Measles in 2024: Online conversations spike as U.S. cases rise

Measles in 2024: Online conversations spike as U.S. cases rise

In November 2023, the CDC and WHO released a joint report about the rising threat of measles worldwide. The report detailed how over 30 million children missed routine measles vaccinations in 2022, contributing to an 18 percent increase in measles infections and a 43 percent increase in measles deaths. The report was a stark reminder of how a drop in immunization enables highly contagious infectious diseases to re-emerge.  

Now, a similar scenario is playing out in the U.S., with childhood immunization rates dropping to the lowest recorded in a decade and measles outbreaks reported in more than a dozen states since the beginning of the year. According to the CDC, MMR coverage in the U.S. is below the 95 percent threshold for herd immunity, and a dozen states have MMR immunity below 90 percent.

The COVID-19 pandemic severely disrupted routine immunization efforts in the U.S. and globally. However, the lingering effects of COVID-19 vaccine disinformation are helping to fuel a decline in vaccine confidence and growing hesitancy about well-established vaccines like MMR. A recent KFF poll found that one in six parents had encountered the false claim online that the measles vaccination is more dangerous than a measles infection, and, of those, a quarter believed the claim to be true.

To better understand false and misleading narratives about measles and measles vaccines, we analyzed social media, news, video, and online discussion posts between September 2023 and March 2024. This analysis includes major social media platforms, including Facebook, Instagram, X (formerly Twitter), and YouTube, as well as the content and comments of news, blogs, and forum sites. For information on the methods of PGP’s Monitoring Lab, please head here.

Key takeaways:

  • Rising measles outbreaks in the U.S. and worldwide fueled a 400 percent increase in online discourse about measles and MMR vaccines.

  • Unlike other recent infectious disease vaccine conversations, the vast majority of online measles discourse was explicitly pro-vaccine and critical of anti-vaccine narratives. 

  • Florida’s response to its recent measles outbreak dominated online discourse, with most conversations criticizing the governor and surgeon general.

  • False narratives about measles centered around four themes: 1) minimizing the severity of measles; 2) blaming migrants for measles outbreaks; 3) questioning the effectiveness of measles vaccines; and 4) circulating the myth that vaccines cause autism.

  • Anti-vaccine tactics and messaging popularized during the COVID-19 pandemic are being recycled in response to measles outbreaks.

Overview of measles outbreaks

As of March 14, 2024, the U.S. has recorded at least 58 measles cases in 17 states, matching the number of cases recorded in all of 2023. In the three years prior to 2023, measles cases were reported in less than half the number of jurisdictions with outbreaks so far this year.

In just the first quarter of 2024, measles outbreaks have emerged in every region of the country. During a measles outbreak in Broward County, Florida, the state’s surgeon general sent a controversial letter to parents that did not encourage vaccination and allowed unvaccinated children to continue attending school. The Chicago Department of Public Health announced on March 10 that the CDC sent a team to help contain the city’s growing outbreak.

On March 18, the CDC issued a health alert encouraging health providers to ensure people 6 months and older are up to date on their MMR vaccinations before traveling internationally. According to the agency, 93 percent of reported U.S. cases were linked to international travel, and most were young children not vaccinated against measles.  

2024 U.S. Measles Outbreak Timeline




Early Jan.: Philadelphia

Jan. 3-4: Northern Virginia Airports

Jan. 5-8: Camden County, NJ

Jan. 12: Clay County, MO 

Jan. 18: Atlanta, GA 

Jan. 19: Southwest WA 

Jan. 25: Los Angeles, CA

Feb. 2: Montgomery
County, MD
; San Diego, CA

Feb. 3: Montgomery County, OH

Feb. 12: Twin Cities, MN

Feb. 14: Maricopa County, AZ

Feb. 16: Broward County, FL

Feb. 22: New Orleans, LA

Feb. 23: Miami County, OH; Lake County, IN; Oakland County, MI

Feb. 26: Polk County, FL

Mar. 1: New York, NY

Mar. 3: Waye and Washtenaw Counties, MI

Mar. 11: Coconino County, AZ

Mar. 10: Chicago, IL - CDC sends team to assist with outbreak

Mar. 14: Stanislaus County, CA; Chicago, IL 

March 18: CDC issues a measles health alert

Online conversations about measles began increasing in September 2023. Between September 1, 2023 and March 2, 2024, 464,616 posts related to measles have been recorded across all platforms, with about 80 percent (366,186 posts) recorded in 2024 alone. The number of measles posts has increased by more than 400 percent, with the largest increase occurring between December 2023 and January 2024, when measles outbreaks were reported in Philadelphia. Measles discourse has continued to trend up through early March 2024.

There were six main spikes in online measles discourse during the analyzed period, all of them since January 2024. Two spikes (1, 2) correspond with new measles outbreaks, and two (4, 5) with Florida’s response to its ongoing outbreak. The other two spikes are related to news coverage of a New York health care provider fined for falsifying the vaccine records of unvaccinated children (3) and former President Trump’s campaign promise to defund public schools that mandate vaccines (6).

