Mpox in Sierra Leone and the Mano River Union: an epidemic unfolding in real time

Abstract

The 2025 mpox outbreak in Sierra Leone represents an unprecedented public health crisis, escalating rapidly from minimal prior cases to over 4400 confirmed infections within 6 months. This surge challenges previous assumptions about mpox epidemiology in West Africa and highlights critical vulnerabilities in disease surveillance, diagnostics and health system preparedness—challenges shared across the Mano River Union (MRU) region, including Liberia, Guinea and Côte d’Ivoire. Despite global commitments to equitable vaccine access, Sierra Leone and its neighbours have faced significant delays and fragmented mpox vaccine deployment, reflecting systemic failures in global health financing, vaccine ecosystems and governance. In this analysis, we examine the demographic and geographic features of the outbreak within Sierra Leone and the MRU, operational challenges and the urgent need for a coordinated equity-driven regional response. In doing so, we call for targeted vaccination, decentralised testing, the integration of mpox control into sexual health programmes and the strengthening of African vaccine manufacturing capacity. The outbreak underscores the necessity of rethinking global health governance to ensure timely sustained support for endemic and interconnected regions.

Summary box.

• Sierra Leone is experiencing an unprecedented clade IIb mpox outbreak in heterosexual network, with over 4400 confirmed cases by June 2025, representing the largest documented mpox burden in West Africa and signalling elevated risk across the Mano River Union (MRU) region.

• The outbreak exposes severe weaknesses in surveillance and diagnostics, delayed case detection and fragile response capacity, particularly in dense urban settings such as Freetown, with cross-border mobility amplifying regional transmission risk.

• Structural health system constraints, stigma and the absence of integrated sexual and reproductive health services are likely enabling sustained and undetected transmission within highly mobile and interconnected populations across the MRU.

• Despite global commitments to vaccine equity, mpox vaccination in Sierra Leone has been minimal, with only around 43 000 individuals receiving a dose. This shortfall reflects deeper structural dependence on external vaccine supply and the absence of African manufacturing capacity, limiting timely access across the MRU.

Introduction

Mpox, a neglected zoonotic disease historically endemic to Central and West Africa, has evolved into a complex global health threat.¹ Once confined largely to sporadic Clade I and II infections, the emergence of Clade IIb in 2022—a genetically distinct lineage of the West African clade associated with sustained human-to-human transmission and large urban outbreaks, marked a turning point, driving widespread outbreaks primarily among men who have sex with men in non-endemic regions. This event led the WHO to declare a Public Health Emergency of International Concern (PHEIC), first in 2022² and again in 2024³ as a second emerging variant Clade Ib spread across Central and Eastern Africa.

By mid-2025, mpox transmission had intensified across the African continent, with over 52 000 reported cases and 1770 deaths spanning 16 countries.⁴ On 9 June 2025, the WHO reaffirmed its PHEIC designation, citing the continued cross-border spread, changing transmission patterns and inequitable access to diagnostics, treatment and vaccines.

Until recently, Sierra Leone, one of four countries in the Mano River Union (MRU) alongside Liberia, Guinea and Côte d’Ivoire, had recorded only three confirmed mpox cases between 1970 and 2021.⁵ While serological evidence of Orthopoxvirus exposure in Eastern Sierra Leone suggested latent vulnerability, a marked epidemiological shift occurred in early 2025. Within just 6 months, the country reported more than 4400 confirmed cases, accounting for over half of all new mpox cases on the continent during the first week of June.⁶

The outbreak, driven predominantly by Clade IIb, was centred in the Western Area, including Freetown, where the highest number of cases were reported. The epidemic differs from earlier outbreaks in the region by its urban transmission profile, sustained person-to-person spread and involvement of young adults of both genders in densely populated urban and periurban communities.^{7 8} Although Sierra Leone currently accounts for the largest number of reported cases in the MRU, Liberia and Guinea also faced growing risk.

