Almost 1.7 million babies born in the Western Pacific in 2025 — roughly one in 11 — missed their first routine vaccine dose, according to the World Health Organization, and the agency is warning that diseases long considered defeated in the region could come roaring back.

The numbers tell a slow slide rather than a sudden collapse. Coverage of the three-dose diphtheria, tetanus and pertussis vaccine dropped from 94 percent in 2019 to 89 percent in 2025. WHO regional director Dr. Saia Ma'u Piukala put it bluntly: behind every outbreak sits a gap — a child missed, a delayed response, eroded trust, or communities that routine programmes simply don't reach.

Measles is where those gaps show up first, because it's one of the most contagious viruses known. Cases in the Western Pacific jumped 743 percent between 2022 and 2024, and imported infections tied to international travel have surfaced in Australia, Hong Kong, Japan, New Zealand, South Korea and Singapore. WHO's message for the region is that an immunity shortfall in one country quickly becomes everyone's problem on a continent criss-crossed by cheap flights.

Nine countries are now chasing measles elimination by 2030, and health representatives will gather in Manila from October 19-22 for the 77th session of the WHO Regional Committee to work through a proposed regional immunisation plan. It focuses on three priorities: cutting the number of unvaccinated and under-vaccinated people, achieving and holding measles elimination, and extending vaccination across whole lives rather than just childhood. The plan also stresses sustainable national funding, dependable vaccine supply chains, solid surveillance and lab networks, and cross-border cooperation — with WHO cautioning that catch-up campaigns alone won't keep elimination on track.

For travellers, this isn't background noise. Measles spreads readily in airports, on planes and in crowded tourist spots, and outbreaks linked to travel have already appeared in some of the region's biggest hubs. If you're heading to East Asia or the Pacific islands, it's worth checking your vaccination record — adults who never had two doses of a measles-containing vaccine, or who are unsure of their status, can be vaccinated before departure. Babies travelling early, and anyone visiting areas with thinner health systems, should take the same advice extra seriously. A quick pre-trip check-up is far easier than dealing with an illness that can scuttle a holiday and spread onward when you fly home.