It’s 8:00 a.m. in Russey Keo district, on the outskirts of Phnom Penh. Children sit in rows of plastic chairs, fidgeting as they wait for their turn to be vaccinated. Parents stand nearby, vaccination cards in hand. Some reassure their children; others simply watch.
Among them is Phanna, a night-shift factory worker waiting with his daughter. “I got vaccinated when I was young, but I didn’t really know what diseases I was protected from,” he said.
When asked about measles, Phanna smiled and admitted he wasn’t sure what it was or how dangerous it could be. He just knew that getting his daughter vaccinated felt like the responsible thing to do.
Like Phanna, many families lining up for vaccines are unaware of the urgency behind the situation: a measles outbreak has been quietly spreading across Cambodia.
The on-going measles outbreak
From January to April 2025, Cambodia reported 2,150 measles confirmed cases. This is a sharp increase compared to the 666 cases reported in all of 2024.
The current outbreak has affected all 25 provinces, with Phnom Penh the hardest hit, reporting 394 cases, followed by Siem Reap with 208 and Kandal with 167. The surge is particularly alarming given the heightened risk to children who are unvaccinated or under-immunized.
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Children sit waiting for vaccinations | Photo credit: © WHO / Enric Catala
Measles is one of the most contagious viral diseases, most common among children. It typically begins with a high fever, cough, and runny nose, followed by a distinctive full-body rash. While it may seem mild at first, measles can lead to serious complications, including pneumonia, brain swelling, permanent disability, and even death. Yet it is entirely preventable—with one simple and effective tool: vaccination.
A rapid response
From May 12 to 19, the measles outbreak immunization response was rolled out across 103 operational districts in all 25 provinces. The outbreak response targeted children aged 6 months to 14 years.
Health workers were on the move, traveling to remote villages to administer vaccines. Commune councils, village leaders and village health support groups supported health workers on the vaccination at the post in the villages and went door to door, urging parents to bring their children for vaccination and helping ensure no child is left behind.
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Tem Sreyneth greets children and parents arriving for vaccinations | Photo Credit: © WHO / Enric Catala
Tem Sreyneth, a vaccinator at the Kilometre Number 6 Health Centre, was already on her third day of the immunization activity in the community. With more than a decade of experience at the health centre, she knows the challenges all too well. One of the biggest, she says, is misinformation.
“Some parents worry their children will get a fever after the vaccine,” she said. “I take the time to reassure them that mild side effects are normal. They go away in a few days, but the real danger is measles itself.”
In just a few hours, Sreyneth had already vaccinated around 50 children. She was happy to see so many parents turn up for the event. “I always tell parents they don’t have to decide right away. Just show up and bring the vaccination card. We are happy to check everything and walk you through the process.”
Dr Po Rithy, Deputy Director of Phnom Penh Municipal Health Department, adds that logistical barriers also prevent some parents from accessing vaccines.
“Some parents aren’t aware of the risks. Others don’t have the transport or means to reach health centers. And in other cases, children often miss follow-up doses or booster shots when parents relocate for work outside their hometown.” He notes that the campaign works when parents understand the importance of vaccination.
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Dr Po Rithy visits the outbreak immunization activity in Russey Keo district | Photo Credit: © WHO / Enric Catala
Beyond the border
Cambodia is not alone in facing the resurgence of measles. Since 2023, global measles cases have risen sharply, driven by declines in vaccination coverage during the COVID-19 pandemic and increased population mobility. The upward trend has continued into 2024, with significant spikes observed across the Western Pacific Region.
Ten years ago, in March 2015, Cambodia achieved measles-free status. The disease, once no longer seen as a threat, has reemerged as a serious public health concern.
The resurgence underscores the urgent need for sustained immunization efforts, targeted outreach to mobile and underserved populations, and stronger disease surveillance systems to prevent future outbreaks.
WHO works closely with the National Immunization Program of the Ministry of Health in Cambodia to strengthen surveillance, improve high immunization coverage, and support timely outbreak response efforts.