SOUTH SAN FRANCISCO, Calif., July 6, 2026
Vaxart, Inc. has announced positive topline 12-month safety results from the approximately 400-participant sentinel safety cohort of its Phase 2b clinical trial evaluating the company’s investigational oral pill COVID-19 vaccine against an approved mRNA COVID-19 vaccine. The study enrolled 201 participants who received Vaxart’s oral vaccine and 199 participants who received the comparator vaccine targeting the XBB strain of SARS-CoV-2. The trial reported no vaccine-related serious adverse events (SAEs) and no sustained Grade 3 or higher vaccine-related adverse events in either treatment group, supporting the favorable safety profile of Vaxart’s oral vaccine platform.
Safety Findings Support Continued Development of Oral Vaccine Platform
The most frequently reported adverse events among participants receiving the oral pill vaccine were malaise or fatigue (20.9%), headache (18.9%), and anorexia (10.0%), while fewer than 10% experienced any other adverse event. Participants who received the injectable mRNA vaccine most commonly reported injection site pain (60.3%), injection site tenderness (40.2%), malaise or fatigue (35.2%), muscle pain (33.2%), and headache (28.6%), along with other expected injection-related reactions. Throughout the 12-month follow-up period, both study arms demonstrated acceptable tolerability with no new safety concerns identified.
Efficacy Assessment Continues in Larger Main Cohort
Although the sentinel cohort was designed primarily to evaluate safety rather than efficacy, investigators reported 33 symptomatic COVID-19 cases among participants receiving the oral vaccine compared with 30 cases in the mRNA comparator group. Asymptomatic infections were reported in 12 participants in each study arm. Vaxart emphasized that the 400-participant safety cohort was not statistically powered to compare vaccine efficacy, and these findings should not be interpreted as evidence of comparative effectiveness.
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Phase 2b Program Progresses Toward 2027 Readout
The ongoing Phase 2b trial includes an additional approximately 5,000 participants in the main cohort, who received vaccines targeting the KP.2 SARS-CoV-2 variant that was prevalent when enrollment began. The larger study has been designed and powered to evaluate both relative efficacy and long-term safety between the oral vaccine and the approved mRNA comparator. Topline results from the complete Phase 2b trial are expected in 2027.
The program is supported through Project NextGen, a U.S. government initiative led by the Biomedical Advanced Research and Development Authority (BARDA) in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID). Vaxart’s award, valued at up to $344.8 million, supports the continued development of next-generation COVID-19 vaccines using the company’s proprietary oral pill vaccine technology, which is designed to simplify vaccine administration while eliminating the need for refrigeration and needle-based delivery.
Source: Vaxart press release
