WHO urges Western Pacific nations to close immunization gaps as coverage slips

Nurse supervisor Melaia Tuiwara packs extra clothes before each boat trip to Fiji's Yasawa Islands, knowing the seas might trap her overnight. She carries vaccines to communities so remote that rough water is the only way in. When her daughter asks why she keeps going, Melaia's answer is simple: it's her calling. Thousands of kilometres away in Merauke, Indonesia, school principal Sister Monica Simarmata sits with parents who have questions about vaccination, bringing them together with health workers so families can ask directly. Local Papuan teachers help translate not just language but culture and trust. One woman crosses water to deliver protection. The other builds the ground where protection can take root. Both are fighting the same battle across a region that has achieved remarkable things—and is now watching those gains slip away.

The Western Pacific has held polio-free status for more than a quarter-century. Twenty-nine countries and territories have eliminated measles and rubella entirely. Thirty-five have introduced HPV vaccination programmes that protect against cervical cancer. These are not small victories. They represent decades of work by people like Melaia and Sister Monica, by health systems that learned to reach the unreachable. But in 2025, nearly 1.7 million babies born in the region—roughly one in every eleven—did not receive even a single routine vaccine dose. Coverage with three doses of diphtheria, tetanus and pertussis vaccine, the standard measure of how well immunization systems actually function, collapsed from 94 percent in 2019 to 89 percent in 2025. Measles, one of the most contagious diseases known, is resurging in parts of the region.

Measles is a revealing disease. It finds the cracks in any immunization system almost immediately. In a region as interconnected as the Western Pacific, a gap in one place becomes a risk everywhere. All twenty-nine countries and territories that had eliminated measles and rubella are still holding that status, and nine more are working toward elimination by 2030. But you cannot sustain elimination through emergency catch-up campaigns alone. You need health workers who can reach communities consistently. You need reliable vaccine supplies. You need surveillance systems and laboratories that work. You need good data. You need people to trust the system enough to show up. "Behind every outbreak is a gap," said Dr Saia Ma'u Piukala, WHO Regional Director for the Western Pacific. "A missed child, delayed action, weakened trust, or communities not reached through regular vaccination programmes."

What makes this moment different is that countries increasingly know exactly where those gaps are. They know which communities are being missed. They know where the bottlenecks sit in their supply chains. They know what needs to be done. The problem is not ignorance anymore. The problem is turning knowledge into action when governments face competing priorities and global health financing has become unpredictable. Immunization is not just about childhood protection anymore either. Vaccines now protect people at multiple stages of life—adolescents through HPV vaccination, pregnant women, adults, older people. As populations age and new vaccines become available, countries have a chance to extend protection across the entire lifespan. But that requires investment at a moment when money is tight and priorities are crowded.

The investment case itself is substantial. Since 1974, vaccination has prevented an estimated 154 million deaths globally. Measles vaccination alone accounts for roughly 94 million lives saved, including an estimated 12 million in the Western Pacific region. From October 19 to 22, representatives from Ministries of Health across the region will gather in Manila for the seventy-seventh session of the WHO Regional Committee for the Western Pacific. Immunization will be one of four main agenda items. A proposed Regional Plan focuses action through 2030 around three connected priorities: reducing the number of children who receive no vaccines or incomplete vaccination; achieving and sustaining measles elimination; and extending immunization across the entire life course. The plan also emphasizes sustainable national financing, investment in the systems needed to deliver vaccines reliably, and greater cooperation between countries.

The next chapter of immunization in the Western Pacific is not about starting from scratch. It is about protecting what has already been achieved, reaching the children and communities still being missed, and making sure the benefits of vaccination reach every generation. For Melaia, that means continuing to pack extra clothes and board boats to remote islands. For Sister Monica, it means continuing to sit with parents and help them understand. For the region, it means turning the knowledge of where the gaps are into the resources and systems to close them.