Measles at a Glance
Measles is a highly contagious viral illness caused by measles virus (genus Morbillivirus). It begins with a prodrome of fever, cough, coryza (runny nose), and conjunctivitis, followed by the classic maculopapular rash. Koplik spots (tiny white lesions on the buccal mucosa) are characteristic in the prodromal phase.
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Key Clinical Features
- Prodrome (3–4 days): high fever, cough, coryza, conjunctivitis; Koplik spots on the buccal mucosa.
- Rash: starts on the face and behind the ears, spreads downward to trunk and limbs; lesions may become confluent; fades in the same order.
- Infectious period: from about 4 days before to 4 days after rash onset (immunocompromised patients may shed longer).
How Measles Spreads
- Reservoir: humans only.
- Route: airborne transmission via fine respiratory particles/aerosols; virus can remain infectious in the air and on surfaces for up to ~2 hours.
- Contagiousness: very high (most susceptible contacts become infected without immunity). Outbreaks are fueled in undervaccinated settings.
Complications
- Otitis media, laryngotracheobronchitis (croup), pneumonia (a leading cause of death), diarrhea/dehydration.
- Acute encephalitis and post‑infectious encephalomyelitis; rare, late complication: subacute sclerosing panencephalitis (SSPE).
- Higher risk of severe disease in infants, pregnant people, the immunocompromised, and those with vitamin A deficiency or malnutrition.
Prevention — Vaccination Works
- Vaccine: MMR (measles‑mumps‑rubella) or MMRV (includes varicella).
- Schedule (typical): first dose at 12–15 months; second dose at 4–6 years. Unvaccinated children and adults should receive catch‑up vaccination per local guidelines.
- Effectiveness: two doses provide ~97% protection against measles.
- Travelers, students, and healthcare workers should ensure documented immunity (two doses or laboratory evidence).
Post‑Exposure Prophylaxis (PEP)
- MMR vaccine within 72 hours of exposure can prevent or modify illness in susceptible people without contraindications.
- Immune globulin (IG) within 6 days of exposure for high‑risk susceptible contacts (e.g., infants <12 months, pregnant people without evidence of immunity, severely immunocompromised). Dosing and product (IMIG vs IVIG) vary by local guidance.
- Exclude susceptible contacts without timely PEP from high‑risk settings for the recommended period (often 21 days after last exposure).
Isolation and Infection Control
- Suspected or confirmed cases should isolate with airborne precautions. In healthcare settings, use an airborne infection isolation room and respirators.
- Community isolation typically continues until 4 full days after rash onset (longer may be needed for the immunocompromised; follow public health advice).
Diagnosis and Reporting
- Confirm with laboratory testing when possible: RT‑PCR/NAAT from respiratory specimens and measles‑specific IgM serology.
- Measles is a notifiable disease — promptly notify public health authorities to support contact tracing and outbreak control.
Care
- Supportive management: fluids, antipyretics, and monitoring for complications; treat bacterial coinfections when present.
- Vitamin A supplementation is recommended for hospitalized children or those at risk of deficiency per local/national guidelines.
Takeaways
- Measles is airborne and extraordinarily contagious; vaccination is the best protection.
- Early recognition, isolation, and timely PEP limit spread and protect vulnerable people.
Educational information only; follow local public health guidance and consult a clinician for individual care.