How should I manage a measles infection in an unvaccinated infant younger than 12 months?

Management of Measles in Unvaccinated Infants Under 12 Months

For an infant under 12 months with active measles infection, provide supportive care with close monitoring for complications, ensure immediate isolation for at least 4 days after rash onset, and administer vitamin A supplementation to reduce morbidity and mortality. 1, 2

Immediate Isolation and Infection Control

• Isolate the infant immediately and maintain isolation for at least 4 days after rash onset, as measles patients are contagious from 4 days before rash to 4 days after rash appears 1, 3
• Keep the infant out of daycare or any group settings during this entire contagious period 3
• Implement droplet precautions if the infant requires hospitalization 3

Supportive Care and Monitoring

• Treatment is primarily supportive, as there is no specific antiviral therapy for measles 3, 4
• Provide acetaminophen or NSAIDs for fever control and comfort 5
• Ensure adequate hydration and nutritional support 4
• Monitor closely for complications, which occur in 10-40% of measles cases and include pneumonia (the most common cause of death), diarrhea, otitis media, and encephalitis (1 per 1,000 cases) 3, 4

Vitamin A Supplementation

• Administer vitamin A supplementation, which is critical for reducing morbidity and mortality in children with measles, particularly in infants under 12 months who are at highest risk for severe disease 3

Post-Infection Vaccination Planning

• Once the infant recovers and reaches 12 months of age, administer the first dose of MMR vaccine at 12-15 months, followed by a second dose at 4-6 years 1
• Natural measles infection provides lifelong immunity, but vaccination should still be given to ensure protection against all three diseases in MMR 1

Management of Household Contacts

• Immediately identify all household contacts and assess their measles immunity status 1, 3
• For susceptible contacts aged ≥6 months: administer MMR vaccine within 72 hours of initial exposure 2, 3
• For infants under 6 months who are household contacts: administer immune globulin (IG) at 0.25 mL/kg IM (maximum 15 mL) within 6 days of exposure 1, 2
• For contacts who cannot receive MMR or were not vaccinated within 72 hours: administer IG within 6 days of exposure 3

Critical Pitfalls to Avoid

• Do not use acyclovir or other antivirals, as measles is caused by a paramyxovirus, not a herpesvirus, and these agents have no role in measles treatment 2
• Do not delay isolation while awaiting laboratory confirmation, as one confirmed case of measles constitutes an urgent public health situation requiring immediate action 1, 3
• Do not assume maternal antibody protection in infants under 6 months, especially if the mother herself had measles or if the infant shows symptoms 2
• Report the case immediately to local or state health departments, as measles is a notifiable disease and prompt public health response is essential to prevent further transmission 1, 3

Special Considerations for Infants Under 12 Months

• Infants under 12 months are at highest risk for severe complications and mortality from measles, with disease often being more severe in this age group 1, 2
• Pneumonia is the most common cause of death and requires aggressive respiratory support if it develops 3
• Bacterial superinfections should be treated promptly with appropriate antibiotics 3, 4