As part of our Vaccine Engagement Day campaign, we are sharing a series of blogs exploring vaccines, from major public health successes to future innovations. In this second blog, we explore the introduction of the MMRV vaccine and why it represents an important step in how vaccination programmes continue to evolve.
Vaccines are one of modern medicine’s greatest achievements. It’s estimated they have saved over 154 million lives over the last 50 years, the equivalent of 6 lives every minute. Previously common illnesses, particularly in children, are now far less of a threat in many parts of the world. We are routinely protected against twenty different diseases in the UK, and vaccination programmes are constantly evolving to offer the best protection to as many people as possible.
Each vaccine is carefully assessed to make sure it is needed, safe and offered at the right time. In the UK, it's the job of the Joint Committee on Vaccinations and Immunisation (JCVI) to review the latest evidence and makes recommendations on the vaccination schedule. This includes decisions on when vaccines should be given, whether booster doses are required, and when new vaccines should be introduced.
From 1 January 2026, the JCVI decided to move from offering the MMR (measles, mumps rubella) vaccine to the MMRV vaccine, that includes chickenpox (varicella). The change means that children are protected against 4 serious, and quite contagious, illnesses all in a single combined vaccine.
How combination vaccines improved uptake
Vaccines for measles, mumps and rubella were previously given separately in the 1960s and 1970s, and whilst this was effective, it meant more appointments, and subsequently the uptake was disappointingly low.
The introduction of the combined MMR vaccine in 1988 marked an important step forward. By protecting against three diseases in one vaccine, it simplified the process for families and led to the uptake exceeding 90% in the UK. It also meant that young children had protection against these serious illnesses sooner, rather than having to spread out the vaccinations into different appointments.
For many families, attending vaccination appointments can be challenging. Young children may feel anxious about injections, and multiple appointments can add to the stress for both children and parents. By reducing the number of injections and visits needed, combination vaccines can make the experience simpler and less stressful.
As uptake increased after the introduction of the combined MMR vaccine, cases of measles, mumps and rubella fell significantly, showing how making vaccination simpler can lead to better protection for more people. Image A (taken from Gavi, The Vaccine Alliance) illustrates this trend, showing the relationship between measles cases and vaccination coverage over time. It is hoped that the recent move to the MMRV vaccine will follow this same approach.
How effective is the MMRV vaccine?
The MMRV vaccine has been used in other countries for over a decade, including in Germany, Canada and the USA. It has been shown that two doses of the MMRV vaccine are incredibly effective at preventing serious illness. The vaccine is:
- 96% effective against measles
- 86% effective against mumps
- 89% effective against rubella
- 97% effective against varicella
What are measles, mumps, rubella and varicella, and why is vaccination so important?
All four diseases are very contagious. One person with measles can infect up to 18 other unvaccinated people, and they can have dangerous complications. They start with symptoms common to many illnesses like a high temperature, a cough and a runny nose. As they progress however, their distinctive symptoms emerge.
Measles can cause white spots in the mouth, known as Koplik spots, and then a rash typically starting on the face that then spreads across the body. Mumps can cause swelling of the cheeks and neck that is often nicknamed ‘hamster cheeks’ making it harder to chew, swallow and speak. Rubella causes a similar rash to measles, spreading from the head downwards and usually lasting around 3 days. Chickenpox (varicella), meanwhile, is characterised by spots across the whole body – you can find out more about chickenpox and the varicella zoster virus that causes it in our first blog of this series.
Although many people recover without becoming seriously ill, these infections can be very dangerous for some people. Measles can cause pneumonia, swelling of the brain (encephalitis), and in some cases long-term complications or even death. Chickenpox can also lead to complications including pneumonia and encephalitis. Mumps can cause infertility in boys and men that have gone through puberty, and rubella infection during the first 20 weeks of pregnancy can cause a miscarriage or lifelong disabilities for the unborn baby. The risk of these serious complications highlights why vaccination is so important, helping to prevent severe illness and protect those most vulnerable.
In recent years, researchers have identified that measles can have another, unexpected, effect on your immune system called ‘immune amnesia’. As we get illnesses and fight them off or have a vaccination, our body builds up a memory of how to fight off that illness again in the future. So, the next time we encounter that illness our body ‘remembers’ what to do and we are much less ill, if we get ill at all. Becoming infected with measles can cause the body to forget all these memories of past illnesses. This means that even if you’ve fought off an illness before, the memory of what to do doesn’t exist anymore and your body has to learn how to fight it off all over again leading to you becoming more sick more often.
Getting the MMRV vaccine
Getting your child vaccinated is one of the most important things you can do to keep them healthy, and help to protect others at the same time.
The rollout of the MMRV vaccine is taking place in stages, depending on when your child was born:
- If they were born on or after 1 January 2025: doses at 12 and 18 months as part of their normal appointments
- If they were born on or before 31 December 2024: eligibility depends on exact birth date – you can find out what vaccines they are eligible for on the NHS
You will be contacted by your GP when it is time for vaccinations, but it is never too late to get vaccinated, if you are unsure if you or your child has missed vaccinations for whatever reason, get in touch with your GP and they will be able to offer advice.
You can also find out more about childhood vaccinations, how they work and answers to common questions in our guide to vaccinations during childhood.
By Chris Snowden-Smith, Careers and Engagement Officer