Increasing measles cases in the Western Pacific Region

In the Western Pacific Region, measles cases increased by 259% between 2022 and 2023¹ (Figure 1). This is likely to be a combined result of decline in measles vaccinations during the COVID-19 pandemic and increased population movements and disease surveillance activities post-pandemic.

During COVID-19 pandemic, vaccination coverage of first dose of measles-containing vaccine (MCV1) decreased from 95% in 2020 to 91% in 2021 (Figure 2). While MCV1 coverage increased slightly to 93% in 2022 but it is yet to recover the pre-pandemic level of 95%. When measles is imported into communities where vaccination coverage is below 95%, people in those communities are vulnerable to measles outbreaks due to insufficient herd immunity. During 2020-2022, 3.6 million children in the Region missed their routine vaccination against measles.

Measles is one of the most infectious diseases on earth, spreading easily when an infected person breathes, coughs or sneezes. A single person infected with measles can potentially spread the disease to 9 out of 10 unvaccinated people, which can lead to severe complications and deaths in some cases.

Countries and areas in the Western Pacific are working hard to close the immunity gaps. From 2022 to 2023, 11 countries − Fiji, Kiribati, Marshall Islands, the Federated States of Micronesia, Mongolia, Palau, Papua New Guinea, the Philippines, Samoa, Solomon Islands and Viet Nam − conducted measles and rubella mass vaccination campaigns or catch-up vaccination activities. Cambodia and the Lao People’s Democratic Republic are planning nationwide measles and rubella vaccination campaigns in 2024. Countries are also intensifying surveillance of vaccine-preventable and other infectious diseases to rapidly detect suspected cases to promptly confirm, respond to, and control outbreaks.

Vaccination is one of the most cost-effective public health interventions and one of the best health interventions money can buy. As the world celebrates the 50th anniversary of Expanded Programme on Immunization, the global immunization community continues its efforts toward a world where everyone, everywhere, at every age, fully benefits from vaccines to improve health and well-being.

Related links:

• Western Pacific countries at risk of measles outbreak due to immunization and surveillance gaps
• Eliminating measles and rubella