Measles
Measles is an acute, highly contagious viral infection caused by a morbillivirus (Paramyxoviridae). It is important in emergency medicine because a single case can seed rapid transmission, the disease may cause severe complications, and confirmed or suspected cases trigger immediate public‑health action (notification, testing and contact‑tracing) (UKHSA).
Epidemiology and public‑health context
- Incubation period: typically ~10 days (range 7-21 days).
- Infectious period: from about 4 days before to 4 days after rash onset (UKHSA).
- Transmission: respiratory droplets and airborne particles; very high secondary attack rate in susceptible populations.
- Immunity: natural infection usually confers long‑lasting immunity; two doses of MMR give optimal vaccine protection.
- Notification: measles is notifiable; contact the local Health Protection Team (HPT/UKHSA) immediately for any suspected case (UKHSA, RCEM).
Who is at higher risk of severe disease
- Infants.
- Adults (including pregnant women).
- Immunocompromised people.
- Malnourished children.
- People with significant chronic disease.
Measles in pregnancy increases risk of miscarriage, stillbirth and maternal complications (UKHSA).
Clinical features
- Prodrome (2-4 days): high fever (often ≥39°C), malaise, cough, coryza and conjunctivitis.