In 2023, over 800 measles cases have been reported in the U.S., primarily in West Texas, with most cases occurring among unvaccinated individuals, though 3% are breakthrough infections in vaccinated people. Despite claims on social media, the MMR vaccine is highly effective, providing 93% protection after one dose and 97% after two; breakthrough cases are typically milder and less contagious. Experts assert that vaccine-induced immunity is generally long-lasting, contradicting claims of rapid waning, and emphasize that rare breakthrough infections can result from various factors, including incomplete vaccination and individual immune responses.