In this analysis, we examine the mpox epidemic in Sierra Leone within the broader context of the MRU. We explore how historical fragility, underinvestment in health systems and gaps in regional coordination have shaped the emergence and trajectory of the outbreak. We argue that addressing the current epidemic requires not only response at the national level, but also strengthened regional cooperation across the West African subregion.

Historical, structural and political drivers of vulnerability in the MRU

Sierra Leone’s response to the 2025 mpox outbreak was shaped by a long-standing legacy of civil conflict, institutional fragility and regional vulnerability. The country’s 11-year civil war (1991–2002)⁹ caused widespread destruction of public infrastructure and left enduring effects on the health system. This period of instability disrupted essential health services, fractured public trust and entrenched chronic underinvestment, particularly in rural and peri-urban areas where many facilities remain under-resourced.

These structural challenges are mirrored in neighbouring countries, Liberia, Guinea and Côte d’Ivoire, each of which has experienced its own history of civil unrest and governance challenges.^{10 11} Together, these four countries form the MRU, established in 1973 to promote economic integration and regional cooperation.¹² Today, the MRU region constitutes a highly interconnected epidemiological space, characterised by porous borders, frequent cross-border mobility, shared linguistic and cultural ties and underfunded health systems. These factors have repeatedly contributed to the regional spread of infectious diseases (see Box 1).

Box 1. Mpox risk in the MRU region.

The MRU—comprising Sierra Leone, Liberia, Guinea and Côte d’Ivoire, is a high-risk corridor for mpox transmission due to intense cross-border mobility, shared sociolinguistic ties and structurally fragile health systems. Established¹¹ in 1973 to foster regional economic cooperation, the MRU has occasionally been mobilised for health coordination, notably during the Ebola (2014–2016) and COVID-19 outbreaks.

The region forms an interconnected epidemiological space, characterised by porous borders, circular migration and overlapping social networks. Epidemics such as Ebola, Lassa fever and COVID-19 have demonstrated the ease with which infectious diseases transcend national boundaries in this setting.

This epidemiological vulnerability is further amplified by a legacy of armed conflict, institutional fragility and unresolved cross-border tensions. Sierra Leone (1991–2002),⁶ Liberia (1989–2003)⁹ and Côte d’Ivoire (2002–2011)¹⁰ all experienced prolonged civil wars that severely disrupted public health infrastructure and displaced populations. Periodic border disputes,⁵² such as in Yenga between Guinea and Sierra Leone, and concerns about the extradition of alleged coup plotters continue to strain regional relations and challenge cross-border coordination.

Key regional risk factors include:

• High population mobility: Daily informal movement for trade, livelihoods and kinship complicates case tracking, contact tracing and quarantine enforcement.

• Weak border health infrastructure: Screening, triage and case detection capacities remain limited, particularly at informal crossing points.

• Shared health system weaknesses: Despite post-Ebola investments, many health systems in the MRU remain underfunded, overcentralised and inadequately staffed.

• Asynchronous outbreak dynamics: As of June 2025, mpox transmission appears uneven across the MRU, raising concern about silent transmission and diagnostic delays.

Mpox Status (as of mid-June 2025):

• Sierra Leone: The most severely affected MRU country, with widespread community transmission.

• Liberia: 69 confirmed cases, predominantly in counties bordering Sierra Leone.

• Guinea: No confirmed cases, though retrospective surveillance capacity remains limited.

• Côte d’Ivoire: No reported cases; however, risk remains high due to proximity and population movement.

• Ghana (non-MRU): 98 confirmed cases, underscoring the broader West African risk.

Implications

Coordinated MRU-level preparedness and surveillance strategies—including joint case investigation protocols, information sharing mechanisms and cross-border vaccination campaigns—are urgently needed. Lessons from past Ebola coordination efforts should inform a more agile, decentralised and trust-based regional response to mpox.

