Fact Check: 96.3% of measles cases in children were unimmunized!

Fact Check: "96.3% of measles cases in children were unimmunized!"

What We Know

The claim that "96.3% of measles cases in children were unimmunized" appears to be based on data regarding measles cases and vaccination status. According to the CDC, as of June 19, 2025, a total of 1,214 confirmed measles cases were reported in the U.S., with 89% of these cases being outbreak-associated. Notably, a report from the CDC indicated that among all measles patients, 771 (96%) were unvaccinated or their vaccination status was unknown, while only 10 (1%) had received one dose of the MMR vaccine (source-4).

Additionally, a systematic review highlighted that in various studies, 71% to 91% of confirmed measles cases had received no doses of the measles-containing vaccine (MCV) (source-2). This suggests a significant correlation between being unimmunized and contracting measles.

Analysis

The claim's accuracy hinges on the interpretation of the data regarding vaccination status among measles cases. The CDC's report that 96% of measles cases were unvaccinated or had an unknown vaccination status supports the assertion that a high percentage of cases were among unimmunized children (source-4). However, it is important to note that this statistic includes cases where the vaccination status is unknown, which could skew the perception of the data.

The systematic review also indicates that a significant portion of measles cases in various studies were among those who had not received any doses of the MCV, reinforcing the idea that unimmunized individuals are at a higher risk for measles (source-2). However, the variability in the percentage of unimmunized cases across different studies (71% to 91%) suggests that the exact figure can fluctuate based on the population and context being examined.

The reliability of the sources is generally high, with the CDC being a primary health authority in the U.S. and the systematic review being published in a peer-reviewed journal. However, the context of the data must be considered, particularly the inclusion of cases with unknown vaccination status, which could lead to misinterpretation of the claim.

Conclusion

Needs Research. While there is substantial evidence suggesting that a high percentage of measles cases are among unimmunized individuals, the claim that "96.3% of measles cases in children were unimmunized" requires further investigation. The inclusion of cases with unknown vaccination status complicates the interpretation of the data, and more precise figures or additional context would be necessary to fully validate the claim.