What should I do if I suspect measles?

Suspected measles: exactly what to do now

Isolate immediately, mask (N95) the patient and staff, report to public health the same day, and collect measles labs (IgM plus PCR/viral isolation) without delaying control measures. 1

• Immediate infection control (protect morbidity/mortality/QoL)

  • Put patient in airborne isolation (AIIR if available); both patient and staff use N95s. Minimize movement. 2, 3
  • Triage “vital sign zero”: isolate before vitals to prevent transmission. 4

• Notify public health now

  • Same-day phone report to local/state health department; one confirmed case is an urgent public health event. Do not wait for labs to start control. 1

• Test correctly (don’t delay control)

  • Draw serum for measles IgM at first encounter; if drawn within 72 hours of rash and negative, repeat ≥72 hours after rash onset. 1
  • Collect a second specimen for virus detection/genotyping ASAP (nasopharyngeal/throat swab or urine) in coordination with public health. PCR/isolation supports confirmation and outbreak tracing. 1
  • If measles serology is negative in a febrile rash illness, test for rubella to avoid missed diagnoses. Beware false-positive measles IgM (e.g., parvovirus) when incidence is low; use high-specificity assays via public health labs. 1

• Clinical case fit (to prioritize who you isolate/test first)

  • Fever ≥38.3°C, generalized maculopapular rash ≥3 days, plus cough/coryza/conjunctivitis. Consider exposure/travel and infectious window: ~4 days before to 4 days after rash onset. High-risk: infants, pregnant, immunocompromised. 1, 2, 3

• Post-exposure actions (within 72 h for vaccine; within 6 days for IG)

  • Identify exposed contacts with public health; vaccinate susceptible contacts promptly; exclude those lacking evidence of immunity from schools/healthcare settings during outbreaks per health department. 1
  • Infants <12 months with household exposure: prefer immune globulin (IG); do not use IG to control community outbreaks. 1
  • Healthcare/childcare/school outbreaks: revaccinate attendees/staff without 2 documented doses or other proof of immunity; exclude non-immune persons until 21 days after last case’s rash onset. 1

• Treatment and disposition

  • Supportive care; give vitamin A in severe pediatric cases as advised locally; escalate care for high-risk (pregnant, immunocompromised, very young) and for complications (pneumonia/CNS). 2, 3, 5

• Common pitfalls to avoid

  • Waiting for labs before isolating/notifying public health. Start control immediately. 1
  • Single early negative IgM: repeat after 72 hours post-rash if suspicion remains. 1
  • Missing infection control for “pre-rash” presentations—patients are infectious before rash. 3
  • Relying on low-specificity IgM assays without confirmatory testing via public health labs. 1

• Prevention after this episode (to reduce future morbidity/mortality/QoL loss)

  • Ensure 2 documented MMR doses for all eligible persons; vaccinate at 12–15 months and again before school entry; consider early dose (6–11 months) during outbreaks/travel with revaccination on schedule. 1