Measles outbreak in US puts global vaccination campaigns at risk

A third US measles outbreak this year has put global health officials on alert and triggered a warning to those planning travel to affected states.

The virus was officially eliminated from the US in 2000 but cases brought into the country from overseas have since has led to a rise in infections. Last year, 285 cases of measles were recorded but less than three months into this year, 378 infections had already been confirmed by March 20.

In a nation of 347 million people, those numbers might appear insignificant but still represent a major increase in 12 months, from the 107 cases in the first three months of 2024.

Eliminating measles from the US was marked as a historic public health achievement. That work is now under threat from rising vaccine hesitancy and social media misinformation.

Vaccine coverage rates vary significantly between US states but a total of 18 jurisdictions nationwide reported incidents of measles by March this year.

“Since the start of the year, we’ve seen a sharp rise in measles cases reported in the US, with two deaths so far – many of these cases are in Texas,” said Janeen Madan Keller, deputy director of Global Health Policy Programme at the Centre for Global Development, told The National.

“Across the US, the coverage rate of the measles, mumps and rubella [MMR] vaccine among kindergarteners has been declining in recent years. It is now below the target coverage rate of 95 per cent, with significant variation across communities.”

Plunging vaccination coverage

Falling US immunisation rates could have far-reaching effects on the rest of the world, Ms Madan Keller said.

“First, this could influence public perception on vaccines, extending far beyond the US,” she added. “Second, as we’ve learnt, an infectious disease outbreak quickly travels across international borders. As measles vaccination rates decline in the US, there is a higher chance of outbreaks linked to travel.”

The MMR vaccine, proven to be safe, has been circulated widely since the early 1970s, preventing millions of infections around the world. Symptoms of the virus include a cough, fever and blotchy skin rash. In severe cases, measles can lead to pneumonia and encephalitis, a brain infection.

When more than 95 per cent of a population is vaccinated, most people are protected through herd immunity. But when those rates begin to decline, infections begin to creep up. In the US, vaccination among preschool-aged children slipped from 95.2 per cent in the 2019-20 school year to 92.7 per cent in 2023-24.

Outbreaks are defined as three or more related cases. So far in 2025, there have been three outbreaks in the US, with younger people the most vulnerable.

This year, 17 per cent of US cases have been resulted in hospital stays, with 42 per cent of those with measles aged five-19, and 33 per cent under five.

A resurgence of measles after aggressive global anti-vaccine campaigns prompted the World Health Organisation (WHO) to name vaccine hesitancy as one of the greatest global health threats. Political persuasion can also affect effective immunisation campaigns.

Funding cuts

Since President Donald Trump took office for a second term, he has pulled the US out of the WHO and stopped funding for Gavi, the Vaccine Alliance – a global health partnership that aims to increase immunisation in developing nations. Previously, the US provided about 13 per cent of Gavi's funding.

Natasha Crowcroft, a senior technical adviser on measles and rubella at the WHO, said funding cuts could affect global action to limit the spread of new infections.

“The US withdrawal [from the WHO] is having a major impact on the ability to support global measles and rubella elimination efforts,” she said. “The US funds the entire measles prevention system at global and regional levels, and much of the support that can be provided to countries in need.

“This includes funding for leadership and expertise, vaccination programmes, tracking of measles cases, response to outbreaks and the entire global measles and rubella laboratory network of more than 760 labs around the world.”

US funding has helped support measles elimination in 40 per cent of the world’s countries, Ms Crowcroft said, which helped keep a lid on further infections. Measles anywhere in the world is a risk where immunisation coverage is below 95 per cent.

Currently, the global coverage rate of the first dose of the measles vaccine is 83 per cent and the second dose is 74 per cent, contributing to outbreaks worldwide. In total, about one in four children are not fully vaccinated against measles.

In 2025, a number of global campaigns are planned to reach unimmunised children with measles vaccines in Democratic Republic of the Congo, Nigeria, Ethiopia and Pakistan.

“The reduction of WHO support threatens the quality of those campaigns, increasing the risk they are delayed or don’t reach all children at risk,” said Ms Crowcroft. “We anticipate seeing increasing cases, outbreaks and deaths from measles as a result.”

In the UAE, a campaign partnership between Emirates Health Services, Abu Dhabi Public Health Centre and Dubai Health Authority was launched in November to boost vaccination rates and support a global goal of eliminating the disease by 2030.

Dr Mamata Bothra, specialist paediatrician and neonatologist at International Modern Hospital in Dubai, said anyone travelling to the US should plan accordingly.

“Measles is not a simple infection and can be fatal,” she said. “After Covid, there was a break in vaccinations of some children. Since then, some parents no longer consider vaccination as that important. We are seeing many unvaccinated patients, not because the government facilities or health facilities are not giving them, but because parents are not taking them seriously.

“When we have large numbers of patients unvaccinated, the risk of measles rises. Anybody travelling to the US should check to see their child is fully vaccinated [against measles]. You should not go to crowded places when you hear there's an outbreak, and if your child is having fever and rash, immediately see a doctor.”

Social media impact

Research by Columbia University's Mailman School of Public Health found social media has contributed to misinformation around vaccines and their effectiveness.

Results published in the British Medical Journal found misinformation surrounding a number of vaccines, including childhood inoculations, HPV, Covid-19 and flu. Researchers at the university said simply banning misinformation on social media could backfire by driving people towards even less accurate sources of information.

Efforts at debunking were also found to have had mixed results. While countering misinformation, they have the potential to deepen false beliefs. Effective messaging should include addressing reasons for hesitancy, while reinforcing cultural values, such as free choice and family protection, while building on trust, researchers say.

“Social media platforms are the epicentre of misinformation – they also need to be part of the solution,” said Kai Ruggeri, study author and professor of health policy and management at Columbia's Mailman School.

“Misinformation is not new and its noxious consequences are not insurmountable, but its effect on vaccine hesitancy through social media is an urgent global threat to public health.”