Africa faces a 3,000-year-old threat. This same threat caused death and destruction in Mayan civilizations in the 1600s, ravaged New Orleans in the 1800s and later claimed more lives among soldiers during the Spanish-American War than combat did. Despite its long history, the 21st century has brought a renewed fight against the long-held enemy of Africa—yellow fever.

Angola, a southwestern African country, experienced an urban outbreak of yellow fever in 2016. In urban outbreaks, where disease spreads from human to human, yellow fever is exceptionally deadly. In the Angola outbreak, yellow fever spread to nearby countries and caused a pressing need for millions of yellow fever vaccine doses. All available vaccines were quickly distributed, making the need to plan for future outbreaks clear.

In response, the World Health Organization, in partnership with Gavi and UNICEF, created the Eliminate Yellow Fever Epidemics (EYE) Strategy in 2017. The EYE Strategy outlines a plan to combat yellow fever through 2026, targeting 40 countries, including 27 in Africa, at the highest risk for yellow fever. The primary objectives of the EYE Strategy are to protect at-risk people, prevent international spread and quickly quell outbreaks. Many successful efforts have been made in the fight against yellow fever in Africa.

Protecting At-Risk People

The primary way to protect people at risk for yellow fever is through vaccination. The yellow fever vaccine is safe, low-cost and grants lifelong immunity. Each dose costs slightly more than $1. The EYE Strategy recommends mass vaccination efforts in high-risk countries. Additionally, the strategy recommends that high-risk African countries include the yellow fever vaccine in their regular childhood vaccination schedules. There is consensus that population herd immunity for yellow fever is between 60% and 80% and therefore, the EYE Strategy aims to have at least 70% of the high-risk population vaccinated.

There have been many efforts to protect at-risk people from yellow fever in Africa. Between 2017 and 2022, more than 220 million individuals in Africa received the yellow fever vaccine, with more than 50 million of those vaccinations administered through campaigns. Nigeria conducted a preventative campaign and vaccinated more than 31 million people. The Republic of the Congo vaccinated 3.6 million people in a campaign in response to an outbreak.

Preventing International Spread

The EYE Strategy outlines ways to prevent the international spread of yellow fever. One strategy is prioritizing vaccination for workers in high-risk industries like oil, mining, construction and forestry. Another way to stop international spread is to require yellow fever vaccination for people traveling to and from high-risk countries. The EYE Strategy also recommends readiness plans with steps for agencies to take during an outbreak. Such plans can ensure authorities are prepared to start reactive mass vaccination campaigns quickly.

African countries have made strides to prevent the international spread of yellow fever. Many African countries with a high risk of transmission have vaccination requirements for travelers. Angola, for instance, mandates proof of yellow fever vaccination for travelers aged 9 months and older. Many countries have also developed outbreak readiness plans to prevent international spread. In 2021, Nigeria published a detailed report of its outbreak responses from 2017 to 2019 and its strategies to improve readiness. This report provides a playbook for other African countries to improve their outbreak responses.

Quelling Outbreaks

The EYE Strategy provides several ways for countries to contain outbreaks. Rapid detection of yellow fever cases is one important strategy. Building and maintaining surveillance networks is critical so agencies can identify yellow fever cases immediately. Well-stocked laboratories are also vital to confirm yellow fever cases. An additional strategy to stop outbreaks is stockpiling vaccines. Authorities can deploy stockpiled yellow fever vaccines during outbreaks and help contain disease spread.

Efforts to thwart yellow fever in Africa have improved outbreak responses. The EYE Strategy’s Laboratory Technical Working Group approved a new yellow fever test kit to speed up detection in 2021. In 2022, laboratories in Uganda, Niger, Chad and Ghana improved their abilities to detect yellow fever through training. The EYE Strategy’s Incident Management Support Team provided education on optimizing surveillance and outbreak responses in 10 African countries in 2022.

EYE Strategy Midpoint

The EYE Strategy reached the midpoint of its timeline in 2022. So far, its efforts have resulted in major successes in fighting yellow fever in Africa, including hundreds of millions of vaccinations and improved outbreak readiness.

Despite these successes, more than 10 African countries reported cases of yellow fever in 2022. The work continues to improve yellow fever in Africa.

– Kelly Carroll
Photo: Flickr