HHS Halts Vaxart's Oral COVID-19 Vaccine Trial Amid Broader Policy Shifts

The Department of Health and Human Services (HHS) has issued a stop order for Vaxart's Phase IIb trial of its oral COVID-19 vaccine candidate, VXA-CoV2-3.3. This decision, announced on August 5, 2025, marks the second time this year that the California-based company's vaccine development has been frozen by federal authorities.

Vaxart's Vaccine Development Setback

Vaxart's VXA-CoV2-3.3 is an orally administered, protein-based vaccine designed to provide broad protection against SARS-CoV-2 variants. The company had enrolled approximately 5,000 participants in its 10,000-person Phase IIb trial, which aimed to compare the efficacy of VXA-CoV2-3.3 with Pfizer and BioNTech's mRNA-based Comirnaty vaccine.

The biotech firm, which received up to $460 million in funding from the Biomedical Advanced Research and Development Authority (BARDA), has been instructed to halt further patient screening and enrollment. However, Vaxart is permitted to continue follow-up efforts for participants who have already received doses.

This latest setback follows a similar stop order issued in February, which was subsequently lifted in April. The HHS has not provided a specific reason for the current freeze, stating only that a "follow-up notice with further details" will be forthcoming.

HHS Policy Shifts Under New Leadership

The stop order coincides with broader policy changes implemented by newly appointed Health Secretary Robert F. Kennedy Jr. On the same day as Vaxart's trial suspension, Kennedy terminated 22 mRNA vaccine projects under BARDA, resulting in the cancellation of approximately $500 million in contracts.

These actions align with Kennedy's well-documented skepticism towards vaccines. In recent months, he has announced plans to "fix" the U.S. Vaccine Injury Compensation Program, citing concerns about inefficiency and corruption. Additionally, in May, Kennedy removed routine COVID-19 vaccination recommendations from CDC guidelines for healthy children and pregnant women, a decision that has drawn criticism from medical societies.

Industry Implications and Future Outlook

The suspension of Vaxart's trial and the cancellation of multiple mRNA vaccine projects signal a significant shift in U.S. vaccine policy. These developments raise questions about the future of COVID-19 vaccine research and development in the United States, particularly for next-generation and alternative delivery methods such as Vaxart's oral formulation.

As the pharmaceutical industry awaits further clarification from HHS regarding these policy changes, the long-term impact on vaccine innovation and pandemic preparedness remains uncertain. The outcome of Vaxart's trial suspension and the broader implications of the new HHS directives will likely be closely watched by industry stakeholders and public health officials alike.