United States Response to the Clade I Mpox Outbreak in Several African Countries

On August 14, 2024, the World Health Organization (WHO) declared a Public Health Emergency of International Concern about the upsurge of mpox cases in the Democratic Republic of the Congo (DRC) and a growing number of countries in Africa.  This announcement followed the Africa Centres for Disease Control and Prevention’s (Africa CDC) declaration of a Public Health Emergency of Continental Security on August 13.  The significant increase of clade I mpox cases, in both endemic countries (those that have previously had mpox outbreaks) and non-endemic countries (those that have historically not reported mpox outbreaks), threatens the health security of the region, as well as countries outside Africa.  In addition, clade I mpox has a newer sub-clade referred to as clade Ib. Both clade Ia and clade Ib are circulating in DRC and have been detected in neighboring countries and in Sweden and Thailand (one case each associated with travel to Africa with known clade I cases).

In 2022, the world experienced a global outbreak of clade IIb mpox, which led to more than 95,000 cases across 115 non-endemic countries and continues to occur in the United States.  The Biden-Harris Administration responded by ensuring the JYNNEOS mpox vaccine was available to at-risk populations in the U.S.

In February, as the clade I mpox outbreak grew in DRC, the Biden-Harris Administration established an incident response structure across federal departments and agencies to ensure a coordinated response and to take a proactive approach to U.S. domestic preparedness for potential clade I mpox cases.  Clade I mpox causes a higher number of severe infections and has a higher mortality rate than clade IIb mpox.  Because evidence for clade I mpox clinical outcomes is based primarily on data from endemic countries without widespread supportive care, particularly DRC, we do not yet know how clade I mpox would impact Americans; we do expect it would cause lower morbidity and mortality in the United States.

United States preparedness for clade I mpox

The Biden-Harris Administration has been closely monitoring the spread of mpox, specifically clade I mpox, and has been working since December 2023 to prepare domestically.  The risk to most Americans from clade I mpox circulating in Central and Eastern Africa and the travel associated cases outside of Africa is very low, and there are no known cases in the United States at this time.  The United States is well prepared to rapidly detect, contain, and manage clade I cases should they occur domestically.

The United States continues to increase our capacity to detect cases of clade I and clade IIb mpox through existing surveillance systems, including wastewater testing, and through expanding the robust diagnostic testing capacity built during the ongoing clade IIb outbreak to ensure coverage for clade I.  The ability to expedite such diagnostic testing—in particular for those with recent travel to DRC or neighboring countries—also supports rapid detection.  In addition to reaffirming the importance of mpox vaccination for those who are eligible, we are working to prevent the spread of both clades of mpox by providing and disseminating recommendations for clinicians, health departments, diagnostic laboratories, and the public.

From August 2022 to August 2024, the Administration for Strategic Preparedness and Response (ASPR), part of the Department of Health and Human Services (HHS), distributed more than one million vials of the JYNNEOS vaccine across the United States to mitigate the spread and severity of the clade II mpox outbreak.  In addition to the preventive vaccine, partners across the U.S. government are working to better understand the effectiveness of existing treatments for mpox and have treatment options available in the event that clade I mpox is reported in the United States.  The United States will continue to provide information to the public on transmission, prevention, and treatment of mpox.  Those who have already had clade IIb mpox or who are fully vaccinated against it are expected to be protected against clade I mpox.

CDC has issued an updated Health Alert Network advisory for clinicians and public health departments and partners, as well as an updated Travel Health Notice, recommending travelers to DRC and neighboring countries to practice enhanced precautions.  Through the State Department, our embassies are working to keep U.S. citizens abroad informed of these updates.  At this time, CDC and WHO do not discourage travel to DRC or elsewhere due to the mpox outbreaks.

United States support to the global mpox outbreak

The U.S. government has been closely monitoring the spread of clade I mpox in DRC and the risk to neighboring countries since 2023, and we have been working closely with the affected country governments and regional and global health partners to reduce the impact of this outbreak and safeguard public health.  The U.S. government support for the mpox response builds on our longstanding partnerships in global health security and development with DRC and throughout Africa, which have helped to combat infectious diseases, such as HIV, tuberculosis, and malaria for more than 20 years.  In fiscal year 2023, the United States allocated more than $2.65 billion in bilateral health funding to countries in Central and Eastern Africa and is the largest global health donor.

Since March 2024, USAID and CDC together have provided an additional $20 million USD to support clade I mpox response efforts in Central and Eastern Africa, and on August 20, USAID announced up to an additional $35 million in emergency health assistance to bolster response efforts, pending Congressional Notification, bringing the proposed total U.S. government financial support for DRC and other affected countries in the region to more than $55 million.

In addition to direct financial support, the United States government is surging staff to support the mpox response.  More than 200 staff including epidemiologists, laboratorians, and risk communication experts have been deployed to support response efforts in the United States and Africa.  United States government support has focused on a range of critical public health interventions aimed at limiting transmission and reducing mpox morbidity and mortality.  These interventions include surveillance with deployment of additional local field epidemiologists, risk communication and community engagement, laboratory supplies and diagnostics, infection prevention and control, clinical services, and vaccine planning.

In addition to scaling up surveillance, testing, and treatment of cases, vaccination will be a critical element of the response to this outbreak.  Successful vaccination campaigns will require health workers to provide vaccinations, financial support to roll out vaccine and vaccination supplies, and regulatory approval for use of vaccines in affected countries.  To support this effort, USAID is donating 50,000 doses of the FDA-approved JYNNEOS vaccine to DRC, as well as financial support for rollout of the vaccine doses.  The United States is working with other countries that have vaccine stockpiles, WHO, and international partners to encourage additional donations that support vaccine efforts and address challenges with vaccine delivery.  This includes evaluating vaccine demand, supporting country engagement on regulatory pathways, planning vaccine implementation, and providing technical assistance to deliver the vaccines.

The United States is working with bilateral, multilateral, and private sector partners to develop and implement a coordinated response – including encouraging collaboration between WHO and Africa CDC on their response plans.  The United States, through the State Department, will continue working through the U.S.-Africa CDC Joint Action Plan adopted in November 2023 to increase African Union Member States’ capacity to prevent, detect, and respond to health emergencies.

The Biden-Harris Administration will continue its whole-of-government response to this growing outbreak, building on lessons learned from the 2022 mpox response.  To learn more about mpox, signs and symptoms, treatments, and prevention, please visit the CDC website here.