The 2014–2016 Ebola virus disease outbreak,¹³ which began in Guinea and spread rapidly across Liberia and Sierra Leone, exposed systemic weaknesses throughout the MRU. However, it also prompted significant public health reforms. In Sierra Leone, for example, the outbreak led to the establishment of the National Public Health Agency (NPHA), improvements in disease surveillance and the development of community-based event monitoring and decentralised response mechanisms.^{14 15} Similar reforms were introduced across the MRU, often with support from the West African Health Organisation (WAHO), the WHO and the Africa Centre for Disease Control and Prevention (Africa CDC).

Despite these advances, significant structural constraints remain. Health systems in the MRU continue to suffer from underfunding, limited access to care, centralised service delivery and weak cross-border coordination. These limitations have once again become evident during the mpox outbreak. While Sierra Leone has reported the highest number of confirmed cases, Liberia also experienced significant transmission and the risk of cross-border spread to Guinea and Côte d’Ivoire remains substantial. The porous land borders and fluid population movement within the MRU underscore the region’s shared vulnerability.

Moreover, political instability across the MRU compounded these challenges. For example, Sierra Leone experienced a failed coup attempt in late 2023,¹⁶ followed by ongoing prosecutions and heightened security concerns, while Guinea remain under military rule following its 2021 coup, with a delayed transition to civilian governance.¹⁷ Such political volatility risks disruptiion of health service delivery, weakening public trust and declining donor confidence. These disruptions pose challenges to regional cooperation necessary for coordinated surveillance, data sharing and joint outbreak response, elements essential to effective mpox control.

In this context, national responses, though essential, are insufficient in isolation. Effective epidemic preparedness and control require coordinated regional approaches that include harmonised surveillance systems, data sharing protocols, pooled procurement mechanisms and joint outbreak response. The MRU’s collective experience during the Ebola epidemic provides a precedent for such collaboration, but the existing frameworks have not yet been fully mobilised in response to mpox. Without addressing these interconnected drivers of vulnerability, efforts to control current and future outbreaks will remain fragmented and inequitable.

Mpox in Sierra Leone: an unprecedented and underestimated crisis

The 2025 mpox outbreak in Sierra Leone represents a fundamental shift in the regional dynamics of a disease historically considered rare within the country. Between 1970 and 2021, only three confirmed cases had been reported.⁵ However, this changed dramatically with the confirmation of the first mpox case on 10 January 2025.

Retrospective investigation later identified the index case: a young man aged between 26 and 35 years from a rural area near Lungi who fell ill in December 2024. He disclosed living with HIV and reported no history of international travel. However, during that period, he travelled to Lungi, where he engaged in unprotected sexual intercourse with a sex worker.⁶ Initially misdiagnosed and treated for malaria, he only received a correct mpox diagnosis weeks later, after seeking care from both health workers and traditional healers. His case marked the start of what would become Sierra Leone’s largest recorded mpox outbreak.

Lungi, home to Sierra Leone’s principal international airport, is connected to Freetown, the capital, by a frequent and heavily used ferry service, facilitating close daily contact and easy movement between these two population centres. While Lungi itself does not share land borders with neighbouring countries, its role as a transport hub and its close connectivity to Freetown mean infected individuals can rapidly move into the densely populated capital, accelerating transmission.

In the subsequent months, Sierra Leone has experienced a rapid and unprecedented surge in infections, culminating in over 4000 confirmed cases by June, placing Sierra Leone as the third highest-burden country in Africa for mpox this year, following the Democratic Republic of Congo and Uganda.

In response, the Government of Sierra Leone, through the Ministry of Health and the NPHA, initiated coordinated interventions to contain the outbreak and mitigate its impact.¹⁸ These developments have challenged long-standing assumptions about mpox epidemiology in West Africa and have exposed critical vulnerabilities in disease surveillance systems, laboratory diagnostic capacity, and broader infrastructure for PPPR.

