Western Pacific faces resurgence of measles as immunisation efforts come under pressure

The Western Pacific region is experiencing a resurgence of measles, testing the resilience of immunisation programmes amid coverage gaps and pandemic disruptions, with countries striving to meet ambitious elimination goals by 2030.

Measles, long pushed to the margins of public health in the Western Pacific, is returning as a test of whether countries can still protect hard-won gains. According to the World Health Organization, the region recorded a sharp rise in cases between 2022 and 2023, while coverage gaps, weak surveillance and post-pandemic disruptions left millions of children without routine protection. The agency has warned that transmission can quickly rebound when vaccination rates fall below the level needed to stop outbreaks.

That warning matters because measles is not just another childhood illness. It is one of the most contagious viruses known, and the region’s experience shows how fast it can travel across borders when communities are under-immunised. The US Centres for Disease Control and Prevention has said outbreaks can spread in any population where vaccination is incomplete, and that international movement can carry the virus from one country to another.

WHO has estimated that 3.6 million children in the Western Pacific missed routine immunisations during 2020 to 2022, creating a pool of vulnerability that helped fuel the recent resurgence. In a separate assessment published in April 2026, the agency said progress against vaccine-preventable diseases remains fragile and that community-wide coverage still falls short of the 95% threshold needed to halt measles transmission.

At the same time, the global immunisation strategy that WHO launched in 2020 remains the organising framework for the next phase of work. The Immunization Agenda 2030 aims to ensure that everyone benefits from vaccines at every age, while recovering losses from the Covid-19 pandemic and reaching people who have historically been left behind. In November 2025, WHO’s mid-term review said immunisation had saved millions of lives but that most targets remained off track because routine coverage, equity and outbreak prevention still lagged.

There is, however, a clear political signal that governments have not abandoned the goal. At the Seventy-ninth World Health Assembly in May 2026, more than 70 member states and global health partners reaffirmed their support for the agenda, stressing that immunisation must be country-led, tied more closely to primary care and backed by domestic funding. WHO said the message was especially important for fragile settings, where external support cannot substitute for durable national systems.

That point is particularly relevant in the Western Pacific, where health officials are trying to protect a population of 2.2 billion people across highly varied geographies, from dense cities to remote islands. WHO says nine countries in the region that have not yet eliminated measles have been working with the agency and technical experts on how to reach that goal by 2030. The countries involved are Cambodia, China, Indonesia, Laos, Malaysia, Mongolia, Papua New Guinea, the Philippines and Viet Nam.

The challenge is not only to respond when cases appear, but to sustain routine vaccination, surveillance and trust year after year. WHO has warned that emergency campaigns alone cannot hold the line, especially as new births continue to add to the number of children who need protection. It says nearly 20 million children were born in the region in both 2024 and 2025, underscoring the scale of the task.

The region has already shown that long-term coordination can work. WHO points to more than 25 years of polio-free status in the Western Pacific as evidence that political commitment, surveillance and steady investment can deliver results. The question now is whether governments will treat measles in the same way: not as a passing outbreak, but as a measure of whether public health systems are being properly funded, trusted and maintained.