On Thursday 18 , a committee of the US Centers for Disease Control and Prevention (CDC) voted to recommend that children should receive multiple separate vaccines to protect against measles, mumps, rubella and chickenpox.
This recommendation replaces the current policy in the US of children receiving a single vaccine, MMRV, to cover them against all four diseases.
The decision by the advisory committee on immunization practices (ACIP) has alarmed experts at the London School of Hygiene & Tropical Medicine (LSHTM) who say that the move goes against decades of scientific consensus on the best approach to childhood vaccination, could confuse parents and lead to children missing vital vaccinations.
It comes in the context of lethal outbreaks of measles occurring in countries including the US and the UK, and worries over a failure to reach the WHO target of 95% of people being fully-vaccinated with two doses of the MMR vaccine. In 2024, 85% of people in the UK received two doses of MMR, well below this target.
Dr. Ben Kasstan-Dabush, Assistant Professor at LSHTM, said, “There were close to 3,000 laboratory confirmed cases of measles in England in 2024, outbreaks continued into 2025 and led to the death of a child. Similar patterns have occurred in the US, with two child deaths linked to measles in 2025. The deaths and most cases of sickness in the UK and US were in unvaccinated children, reminding us that the MMR vaccine has been given to generations of children for over 40 years because of its record of safety and effectiveness.
“The decision by the US vaccine committee appears to be less about reviewing evidence than re-envisioning evidence. Consensus on evidence is critical for health care practitioners to recommend vaccines and for parents to feel confident that those recommendations are in place to protect their children.
“While bodies such as the West Coast Health Alliance are moving to offer evidence-based recommendations and push back against Kennedy’s actions, I worry about those parents trying to make sense of diverging public health recommendations at state and federal levels.
“Countries usually vary in the immunization schedules that they offer parents, and variation in itself is not a problem for parents in the UK. The issue in this case is the potential to disorient public opinion.
“From 2026, the NHS routine immunization schedule will change and parents will be offered the second dose of MMR at 18 months instead of 3 years and four months, and a varicella (chickenpox) component will be added. Communities with low uptake of MMR vaccination must be prepared ahead of the schedule change, particularly diaspora communities with transnational links to the US due to the international flows of misinformation.
“I am deeply concerned about the ability to work with communities, by co-producing communications with community partners, when NHS Integrated Care Boards are expected to slash their operational costs by as much as 50%.”
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