Geographic and demographic patterns

The epicentre of the current outbreak is Freetown, Sierra Leone’s capital, home to over 1.4 million people.⁶ The urban concentration of cases mirrors trends seen in Nigeria and the 2022 global outbreak, where Clade IIb MPXV propagated rapidly in high-density settings with complex human mobility and social networks. Although detailed epidemiological disaggregation remains incomplete, preliminary reports indicate that a number of identified cases have occurred among young adults, particularly women, with possible sexual transmission playing a role.⁵ These patterns are broadly consistent with observations from the 2022 outbreak among gay, bisexual and other men who have sex with men, as well as heterosexual transmission networks documented in Nigeria.^{19 20}

Although Freetown remains the outbreak’s epicentre, cases have been confirmed in all 16 districts, signalling widespread geographic diffusion. This national spread is compounded by regional mobility patterns. Within the MRU, Sierra Leone shares extensive and frequently crossed borders with Liberia and Guinea. Liberia had recorded 69 cases by early June 2025; Guinea, while not yet reporting confirmed cases, remains at high risk due to informal trade, familial networks and porous borders.²¹ Côte d’Ivoire, too, faces elevated risk due to shared borders and recent political fragility. Ghana, a key regional hub for mobility and trade, had reported 98 cases by mid-June—suggesting Clade IIb’s movement along established migration corridors.²²

While the outbreak in Sierra Leone and much of the MRU has been driven predominantly by Clade IIb, the broader African mpox landscape is becoming increasingly complex. Several countries in Central and Eastern Africa have experienced sustained transmission of Clade Ia and Ib,^{23 24} while emerging genomic evidence suggests the co-circulation of multiple mpox clades and subclades in some settings. These developments may influence transmission patterns, affected populations and surveillance priorities, underscoring the importance of strengthening genomic surveillance, laboratory capacity and regional data-sharing systems. Preparedness strategies should therefore remain adaptive to an evolving epidemiological landscape rather than assuming a uniform pattern of transmission across the continent.

Within Sierra Leone, available evidence continues to suggest that social and sexual networks may play an important role in transmission. However, targeted sexual health services and tailored risk communication strategies remain limited.²⁵ The potential for widespread undetected transmission through social and sexual networks is significant, particularly in the context of HIV, limited sexually transmitted infection (STI) services and deep-rooted human rights barriers to access health services by female sex workers, which may deter care-seeking and contact disclosure. These social factors, coupled with health system challenges, risk sustaining and expanding transmission within and beyond identified networks.

Surveillance, testing and health system fragility

Despite post-Ebola reforms, mpox surveillance in Sierra Leone remains severely constrained. Reported test positivity rates exceeded 90% in several districts during samples collected between March and May 2025, reflecting highly selective testing focused on individuals with advanced symptoms.²⁶ This high threshold for testing likely obscures a broader reservoir of undiagnosed infections and hinders early detection efforts. Centralised laboratory services and protracted turnaround times further compound diagnostic delays, impeding timely response and effective case management.²⁷

These limitations reflect a broader continental pattern. In the Democratic Republic of the Congo, a country with decades of experience with mpox, only 27% of suspected cases were tested in early 2025, underscoring frequent gaps between clinical suspicion and laboratory confirmation even in high-burden settings.²⁸ This highlights systemic diagnostic fragility not only in emergent epicentres like Sierra Leone but also across mpox-affected countries in Africa.

In an effort to strengthen surveillance, the Sierra Leone NPHA launched the ‘Find Them All’ campaign in February 2025.²⁹ This active case-finding initiative sought to reach communities beyond the formal health system and marked a strategic pivot from passive, facility-based detection to community-level engagement. Yet, its implementation has faced major hurdles, including logistical bottlenecks, inadequate testing supplies and community hesitancy, which have limited its impact.³⁰

Clinical care capacity has seen notable expansion. In May 2025, a 400-bed mpox treatment centre was inaugurated at the Police Training School in Hastings, with plans to scale up to 950 beds.³¹ A separate 50-bed facility was opened in Calaba Town, Freetown, in collaboration with Médecins Sans Frontières Belgium.³² These facilities represent critical progress in building national treatment infrastructure.

