From Sewage Sample to Swift National Action: How Uganda Stopped a Silent Polio Threat

23 June 2026

In May 2026, Uganda formally closed a polio outbreak that had been detected two years earlier, marking a major public health achievement and demonstrating the power of preparedness, coordination, and rapid response.

The story, however, began quietly.

On an ordinary Tuesday morning in May 2024, Edward Nyongesa Juma stood at the Doko Sewage Treatment Plant in Mbale City, carrying out a routine task. As a surveillance officer, he collected a monthly environmental sample, part of a nationwide system designed to safeguard Uganda's polio-free status. Nothing about that moment suggested the significance of what he held.

Three weeks later, on May 31, 2024, Uganda's national polio laboratory confirmed the presence of circulating vaccine-derived poliovirus type 2 (cVDPV2) in the sample. There were no reported human cases, no visible signs of illness, but the virus was there, genetically linked to strains circulating beyond Uganda's borders.

For a country that had eliminated polio, the finding was a warning.

Within five days, the Ministry of Health declared an outbreak, setting in motion one of the country's fastest and most coordinated public health responses.

Racing Against Time
The response unfolded with urgency. Within 24 hours of laboratory confirmation, national teams were mobilized. By 1st June 2024, coordination meetings were already underway, bringing together district health officials, national authorities, and international partners.

At the centre of the effort was the Regional Emergency Operations Centre, working alongside the World Health Organization, UNICEF, Rotary International, and the Bill & Melinda Gates Foundation. Together, they established a unified command structure that emphasized clarity and speed.

As one Mbale health official later explained, everyone understood their role from the outset, allowing the system to move quickly and without duplication of effort.

Mapping the Risk
The priority was to determine just how far the threat could spread.

Investigation teams moved swiftly through communities linked to the sewage system, assessing 37 health facilities in Mbale City, reviewing immunization records, and identifying gaps. What they found painted a worrying picture. Only 20 percent of children had vaccination cards, and many had never received routine immunization. Surveillance gaps were also evident, with several districts reporting no cases of acute flaccid paralysis, a key indicator for detecting polio transmission.

Environmental conditions further heightened the risk. Broken drainage systems and wastewater leakage into residential areas created potential transmission pathways. Mbale's role as a regional transport and trade hub, connecting Uganda to Kenya, South Sudan, and the Democratic Republic of Congo, made the city particularly vulnerable, transforming mobility into a potential driver of spread.

By mid-June 2024, it was clear that the response could not remain localized. Authorities expanded operations to cover four high-risk subregions: Mbale, Teso, Karamoja, and Busoga.

A Nationwide Mobilization
With the scale of risk defined, Uganda moved quickly into a nationwide response.

Two rounds of supplementary immunization campaigns were conducted in October and November 2024, using the novel oral polio vaccine type 2. The campaigns reached millions of children under five, including those in hard-to-reach and mobile communities. Health teams went door-to-door, ensuring that even the most vulnerable populations were covered.

The reported vaccination numbers exceeded expectations, reflecting both the intensity of the effort and the effectiveness of community mobilization. The first round vaccinated 2.77 million children, meeting the target, while the second exceeded expectations by reaching 3.13 million children, 14 percent above target, suggesting that even hard-to-reach and mobile populations were successfully covered. Monitoring data suggested that a vast majority of households had been reached, though officials acknowledged that population estimates used for planning may have underestimated the true numbers on the ground.

Beyond Polio
As the response unfolded, it revealed broader gaps in child health.

During house-to-house visits, health teams identified suspected measles cases, particularly among unvaccinated children in Mbale City and Manafwa district. Laboratory tests later confirmed outbreaks. Rather than treating polio and measles as separate emergencies, authorities integrated their response, delivering measles vaccines alongside polio immunization efforts.

This shift reflected an important lesson: children missed by one vaccination program are often missed by others. Addressing one disease effectively required addressing all of them.

The integrated approach also strengthened the wider health system. Health workers received focused training, supply chains were strengthened with partner support, and underperforming facilities were closely supervised and supported to improve service delivery.

Measurable Impact
Within 150 days, the impact of these efforts became clear.

No ongoing transmission was detected through AFP surveillance. At the same time, case detection improved markedly, increasing from 36 baseline cases to 227 during the response, a 531 percent rise that reflected enhanced surveillance sensitivity rather than a true increase in disease incidence. Immunization coverage rose, emergency operations centres remained functional, and health facilities showed lasting improvements.

These gains ultimately led to a key milestone. In May 2026, an independent assessment confirmed that Uganda had met all World Health Organization standards required to close the outbreak.

The Silent System Behind the Success
Central to Uganda's success was a dual surveillance strategy.

Environmental surveillance, such as the routine sampling conducted by Juma, allows health officials to detect the virus before it causes disease. At the same time, indicator-based surveillance tracks symptoms in communities, identifying potential cases for laboratory confirmation.

Together, these systems provide an early warning mechanism, enabling action before an outbreak can escalate.

Vigilance Without Complacency

Today, life at the Doko Treatment Plant has returned to routine. Juma continues to collect his monthly samples, aware that this quiet work plays a critical role in protecting public health.

Across the country, the systems strengthened during the outbreak remain active. Partnerships have been reinforced, and broader immunization campaigns are underway. Yet health officials remain cautious.

Polio has not been eradicated globally, and as long as the virus exists anywhere, countries like Uganda remain at risk, particularly those with high levels of cross-border movement.

A Lesson in Preparedness
Uganda's experience highlights a fundamental truth about infectious disease outbreaks: they often begin silently.

In this case, a single sewage sample revealed a hidden threat. Because surveillance systems were in place and response mechanisms were ready, that threat was contained before it could result in widespread illness or loss of life.

The outcome reflects years of investment in health systems, coordination, and preparedness. When the moment came, the country was ready to act.

In an increasingly interconnected world, where infectious diseases can spread rapidly and without warning, Uganda's response stands as a powerful reminder that strong systems and decisive action can stop even the most invisible threats before they take hold.

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