For fun, AI was asked if measles evolves slower than flu? (both RNA virus)
Yes, the measles virus evolves slower than many other RNA viruses, like influenza. Measles, caused by a morbillivirus, has a relatively stable genome due to its high fidelity RNA polymerase and strong selective pressure to maintain its antigenic structure for human infection. Its mutation rate is estimated at around 0.9–1.1 × 10⁻⁴ substitutions per site per year, which is lower than influenza's rate of ~1–5 × 10⁻³. Influenza evolves faster due to antigenic drift and shift, driven by a more error-prone polymerase and broader host range, allowing rapid adaptation. Measles' slower evolution contributes to the long-term effectiveness of its vaccine.
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