PEDI | Measles (rubeola)

Measles (rubeola) is an acute, highly contagious viral respiratory illness characterized by a distinct prodrome of fever and the "three Cs" (cough, coryza, and conjunctivitis), followed by a generalized rash. While indigenous transmission was declared eliminated in the U.S. in 2000, outbreaks continue to occur due to importation and unvaccinated populations.Clinical Presentation and Transmission• High Infectivity: The virus spreads via respiratory droplets and can remain airborne in closed areas for up to 2 hours. It is highly communicable, with a secondary attack rate of over 90% among susceptible contacts.• Contagious Period: Patients are contagious from 4 days before until 4 days after the rash appears.• Symptom Timeline: ◦ Incubation: Symptoms typically begin 7 to 14 days after exposure. ◦ Prodrome: Characterized by a stepwise fever rising to 103°F–105°F, cough, runny nose, and pink eye. ◦ Koplik Spots: Small blue-white spots on the inner cheek appear 1–2 days before the rash; these are considered unique to measles. ◦ Rash: A deep red, maculopapular rash begins at the hairline and spreads downward to the neck, torso, and extremities over 3 days.• Complications: Common complications include ear infections and diarrhea, while severe outcomes include pneumonia, encephalitis (brain inflammation), and death.Vaccination Protocols (MMR and MMRV)Prevention relies on the live, attenuated MMR (measles, mumps, rubella) or MMRV (+ varicella) vaccines.• Standard Schedule: Two doses are recommended for children: 1. Dose 1: Age 12 through 15 months. 2. Dose 2: Age 4 through 6 years (before school entry).• Efficacy: A single dose produces immunity in ~95% of children, while two doses provide >99% immunity, which is expected to be lifelong.• MMRV Precautions: For the first dose in children aged 12–47 months, administering separate MMR and Varicella vaccines is preferred over the combined MMRV shot, as MMRV carries a twofold higher risk of febrile seizures in this specific age group.• Adults and Travelers: Adults without evidence of immunity and international travelers (including infants 6–11 months) require vaccination, as measles remains endemic globally.Safety and Contraindications• Contraindications: Because it is a live vaccine, it must not be administered to pregnant women or individuals with severe immunocompromise (e.g., untreated HIV, leukemia, or high-dose steroid therapy).• Adverse Events: Common side effects include fever (5–15%) and a transient rash (5%) occurring 7–12 days post-vaccination.• Autism: Extensive studies and reviews by the National Academy of Medicine have refuted a causal relationship between the MMR vaccine and autism