The overwhelming majority of the top posts related to measles were explicitly pro-vaccine (71 percent) or neutral (27 percent). To determine how narratives around measles compare to those related to other recent resurgences of infectious diseases in the U.S., we analyzed posts related to the 2022 New York polio outbreak.

Half of the top posts in the three months after polio was detected in Rockland County, New York, were pro-vaccine, and only 3 percent were anti-vaccine. Nearly half of the pro-measles vaccine posts originated from non-news sources, compared to only 14 percent of positive posts about polio vaccines. This may reflect a more positive public perception of measles vaccines compared to other types of vaccines.

Online measles vaccine discourse primarily criticized anti-vaccine sentiments and the Florida surgeon general, discussed global outbreaks and vaccination efforts, and encouraged vaccination. Overall, measles generates higher public interest than polio, perhaps due to the rarity and small scale of the polio outbreaks and the history of false information about MMR vaccine safety in the U.S.

Two popular anti-measles vaccine posts were authored by a political commentator with millions of followers and a vaccine injury attorney who have both advocated against childhood immunization in the past. In one video the social media user stated that vaccines are unnecessary because measles and mumps are mild diseases that don’t kill many people. They refer to mumps as “basically a bad sore throat.” In another example,  MMR was used as an example of a vaccine that caused so many alleged injuries that vaccine manufacturers faced “crushing liability,” resulting in the National Childhood Vaccine Injury Act of 1986.

Florida dominated online measles discourse

Florida has emerged as a topic of multiple trending measles conversations in the last two months. About 18 percent of all measles conversations since January 2023 specifically reference Florida.

An analysis of discourse specifically mentioning the Florida governor and surgeon general or the Broward County outbreak revealed that most were either critical of the surgeon general and anti-vaccine attitudes generally or neutral, reporting on the state’s response to the outbreak. None of the top posts voiced support for Florida officials. Notably, popular accounts that have typically supported these officials have not mentioned the topic.

Only a small portion of the top posts about measles were false. However, trending false narratives about measles and measles vaccines were observed, including general anti-vaccine sentiment, distrust of health authorities, and downplaying of the disease’s severity or the vaccine’s effectiveness.

False narrative #1: Measles isn’t serious enough to warrant vaccination.

A common theme in anti-vaccine conversations about measles is a minimization of the dangers the disease poses, often by dismissing it as just a rash or “normal childhood disease.” Many posts tout unproven “alternative” treatments like vitamin supplements instead of vaccination. The focus on the individual experience of measles as a mild, non-threatening disease echoes COVID-19 narratives by emphasizing low mortality and natural immunity.

False narrative #2: Border policies cause measles outbreaks.

An increasingly popular false narrative is that “open borders” and an influx of immigrant populations are to blame for current measles outbreaks. This talking point has been used in response to disease outbreaks for centuries. From September 2023 to March 2024, over 8,500 posts claim that unvaccinated migrants bring measles and other diseases to the U.S. There is no evidence to support this false claim.

False narrative #3: Measles vaccines don’t work.

Some anti-measles vaccine posts claim that the recent measles cases, which are primarily linked to unvaccinated or under-vaccinated individuals, are evidence that vaccines don’t work. Some posts question the effectiveness of the measles vaccine, falsely claiming that it does not confer immunity, while others claim that the decline in measles and other infectious diseases was due to improved sanitation rather than to vaccines. At times, social media posts claim that because COVID-19 vaccines allegedly “didn’t work,” the public shouldn’t think that measles vaccines work either.

False narrative #4: Autism myths but not specific to MMR

Perhaps the most prevalent and enduring anti-vaccine myth is the false claim that the MMR causes autism. However, despite the continued circulation of this myth, it had little impact on online discourse about the MMR vaccines. Most popular posts mentioning “MMR” and “autism” were debunking the myth. The relative absence of the autism myth in top posts is particularly interesting because other recent anti-vaccine narratives related to COVID-19, polio, and HPV vaccines rely heavily on emphasizing their alleged safety concerns.

To better understand how the vaccine-autism myth was referenced in online discourse, we expanded our analysis to include general vaccine conversations. Between February 5 and March 5, “vaccines” and “autism” were mentioned over 85,000 times, with only 5 percent explicitly referencing MMR. Moreover, the most popular posts linking MMR to autism garnered relatively little engagement. One possible interpretation of this finding is that the belief that vaccines broadly cause autism has supplanted the belief that MMR vaccines specifically cause autism.

Other measles narratives to monitor

  • Immune amnesia misconceptions: Posts and videos about measles’ unique ability to cause immune amnesia have led to some unfounded assumptions about the phenomenon. One post suggests that measles immune amnesia will make COVID-19 deadlier, while another post questions if measles vaccines can cause immune amnesia.
  • 2024 election: Some social media users have insinuated that measles outbreaks are being emphasized or exaggerated to influence the upcoming U.S. presidential election. This narrative is similar to claims about COVID-19 in the lead-up to the 2020 presidential election.
  • General fear-mongering and conspiracy theories: Local news coverage of measles outbreaks has prompted some online to link them to COVID-19 conspiracy theories. There are many examples of social media users responding to measles outbreaks with some variation of “Here we go again” and insinuating that pandemic policies will return.