Measles — not a harmless childhood rash
Measles is one of the most contagious human diseases — a single case can infect 9 out of 10 unvaccinated people in close contact. Before vaccination, it killed millions globally; MMR vaccine reduced UK cases dramatically — but outbreaks resurge where vaccination rates fall.
It is not trivial — 1 in 15 affected children in the UK develop serious complications.
Symptoms — typical timeline
Day 1 to 3 — prodrome:
- high fever (often 40°C+)
- runny nose, cough
- red, watery eyes (conjunctivitis)
- general malaise
Koplik spots — tiny white/grey spots on buccal mucosa (inside cheeks) — pathognomonic, fade as rash appears.
Day 3 to 7 — rash:
- red-brown maculopapular rash
- starts behind ears and hairline, spreads face → chest → limbs
- blanches on pressure (unlike meningococcal rash)
- fades in order of appearance over 5 to 6 days — may brownish desquamation
How it spreads
Respiratory droplets — cough, sneeze, breathing shared air.
Virus survives in airspace up to 2 hours after infected person leaves room.
Incubation: 10 to 12 days to first symptoms; 14 days to rash.
Who is at risk
- unvaccinated children and adults
- infants too young for vaccine (<12 months)
- immunocompromised — cannot receive live vaccine; rely on herd immunity
- pregnant women without immunity — miscarriage, prematurity, low birth weight risk
MMR vaccination
Schedule UK:
- 1 year — MMR dose 1
- 3 years 4 months — MMR dose 2
Catch-up: anyone missing doses — GP practice or sexual health for adults.
Contraindications to live MMR:
- pregnancy — avoid pregnancy 1 month after
- severe immunosuppression
- anaphylaxis to neomycin or gelatine (rare)
Treatment — supportive
- paracetamol/ibuprofen — fever, discomfort
- fluids — prevent dehydration
- rest
- no school/work — isolation period
- vitamin A — WHO recommendation in severe measles in deficiency settings — hospital
Antibiotics — only for secondary bacterial infection.
Complications
| Complication | Notes |
|---|---|
| Otitis media | Common |
| Pneumonia | Leading cause of measles death |
| Diarrhoea | Dehydration risk |
| Encephalitis | 1 in 1000 — brain injury/death |
| SSPE | Years later — fatal — very rare |
Measles vs other rashes
| Measles | Scarlet fever | Meningitis | |
|---|---|---|---|
| Rash | Head down, blanching | Sandpaper, scarlet | Non-blanching petechiae |
| Prodrome | Cough, conjunctivitis | Sore throat | Rapid collapse possible |
See scarlet fever guide.
Public health
Notify — measles is notifiable — labs and clinicians report cases.
Contact tracing — unvaccinated contacts may receive MMR within 72 hours post-exposure or immunoglobulin if vulnerable.
Phone ahead before GP visit — do not sit in waiting room with measles.
Measles is almost entirely preventable with two MMR doses — resurgence reflects vaccine gaps, not virus weakening. If unvaccinated — catch up today.
Common questions about measles
- What are the first signs of measles?
- High fever, runny nose, cough, red sore eyes (conjunctivitis), and small grey-white Koplik spots on inside of cheeks — rash follows 2 to 4 days later starting on face and spreading downward over 3 to 4 days.
- How long is measles contagious?
- From 4 days before rash appears until 4 days after rash onset — roughly 8 days total. Stay home from school, work, and public places during this period. Highly contagious to unvaccinated people in same room.
- Can adults get measles?
- Yes — often more severe than children — higher hospitalisation and complication rates. Adults born before 1970 may have natural immunity; those without two MMR doses or confirmed immunity should vaccinate if not pregnant or immunosuppressed.
- Is there a treatment for measles?
- No specific antiviral — supportive care with paracetamol or ibuprofen, fluids, rest. Vitamin A given in some severe cases in hospital — deficiency worsens outcomes. Antibiotics only if bacterial complication like pneumonia develops.
- How effective is the MMR vaccine?
- One dose protects about 93% — two doses about 97%. MMR also covers mumps and rubella. Safe for most people — myths linking MMR to autism disproved repeatedly by large studies.
- What complications can measles cause?
- Ear infection, pneumonia, diarrhoea, fits (febrile convulsions), encephalitis (brain inflammation — rare, can be fatal or cause brain damage), subacute sclerosing panencephalitis (very rare late complication years later).
Sources
How we reviewed this page
Medically reviewed by the HealthAnswers UK doctor review panel
- First published
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- or sooner if NHS or NICE guidance changes
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