However, operational challenges remain substantial. An Africa CDC-led assessment in April 2025 found that the health system remained overstretched, with insufficient staffing, limited operational funding and logistical barriers hampering the functionality of newly established treatment centres.³³ As a result, many patients have continued to receive care at home, complicating isolation and contact tracing efforts. Public compliance with referrals to treatment centres has also been limited, reflecting low trust, insufficient community engagement and resource constraints affecting implementation of the National Mpox Incident Action Plan.

To translate these infrastructure gains into effective care delivery, targeted investments are urgently needed in risk communication, patient referral systems and flexible operational financing. Strengthening coordination between national health authorities, community leaders and international partners will be essential to improve case management, support safe isolation and sustain response momentum.

Encouragingly, coordinated deployments are beginning to emerge. As of 13 June 2025, 36 AVoHC-SURGE responders, mobilised through the joint efforts of the government of Sierra Leone, WHO, Africa CDC, WAHO and partners, had been deployed to high-burden districts.³⁴ These efforts reflect promising intersectoral collaboration. Yet, to achieve durable epidemic control, further decentralisation of testing, expansion of community health worker networks and real-time data systems will be necessary to interrupt transmission chains and build a resilient response infrastructure.

The vaccine gap: global commitments and local realities

Despite early global commitments to equitable access, Sierra Leone’s experience with mpox vaccination illustrates ongoing challenges in translating global solidarity into tangible, timely support for countries bearing the highest burdens. Vaccination began in March 2025, targeting healthcare workers, people living with HIV, military personnel, university students and known contacts in high-risk districts, including the Western Area.³⁵ As of early June 2025, only 80 000 doses had been delivered nationally, and just over 43 000 individuals had received at least one dose.² Vaccination coverage has increased modestly since this reporting period, though national targets remain unmet. This coverage remains inadequate for effective ring vaccination or broader preventive immunisation in a country facing one of the largest mpox outbreaks on the continent.

Sierra Leone’s constraints are emblematic of a broader regional challenge. In September 2024, the Africa CDC and WHO launched a continental mpox preparedness and response plan, aiming to vaccinate 10 million of the 13 million people identified as eligible across Africa within 6 months.³⁶ However, by 29 May 2025, only 720 000 individuals had received a dose, reflecting severe shortfalls in supply, operational coordination and financing.²⁷ The misalignment between vaccine allocation and evolving epidemiological risk, as seen in Sierra Leone, raises urgent questions about responsiveness and equity in global procurement frameworks.

Prohibitive costs have further stymied progress. With mpox vaccines priced at over $100 per person, comprehensive coverage remains financially out of reach for most affected countries and even stretches the capacity of global health partners.^{37 38} These economic barriers reinforce existing logistical bottlenecks, but they also reflect deeper structural inequities.

The root causes extend beyond cost or coordination. Global vaccine supply chains have become increasingly vulnerable to geopolitical and financing uncertainties. Recent shifts in US global health engagement, including reductions in support for the US Agency for International Development and WHO, as well as delays in fulfilling vaccine commitments, have contributed to broader challenges in global outbreak preparedness and response.³⁹ These developments have compounded funding constraints affecting epidemic response infrastructure and essential health services in many affected countries.

At the same time, the global vaccine manufacturing ecosystem remains highly unequal. Bavarian Nordic, the sole producer of the Modified Vaccinia Ankara-Bavarian Nordic vaccine, has entered a technology transfer agreement with the Serum Institute of India.⁴⁰ This demonstrates the feasibility of decentralised production. Yet no such agreement has been extended to African manufacturers, despite repeated calls to enhance regional autonomy.⁴¹ The COVID-19 pandemic laid bare the consequences of this dependence: Moderna and Pfizer’s refusal to share messenger RNA vaccine technology with African partners delayed regional capacity-building and access.⁴²

While the Africa CDC has articulated plans to establish vaccine manufacturing hubs, progress has been slow, hampered by opaque licensing arrangements, weak donor commitment and limited cooperation from multinational corporations.⁴³ Without deliberate efforts to deconcentrate manufacturing and prioritise African-made vaccines within global procurement systems, countries like Sierra Leone will remain at the end of the line.

