Why Rand Paul clashed with Susan Monarez over infant vaccines and vaccine policy at the CDC

Former CDC Director Susan Monarez testified before the Senate Health, Education, Labor, and Pensions (HELP) Committee on September 17, 2025, defending her scientific integrity amid allegations of political interference. Monarez claims she was fired after less than a month in office for refusing to commit to approving vaccine recommendations before reviewing supporting data, and for resisting directives from HHS Secretary Robert F. Kennedy Jr. to dismiss long-standing officials without cause.

Senator Rand Paul, alongside others, questioned Monarez sharply on her stance that vaccines for very young children, such as COVID-19 for 6-month-olds and the Hepatitis B shot at birth, should remain recommended only when backed by strong evidence. Paul pressed Monarez to justify the medical benefits and risks, repeatedly challenging the routine vaccine schedule and Monarez’s refusal to fire those who support early-childhood vaccine mandates.

Monarez Accuses RFK Jr. of Undermining Science

Monarez testified that Kennedy pressured her to support sweeping changes to the childhood vaccine schedule, including telling her that the schedule would begin changing in September, before reviewing any new evidence. She also said she was asked to pre-approve all vaccine board (ACIP) recommendations unconditionally and to fire senior scientists seen as obstacles.

According to Monarez, the changes lacked scientific backing and were pushed forward through a newly reconstituted advisory board populated in part by vaccine skeptics. She argued the alterations threatened public health, and that her refusal to comply with these directives was the real reason for her removal.

Rand Paul’s Key Concerns: Infants, Vaccines, and Evidence

During the hearing, Rand Paul challenged Monarez on whether it’s justified to administer the COVID-19 vaccine to infants as young as six months, asking what clinical evidence supports reductions in hospitalization or death. Monarez countered that recommendations are meant to be evidence-based, and that CDC guidance is not equivalent to mandates.

Paul also questioned the necessity of the Hepatitis B vaccine given at birth in cases where the mother is negative. These criticisms are part of a broader debate: whether routine childhood vaccine schedules should be revised or scaled back given concerns about scientific rigor, transparency, and potential side effects.

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Implications for Vaccine Trust and Public Health

Monarez warned that weakening evidence-based review and giving political appointees undue influence over vaccine policy risks returning vaccine-preventable diseases like measles. She noted recent outbreaks as warning signs. Senior CDC and public health officials have expressed concern that changes without rigorous science could undermine public trust and endanger children.

Her testimony highlighted worries that patients and physicians might face confusing or conflicting guidance, particularly if recommendations are adopted without transparent scientific validation. The reorganization of ACIP, and the removal and replacement of its members, has drawn criticism from both sides of the aisle.

What’s Next: Legal and Policy Fallout

While Monarez has been ousted, there are meetings scheduled soon for ACIP to vote on vaccine recommendations for COVID-19, hepatitis B, and MMR-varicella. Changes she resisted may still be pushed forward under the new advisory board structure.

Her legal team is highlighting concerns about free speech and scientific integrity, and there may be further congressional oversight. The hearing has already prompted some Republicans and Democrats alike to express regret and concern over how the CDC and vaccine policy have been handled under political pressure.

Frequently Asked Questions (FAQ)

Why did Rand Paul clash with Susan Monarez?

Rand Paul pressed former CDC Director Susan Monarez on the evidence for recommending vaccines to infants, especially COVID-19 shots for 6-month-olds and Hepatitis B at birth. He argued the recommendations lack sufficient proof of benefit, while Monarez defended an evidence-based process.

What did Susan Monarez reveal about RFK Jr.’s role in vaccine policy?

Monarez testified that Health Secretary Robert F. Kennedy Jr. pressured her to pre-approve vaccine schedule changes without reviewing scientific data and to fire senior CDC officials seen as obstacles. She said her refusal led to her firing.

Are vaccines for 6-month-old infants supported by science?

Monarez explained that CDC recommendations are based on studies showing protection against hospitalization and severe illness, but emphasized that recommendations are not mandates. Critics like Rand Paul want clearer proof before advising parents to vaccinate infants.

What is happening to the CDC’s vaccine advisory board (ACIP)?

The Advisory Committee on Immunization Practices (ACIP) was restructured with new members, some of whom are vaccine skeptics. Critics say this threatens scientific independence, while supporters argue it makes the process more transparent.

How could changes to the vaccine schedule affect public health?

Monarez warned that weakening evidence-based reviews could undermine public trust and trigger a resurgence of diseases like measles. She urged lawmakers to keep politics out of scientific decisions.

Can Susan Monarez challenge her removal from the CDC?

Her legal team argues she was ousted for refusing political interference. While she cannot regain her position, congressional oversight and future investigations could bring more scrutiny to her dismissal.