The Infodemiology Brief —

Federal health agency vaccine actions fuel confusion and hesitancy

Outbreaks over the winter holidays sparked debate about herd immunity.

In December, the FDA announced a safety review of COVID-19 and RSV immunizations, despite no serious safety concerns being linked to either vaccine. The announcement came amidst rising cases of several vaccine-preventable diseases and an ongoing online debate about the importance of routine vaccines and herd immunity. In response, some social media users accused federal health agencies of undermining trust in vaccines. In the weeks that followed, the CDC removed six immunizations from the childhood vaccine schedule. The change sparked pushback from medical experts and confusion from the public.

For even more resources, check out the menu above for real-time insights, training resources, and more. Specifically curated for people working in health care and public health, these links provide actionable content to help navigate today’s information landscape.

Trending narratives from the past month

Confusion and concern follow CDC overhaul of childhood vaccine schedule
On January 5, the CDC removed six immunizations from its childhood vaccine schedule. The change, which was made without expert input or a clear scientific rationale, reduced the number of immunizations recommended for all children from 17 to 11. Under the revised guidance, several routine immunizations—including COVID-19, flu, RSV, hepatitis A, hepatitis B, bacterial meningitis, and rotavirus—are now recommended only for high-risk children or through shared clinical decision-making. A growing number of state governments and health organizations rejected the updated schedule, citing a lack of transparency and warning that the move undermines scientific integrity. Online commenters expressed confusion about whether the change would reduce vaccine uptake or affect vaccine cost and access. Supporters of the overhaul shared false claims about vaccine safety and alleged, without evidence, that children in the U.S. are “overvaccinated.” This reframed the policy shift as a correction rather than a departure from established, evidence-based public health practice. Read the fact checks here and here.

FDA safety reviews of RSV and COVID immunizations fuel distrust in federal health agencies
On December 9, the FDA announced investigations into the safety of RSV immunizations for infants and COVID-19 vaccines for people of all ages. The announcements came just weeks after the agency publicly suggested—without evidence—that COVID-19 vaccines may be linked to several child deaths, prompting widespread concern among clinicians and public health experts. Online, many users questioned why RSV immunizations were singled out for review, noting that no safety concerns have been linked to them. Others expressed alarm that the FDA may be preparing to roll back approval of RSV immunizations and COVID-19 vaccines altogether, citing a broader pattern of recent reversals of longstanding, evidence-based vaccine policies. Conversations point to intensified skepticism across the information landscape. Vaccine opponents and supporters alike questioned the credibility and trustworthiness of federal health agencies, though for different reasons. While many vaccine opponents used the moment to call for broader vaccine restrictions, some voiced continued support for RSV immunizations that are monoclonal antibodies rather than vaccines. Read the fact checks here, here, and here.

Rising infections drive conversations about the importance of routine vaccines
Throughout December, rising cases of multiple vaccine-preventable diseases fueled online conversations about vaccine effectiveness and herd immunity. The U.S. reported 2,065 measles cases in 2025—the highest number since 1991—putting the country at risk of losing its measles elimination status. In December, measles outbreaks in South Carolina, Utah, and Arizona continued to expand as confidence in the MMR vaccine declined. As flu cases and hospitalizations surged nationwide, social media users discussed the severity of the dominant flu strain, noting that it is not well matched to this season’s vaccine. Some emphasized that vaccination still plays a critical role in reducing the risk of severe illness, complications, and hospitalization, even when strain matching is imperfect. Meanwhile, whooping cough infections continued to rise, prompting some online users to falsely claim that vaccines are ineffective and unsafe. Read the fact checks here, here, and here.

What you might say in response

The CDC’s guidance may have changed, but the science hasn’t: Childhood vaccines remain safe, effective, and available.

  • There is no clear scientific justification for changing the childhood immunization schedule. Decades of research show that routine childhood vaccines are safe, effective, and essential for preventing serious and sometimes deadly diseases.
  • Vaccine schedules are designed to protect children before they’re exposed to deadly diseases like measles, whooping cough, and polio. Delaying or skipping vaccines increases the risk of severe illness, complications, and outbreaks. 
  • Major medical organizations—including the American Academy of Pediatrics, the American Medical Association, and the American Academy of Family Physicians—have rejected the revised CDC schedule and continue to support long-standing, evidence-based vaccine recommendations. 
  • Parents can still choose to follow the previous, science-based immunization schedule. Health care providers are not required to follow the CDC’s revised guidance and can continue recommending routine vaccines based on the best available medical evidence.

RSV and COVID-19 immunizations protect people of all ages against severe illness, hospitalization, and death.

  • RSV hospitalizes more infants each year than any other infectious disease. RSV immunization reduces the risk of infant hospitalization by 80-90 percent. 
  • No safety concerns have been linked to pediatric RSV immunizations. These products were rigorously tested before approval and continue to be closely monitored for safety through multiple vaccine safety systems.
  • COVID-19 vaccines protect against severe illness, hospitalization, long COVID, and death. After more than five years of research and real-world use, there is no evidence of widespread safety linked to COVID-19 vaccination.
  • Vaccine safety monitoring is ongoing and continuous. Reviews and surveillance are part of how vaccines are monitored after approval and do not, on their own, mean a vaccine is unsafe. 
  • You can find reliable, science-based information about vaccines from trusted medical sources like the Children's Hospital of Philadelphia Vaccine Education Center and the American Academy of Pediatrics.

Vaccines protect you, your family, and your community. Low vaccination rates lead to outbreaks and preventable deaths.

  • Vaccination doesn’t just protect individuals—it protects entire communities. When vaccination rates fall, outbreaks become more likely, putting people of all ages at risk.
  • Herd immunity helps protect everyone, especially those who are most vulnerable, like infants, young children, older adults, and people with weakened immune systems.
  • The flu vaccine reduces the risk of infection, severe illness, hospitalization, and death—even in years when the vaccine is not a perfect match to circulating strains. Major medical organizations continue to recommend annual flu vaccination as the best protection against serious flu-related outcomes. 
  • Outbreaks of diseases like whooping cough and measles place unvaccinated people at risk, especially infants and children who are too young to be fully vaccinated. 
  • Routine vaccination dramatically lowers children’s risk of infection, severe illness, long-term complications, and death, while also helping to prevent the spread of disease to others.

What we’re reading

Don’t miss the Common Health Coalition’s 2-4-2 Digest, a weekly snapshot that provides four key insights for health leaders that can be read in two minutes or with two swipes on your phone. Sign up for the next weekly edition.

Studies and trainings

Sign up for the Trusted Messenger Program, a comprehensive series of online or in-person trainings, resources, models, and workshops that help health care providers develop the skill they use most and that is most critical to their success: communication.

Interested in learning more about how to debunk false claims with patients? Check out the Infodemiology Training Program. In videos that range from 5 to 10 minutes each, the program introduces health care providers to the basics of infodemiology and provides you with actionable skills to help improve patient care. Get started today.

The Health Care Infodemiology Brief is brought to you by PGP, the health care leadership of the Trusted Messenger Program, and Infodemiology.com’s sponsors and partners.