Moderna will carry out a placebo-controlled trial of its new COVID-19 vaccine, and the Food and Drug Administration will keep tabs on the trial, Health Secretary Robert F. Kennedy Jr. said on June 3.
“I want to address those of you who have anxieties about FDA’s limited approval of a new mRNA COVID vaccine for high-risk populations,” Kennedy wrote on social media platform X. “Moderna has agreed to a true placebo-controlled trial of the new vaccine.”
Moderna already has a COVID-19 vaccine, called Spikevax, on the market. The new vaccine, approved by health officials on May 31, is known as mNEXSPIKE. A Moderna spokesman confirmed to The Epoch Times that mNEXSPIKE utilizes messenger ribonucleic acid (mRNA) technology, just like Spikevax, but did not answer additional questions.
The Department of Health and Human Services (HHS), Kennedy’s agency, had announced in April that “under the Secretary’s leadership, all new vaccines will undergo safety testing in placebo-controlled trials prior to licensure.”
A spokesperson for the HHS told The Epoch Times in an email on Wednesday: “This approval was for high-risk individuals. Approvals for healthy people will still have to go through placebo-based trials.”
Top officials with the FDA, which is part of HHS, said in May that they would approve COVID-19 vaccines for the elderly and young people with one of the risk conditions based on immunogenicity data, but that they would require trial data to approve the vaccines for others. The officials said such trials could include saline placebos.
The Centers for Disease Control and Prevention, under orders from Kennedy, then stopped recommending COVID-19 vaccines to healthy children and pregnant women.
Approval Based on Trial
The FDA licensed mNEXSPIKE for previously vaccinated adults aged 65 and older. People aged 12 to 64 who have at least one condition, such as obesity, that authorities say places them at higher risk for severe COVID-19, and who received a COVID-19 vaccine before, can also take the shot, which Moderna says will be available later in the year.
Officials said in the approval letter for the new vaccine that Moderna had committed to a phase 4 post-approval, randomized, placebo-controlled study to evaluate the safety and efficacy of mNEXSPIKE. The study will be conducted in adults aged 50 to 64 without one of the risk conditions, according to the letter.
The study will be initiated in November 2025, will be completed in mid-2026, and final results will be provided to regulators on Jan. 31, 2027, the FDA said.
“The FDA will monitor and collect data throughout the trial for every adverse outcome—not just a table list of expected outcomes,” Kennedy said on Tuesday. “FDA will scrutinize every aspect of the trial. We will deliver on our promise to use gold standard science and common sense.”
Barbara Loe Fisher, co-founder and president of the National Vaccine Information Center, told The Epoch Times in an email that there is insufficient data at present regarding adverse events among the elderly and people with one of the risk conditions following mRNA vaccination, but that she was encouraged that Kennedy “has reassured the public that the FDA will require Moderna to conduct a true placebo controlled clinical trial of mNEXSPIKE and collect data for every adverse outcome, not just expected outcomes.”
Moderna ran a trial prior to approval that compared the immune reactions and number of COVID-19 infections among participants who received mNEXSPIKE and people who received a version of Moderna’s existing vaccine. The mNEXSPIKE arm had the same or better immunogenicity, and a lower percentage of mNEXSPIKE recipients contracted COVID-19 or severe COVID-19, according to the company. The relative vaccine efficacy against symptomatic COVID-19 was 9.3 percent.
Moderna CEO Stéphane Bancel said in a statement that the approval of mNEXSPIKE “adds an important new tool to help protect people at high risk of severe disease from COVID-19.”

