Quick answer
What is measles?
Measles is a highly contagious viral illness causing fever, cough, red eyes, and a distinctive red-brown rash that spreads from face downward. Most common in unvaccinated children but can affect adults severely. MMR vaccine provides excellent protection — two doses in childhood. Complications include pneumonia and encephalitis — rare but serious. Phone GP before visiting if suspected — isolate to protect others.
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
- 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).