Equity in vaccine access cannot remain an afterthought or emergency-time improvisation. It must be recognised as a structural priority, anchored in regional capacity, long-term financing and inclusive governance to stop epidemics when and wherever they occur.⁴⁴ Building African vaccine manufacturing is not only a question of health security but also of sovereignty and sustainability. Donor countries and global agencies must move beyond charity-based models and invest in durable long-term capacity. Unless this shift occurs, future epidemics will once again expose and amplify existing inequalities, leaving frontline countries to wait for life-saving tools.

Rethinking global health governance in an era of fragmentation

The entrenchment of Clade IIb mpox across multiple African countries, and the continued spread of Clade I in Central Africa, exposes enduring failures in global outbreak preparedness and response. Sierra Leone’s unfolding mpox crisis underscores how systemic gaps in diagnostics, surveillance, vaccine distribution and health system financing continue to undermine equitable epidemic control.

In May 2025, the WHO adopted the Pandemic Agreement,⁴⁵ a landmark commitment aimed at strengthening international cooperation, accelerating data sharing and ensuring equitable access to countermeasures. Yet, as Sierra Leonean physicians Mohamed Bella Jalloh and Mamadu Baldeh have pointedly asked: ‘Why do genetic samples sometimes take longer to cross a district on a motorbike than viral isolates take to reach European labs? And why do vaccine queues sometimes appear to favour the well-connected over those most at risk?’²⁵ These questions cut to the heart of the issue. While global frameworks promote equity in principle, they too often operate within systems that replicate or entrench inequalities.⁴⁶

Bridging this disconnect demands more than aspirational declarations. To realise the promise of the Pandemic Agreement, governments and global institutions must embed accountability, local ownership and equity into the core of governance mechanisms.^47–49 This requires transparent resource allocation, inclusive priority-setting and long-term investment in national health systems and community-led infrastructure.

Critically, the legitimacy of global health governance must be measured not by the adoption of agreements but by their on-the-ground impact. Do vaccines, diagnostics and therapeutics reach those who need them mostat the time they are needed? Are frontline responders empowered, resourced and represented in decision-making spaces? Without demonstrable improvements in equity and access, there is a risk that global commitments may not translate into meaningful outcomes for the populations they are intended to serve.

The mpox epidemic in Sierra Leone, like Ebola before it, is not simply a national crisis, it is a stress test for global health governance writ large. If the lessons of mpox are not acted upon with urgency and humility, the next pandemic will once again reveal the same fault lines, with consequences that extend far beyond any single country’s borders.

Call to action: reversing neglect and building a resilient response

The 2025 mpox outbreak in Sierra Leone is a stark indictment of global health systems that continue to deprioritise equity, proactive surveillance and sustained investment in endemic regions. While Clade IIb mpox initially drew international attention due to outbreaks among male sexual networks in high-income countries, its unusual manifestation as a heterosexually transmitted disease spreading in low-resource, high-density settings like Sierra Leone is proving more devastating, yet remains dangerously under-recognised.

Prioritise emergency vaccine access and delivery

Despite WHO and Africa CDC commitments to equitable vaccine distribution, Sierra Leone has received only a fraction of the doses required. The Western Area, including the capital Freetown, remains severely underserved despite bearing the highest national burden.

• Emergency vaccine allocations must prioritise Sierra Leone and comparable epicentres, including through ring vaccination, frontline health worker protection and immunisation of high-risk groups.

• Vaccine delivery must be paired with operational funding to support last-mile logistics, cold chain systems and community engagement.

Strengthen surveillance, diagnostics and community-led response

A national test positivity rate of over 90% is less a marker of diagnostic success than a sign of systemic failure. Early case identification remains limited, especially outside urban centres.

• Decentralised testing capacity must be urgently scaled to include rural and under-resourced districts.

