Let's Talk about Vaccination Status in Measles Outbreaks
What's the difference between Unvaccinated or Unknown?
While most of us understand that the great majority of folks in a measles outbreak are unvaccinated, anti-vaccine influencers go to great lengths to try and convince their followers they are actually vaccinated.
How do they do that?
Let's Talk about Vaccination Status in Measles Outbreaks
They do it by abusing the way that the CDC displays the Vaccination Status of measles cases.
Not surprisingly, the CDC groups the Unvaccinated and the Unknown vaccination status folks together, as you can’t just assume that the Unknown are immune.
Why are they Unknown?
Probably because they say they don’t remember if they were vaccinated, and they don’t give their immunization records to public health experts investigating the outbreak.
And unfortunately, multiple studies have shown that parental recall of immunization history is typically not very good.
Now, since most of these cases are in Texas, where we have had an online immunization registry since 2010, you would think it would be easy to eliminate all of these Unknown vaccination statuses if they had really received an MMR vaccine, wouldn’t you?
“Regarding vaccination status, most of the observed measles cases (1828, 81.1%) were unvaccinated. Only 9.8% (220 cases) had received one measles vaccine dose prior to the outbreak, and 3.9% (89 cases) have received two prior measles vaccine doses. In 117 cases (5.2%), vaccination status could not be validated against a vaccination record or via the national immunization registry.”
Case Ascertainment of Measles during a Large Outbreak—Laboratory Compared to Epidemiological Confirmation
That’s what they found when they studied the vaccination status of everyone in a large measles outbreak in Israel, which has a national immunization registry.
Researchers have found much the same when they studied the vaccination status in measles outbreaks in Austria, Canada, and UK, etc.
The overwhelming majority of the cases were unvaccinated.
And not surprisingly, the two deaths this year in Texas and New Mexico were in people who were unvaccinated.
Want to know who’s getting measles?
It is almost always people, often children, who are unvaccinated.
#StopTheOutbreaks.
References
Case Ascertainment of Measles during a Large Outbreak—Laboratory Compared to Epidemiological Confirmation. https://www.mdpi.com/2075-4418/14/9/943
Henszel L, Kanitz EE, Grisold A, Holzmann H, Aberle SW, Schmid D. Vaccination Status and Attitude among Measles Cluster Cases in Austria, 2019. Int J Environ Res Public Health. 2020 Dec 15;17(24):9377. doi: 10.3390/ijerph17249377. PMID: 33333819; PMCID: PMC7765158.
Dorell CG, Jain N, Yankey D. Validity of parent-reported vaccination status for adolescents aged 13-17 years: National Immunization Survey-Teen, 2008. Public Health Rep. 2011 Jul-Aug;126 Suppl 2(Suppl 2):60-9. doi: 10.1177/00333549111260S208. PMID: 21812170; PMCID: PMC3113431.
Measles and Rubella Weekly Monitoring Report: Week 8 (February 16 to February 22, 2025) https://www.canada.ca/en/public-health/services/publications/diseases-conditions/measles-rubella-surveillance/2025/week-8.html
Laboratory confirmed cases of measles, mumps and rubella in England: July to September 2024. Updated 20 December 2024. https://www.gov.uk/government/publications/measles-mumps-and-rubella-lab-confirmed-cases-in-england-2024/laboratory-confirmed-cases-of-measles-mumps-and-rubella-in-england-july-to-september-2024
They would have to be 'unvaccinated' since this is the status used to make a 'measles' diagnosis. 'unvaccinated' does not however mean they weren't given a dose of the 'vaccine'. This is because it is a status. you might compare with divorce. If you file for divorce it might take a year before your status is actually changed and during that time you would be still considered married.