Sanofi shut down its RSV vaccine trial for infants and toddlers in 2024 after a baby died. It was later determined that the baby had an underlying congenital heart defect, which should have disqualified the infant from participating in the trial.
Now, a newly obtained letter shows the company paused the trial “to re-educate all participating sites and investigators” on the criteria they should use to judge who should or shouldn’t be allowed to participate in the trial, and to “reiterate the need to assess for chronic illnesses” that would make an infant or toddler ineligible to participate in a clinical trial.
The letter — obtained through a Freedom of Information (FOI) request by British general practitioner and RSV vaccine expert Dr. Peter Selley — sheds new light on the infant death and trial pause first reported by The Defender.
The infant’s death constituted a “serious adverse event” that triggered the halt.
A Sanofi spokesperson last month confirmed the death and told The Defender that the baby had underlying congenital heart disease. The company’s analysis — supported by the independent data monitoring committee — the spokesperson said, concluded the experimental vaccine was not the “underlying cause of the event.”
Research published in the Pediatric Infectious Disease Journal indicates that most children who die from respiratory syncytial virus, or RSV, have comorbidities such as congenital heart or lung disease.
Congenital disorders should have excluded babies from the study, and participants should have been assessed for preexisting conditions, according to the clinical trial’s exclusion criteria.
“Given that they stopped the trial to ‘re-educate’ investigators about inclusion and exclusion criteria, it suggests that the trial protocol was not being followed in at least one of the trial sites,” Selley told The Defender.
Sanofi told The Defender that when the infant with an undiagnosed underlying heart condition died after receiving the experimental vaccine, the company proactively informed and worked closely with the independent data monitoring committee (IDMC) and health authorities to address the issue.
He said the U.S. Food and Drug Administration (FDA) put the trial on a clinical hold and the company worked “to amend the Phase 3 protocol, adjust and clarify screening procedures and inclusion criteria, and re-educate all participating sites and investigators.”
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