• Community health workers, instrumental during past epidemics, should be re-engaged to support syndromic screening, contact tracing, home-based care and risk communication.

• Investments in digital surveillance tools are essential to enable real-time case tracking and interdistrict coordination.

• Cross-border surveillance and information-sharing must be synchronised across MRU countries. Joint testing protocols, alerts and simulation exercises are critical to pre-empting regional spread.

Integrate Mpox into sexual and reproductive health services

Different from the 2022 global outbreak, the current epidemic in Sierra Leone reflects heterosexual transmission patterns involving sexual networks.

• Risk communication must be inclusive, evidence-based and destigmatising, particularly for vulnerable populations such as sex workers, students, truck drivers, people living with HIV and LGBTQ+ communities.

• Mpox screening and vaccine prevention should be integrated into existing HIV and STI programmes to enable syndromic surveillance, timely treatment and broader sexual health service strengthening.

Reform global health governance and emergency response criteria

The continued spread of Clade IIb and Clade Ib mpox across Africa highlights persistent inequities in how global health crises are defined and addressed.

• WHO and global funders must revise emergency response thresholds to ensure sustained support for high-burden, low-visibility outbreaks.

• The PHEIC mechanism should include automatic triggers for funding, vaccine access and technical support for affected countries regardless of media attention or geopolitical influence.

Invest in African vaccine manufacturing and autonomy

Long-term mpox control will depend on building sustainable, regional capacity for vaccine and diagnostic production.

• Africa CDC’s initiative to expand African manufacturing hubs must be accelerated through technology transfer agreements, strategic investment and long-term financing mechanisms.

• Global procurement mechanisms must actively support African-made countermeasures to ensure equitable access, strengthen regional markets and reduce dependency on external suppliers during public health emergencies.

• Regional and national investments in manufacturing should be complemented by strengthened laboratory networks, supply chains and procurement systems to ensure that locally produced vaccines and diagnostics can be rapidly deployed during outbreaks.

Leverage the African epidemics fund and regional frameworks to scale response

The African Union’s launch⁵⁰ of the African epidemics fund (AEF) marks a critical step towards African-led health security, but its impact hinges on rapid operationalisation and alignment with regional response needs.⁵¹

• The AEF must be deployed as a primary financing tool for high-burden countries like Sierra Leone, enabling timely funding for vaccine procurement, logistics and community health workforce support.

• The Africa CDC and WAHO should serve as regional coordination leads—harmonising outbreak data, activating AVoHC-SURGE response teams and driving pooled procurement of vaccines and diagnostics.

• MRU countries must strengthen joint outbreak planning, simulation exercises and cross-border coordination to contain spread.

• Donors and international partners should commit to matching AEF contributions to ensure its sustainability and autonomy.

Conclusion

The mpox outbreak in Sierra Leone is more than a national public health emergency. It is a regional warning for the MRU and a reminder that epidemic threats exploit the same structural weaknesses that have shaped previous health crises across West Africa. Once considered a rare and geographically limited disease, mpox is now demonstrating its capacity to spread through sexual networks in densely populated urban centres and across highly connected border regions, exposing persistent gaps in surveillance, diagnostics, vaccination and outbreak preparedness.

The trajectory of the outbreak underscores that epidemic control cannot be achieved through national responses alone. For the MRU countries, effective PPPR will require stronger regional coordination, sustained investment in public health systems and the operationalisation of mechanisms for cross-border surveillance, information sharing and rapid response. Equally, the outbreak highlights the continued consequences of inequities in access to vaccines, diagnostics and financing that leave affected countries responding with limited tools during periods of escalating transmission.

Ultimately, Sierra Leone’s experience should be viewed not as an isolated event but as a test of whether lessons from Ebola, COVID-19 and mpox can be translated into more resilient and equitable systems for PPPR. The measure of success, therefore, will not be the adoption of new commitments but whether countries at the front line of outbreaks are equipped with the resources, authority and support needed to detect, contain and respond to emerging threats before they become regional or global crises.