Can You Get Measles Again After Having It Once?
No, a person with a healthy immune system who has had measles once will not get measles again—natural measles infection induces lifelong immunity to reinfection. 1
Natural Immunity is Lifelong and Superior
- Natural measles infection provides lifelong protection against reinfection in immunocompetent individuals, which is more durable than vaccine-induced immunity 1
- The CDC explicitly states that persons with a history of physician-diagnosed measles have acceptable evidence of immunity and do not require vaccination 2
- In studies comparing natural infection to vaccination, only 6% of those with self-reported history of measles lacked detectable protective antibodies, compared to 20% of vaccinated individuals (p < 0.0001) 3
Mechanism of Lifelong Protection
- Natural measles infection stimulates higher antibody levels (GMT = 213.3) compared to vaccination (GMT = 92.2), providing more robust and sustained immunity 3
- While antibody levels from natural infection may decline over time, the immune memory remains intact and prevents clinical reinfection 1
- The CDC notes that asymptomatic measles reinfection can theoretically occur among persons who previously developed antibodies, but symptomatic reinfections are rare, and those resulting in detectable measles IgM antibody occur even more rarely 2
Important Caveat: Immunocompromised Patients
- This lifelong immunity applies only to persons with healthy immune systems 2
- Individuals who are immunocompromised due to immune deficiency diseases, leukemia, lymphoma, generalized malignancy, or immunosuppressive therapy may not maintain protective immunity even after natural infection 2
- HIV-infected persons and those on corticosteroids, alkylating drugs, antimetabolites, or radiation therapy should be evaluated individually for their immune status 2
Clinical Implications
- If a person with documented history of measles develops a measles-like illness, alternative diagnoses (rubella, parvovirus, other viral exanthems) should be strongly considered 2
- Laboratory confirmation with measles IgM testing can help distinguish true measles from other febrile rash illnesses, though false positives can occur with parvovirus infection 2
- No additional measles vaccination is needed for persons with documented physician-diagnosed measles, regardless of travel to endemic areas or outbreak exposure 2