How the MMRV protects against 4 potentially serious illnesses, including chickenpox

摘要

Comprehensive guide to the MMRV vaccine which replaced MMR in the routine childhood program from 1 January 2026, now protecting against four diseases including chickenpox.

詳細內容

This blog post was last checked and updated January 2026. Due to the introduction of a varicella (chickenpox) vaccination programme, the measles, mumps, rubella and varicella (MMRV) vaccine replaced the MMR vaccine in the routine childhood programme from 1 January 2026.

What is MMRV vaccine?

Measles
Mumps
Rubella (German measles)
Varicella (chickenpox)

A combined vaccine protecting against four potentially serious viral diseases with a single injection.

The four diseases:

1. Measles:

Highly contagious viral disease
Causes fever, cough, rash
Complications: Pneumonia, encephalitis, death
2024 saw 2,911 cases in England - highest in decades

2. Mumps:

Viral infection causing swollen glands
Can cause meningitis, encephalitis
Rarely causes deafness or infertility
Outbreaks still occur in under-vaccinated populations

3. Rubella (German measles):

Usually mild in children
Serious risk in pregnancy: Can cause congenital rubella syndrome (deafness, blindness, heart defects in unborn baby)
Vaccinating children protects pregnant women through herd immunity

4. Varicella (Chickenpox) - NEW:

Very contagious, causes itchy rash and blisters
Usually mild but can have serious complications
Complications: Secondary bacterial infections, pneumonia, encephalitis
Higher risk in infants, adults, immunocompromised
Can cause shingles later in life

MMRV schedule:

First dose: 12 months old
Second dose: 3 years 4 months old
Two doses: Provides optimal protection against all four diseases
Free: Provided by NHS at no cost

Who is eligible?

Routine program (from 1 January 2026):

All children reaching 12 months on or after 1 January 2026
All children due for preschool booster (3 years 4 months) on or after 1 January 2026

What about children born before 2026?

Children already vaccinated with MMR: May be offered catch-up varicella vaccination separately
Specific eligibility depends on age and previous vaccination status
Parents should check with GP practice

Effectiveness: After two doses:

Measles: 99% protection
Mumps: 88% protection
Rubella: 99% protection
Varicella: 95% protection (significantly reduces severe disease even when breakthrough occurs)

Safety:

Extensively tested before introduction
Used successfully in other countries (USA, Australia, Germany)
Similar side effects to MMR:
- Common: Mild fever, redness/swelling at injection site
- Less common: Mild rash (measles-like or chickenpox-like)
- Rare: Febrile seizure (usually harmless)
Benefits far outweigh very small risks

Why combined vaccine?

Fewer injections for children
Better compliance (all protection in one visit)
Proven safety of combination
Cost-effective for NHS
Successful model used for decades with other combined vaccines

Chickenpox vaccination rationale: Adding varicella to routine schedule because:

Annual burden: ~500,000 chickenpox cases in UK
Hospitalizations: Hundreds annually, including deaths
Complications: Serious bacterial infections (Group A Strep), pneumonia, encephalitis
Vulnerable populations: Immunocompromised children at severe risk
Shingles prevention: May reduce future shingles burden
Economic impact: School absence, parental work loss

Common questions:

“Won’t natural chickenpox give better immunity?”

Vaccine provides excellent immunity without the risks of natural infection
Natural infection can cause serious complications
Vaccination safer than disease

“Will this cause more shingles in adults?”

Research suggests no - may actually reduce shingles
Shingles vaccine available for older adults

“What if my child already had chickenpox?”

One dose may still be offered (provides boost)
Discuss with healthcare provider
No harm if vaccinated after natural infection

“Can siblings catch vaccine virus?”

Very rare mild rash possible after vaccination
Any rash should be covered
Risk extremely low compared to natural infection

Important message: The MMRV vaccine represents an important advancement in childhood disease prevention. By protecting against four serious diseases with excellent safety and effectiveness, it gives children the best possible start in life. Parents should ensure their children receive both doses on schedule. Those with questions should speak to their GP practice or health visitor.

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