearer on how it will meet demands for the vaccine.