Measles vaccines are safe and effective
Measles vaccination prevents a highly contagious disease that can cause serious illness and death. MMR is highly effective and does not cause autism. Vitamin A can support measles care, but it does not replace vaccination. Serious side effects are rare.
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Vaccination prevents measles
The Cochrane review estimated about 95% measles protection after one MMR dose in children. Protection is high, not perfect. Measles can cause pneumonia, brain inflammation and death. Live MMR is not suitable during pregnancy or for some people with severe immune suppression; individual eligibility needs medical assessment.
Safety and side effects
MMR can cause fever. CDC estimates roughly one fever-related seizure per 3,000–4,000 MMR recipients. Low platelets and severe allergy are rare. MMRV, which also covers chickenpox, has a different first-dose seizure-risk comparison from MMR plus a separate chickenpox vaccine. These numbers should not be merged.
MMR does not cause autism
The review’s autism analysis included two observational studies totaling 1,194,764 children and found no increased risk. That is the autism sample, not the total population across every outcome in the review.
Vitamin A supports care, not a replacement for vaccination
Clinicians can use vitamin A in measles care and to correct deficiency. Community supplementation studies in particular settings found low-certainty evidence of fewer measles cases. That does not show that high-dose supplements replace MMR in well-nourished children. Excess vitamin A can harm; treatment needs medical supervision.
Surviving measles has a cost
Measles can erase parts of the antibody memory built against other infections. The study measured the range of antibodies measured—not the percentage of a child’s entire immune system destroyed. Avoiding measles avoids this damage as well as the initial illness.
Outbreak viruses can be identified
In the 2025 Kansas, New Mexico and Texas investigation, all 208 genotyped outbreak specimens were wild genotype D8. Texas research published in 2026 also identified D8 from the 2025 outbreak. These were not vaccine-strain outbreaks. Finding vaccine RNA after vaccination and identifying contagious wild-type measles are different questions.
Measles vaccination prevents a highly contagious disease that can cause serious illness and death.
Keep in mind
- The findings apply to the vaccines, populations and outcomes studied. Personal recommendations depend on your health and current local guidance.
Find the answer you need
Sources you can check
Publication links open in a new tab, so you can keep your place here.
Vaccines for measles, mumps, rubella, and varicella in children (opens in a new tab)
Cochrane, 2021
Reviews effectiveness and harms in children. Different outcomes use different studies and participant totals.
Return to reading ↑Clinical Overview of Measles (opens in a new tab)
CDC
Explains complications, medical care and the supervised role of vitamin A.
Return to reading ↑Measles, Mumps, Rubella (MMR) Vaccine Safety (opens in a new tab)
CDC
Explains known MMR side effects; combined MMRV has a different seizure-risk comparison.
Return to reading ↑Statement of the WHO Global Advisory Committee on Vaccine Safety (GACVS) on vaccines and autism (opens in a new tab)
WHO, 2025
Assesses vaccine–autism evidence, including thimerosal and aluminum; this is not a finding of zero vaccine side effects.
Return to reading ↑Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age (opens in a new tab)
Cochrane, 2022
Community supplementation evidence, largely from lower-income settings; not a test of replacing MMR in well-nourished children.
Return to reading ↑Measles virus infection diminishes preexisting antibodies that offer protection from other pathogens (opens in a new tab)
Science, 2019
Measures loss of parts of antibody memory after measles, not a percentage of the whole immune system.
Return to reading ↑Measles Update — United States, January 1–April 17, 2025 (opens in a new tab)
CDC MMWR, 2025
Genotyping distinguishes wild virus from vaccine strains; not every US sample had the same wild genotype.
Return to reading ↑Whole-Genome Sequencing of Measles Virus from 2025 Outbreak, Texas, USA (opens in a new tab)
Emerging Infectious Diseases, 2026
Published in 2026 about the 2025 Texas outbreak; sequencing does not establish every transmission direction.
Return to reading ↑
Detailed research notes and source data
Our longer notes explain how we checked the studies, including disagreements and documents we could not get.
Download the detailed research notes →More research notes: supporting evidence →
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These pages have not completed expert review. For personal vaccine advice, talk to a clinician who knows your circumstances.
Research checked: . Wording reviewed: 2026-10-15. Version: vaccine-2026-10-15.
We revisit the page when new evidence or corrections change the answer. A public history of corrections is not available yet.