US halts COVID-19 vaccine trial by Vaxart amid shift towards mRNA technology.

The US government has ordered Vaxart to halt its COVID-19 vaccine trial amid a global shift towards mRNA vaccines. The decision follows a decline in interest in non-mRNA vaccines, which use a different technology to deliver genetic material into cells. Vaxart's vaccine uses a virus-like particle to deliver genetic material, but the company has struggled to secure funding and partnerships for its vaccine. The US government's decision to end the trial means that Vaxart's vaccine will not be tested in humans.

The U.S. government has ordered Vaxart to halt its COVID-19 vaccine trial, marking a significant setback for the biotechnology company [1]. The decision comes amidst a global shift towards mRNA vaccines, which use a different technology to deliver genetic material into cells. Vaxart's vaccine employs a virus-like particle to achieve this, but the company has faced challenges securing funding and partnerships for its product.

The halt order, issued on August 5, 2025, halts Vaxart's Phase IIb trial for its oral COVID-19 vaccine, VXA-CoV2-3.3 [1]. The company was developing this vaccine with support from the Biomedical Advanced Research and Development Authority (BARDA), which had awarded up to $460 million for the project. Vaxart had enrolled approximately half of its target participants in the trial when the order was issued.

The U.S. Department of Health and Human Services (HHS) did not provide a specific reason for the halt order, only indicating that it would release further details in a follow-up notice [1]. The order follows a similar stop order issued in February 2025, which was later lifted in April.

The halt order is part of a broader shift in U.S. vaccine policy under Health Secretary Robert F. Kennedy Jr. [1]. In August, Kennedy terminated 22 mRNA vaccine projects under BARDA, including those for COVID-19 vaccines. This move came on the same day as the new stop work order for Vaxart's protein-based vaccine.

Vaxart's financial performance in the second quarter of 2025 reflects the challenges it faces. The company reported GAAP revenue of $39.7 million, up 520.3% year-over-year, driven primarily by government contract income [2]. However, the company recorded a net loss of $15.0 million, reflecting high research and development expenses of $49.7 million. The company's cash balance stood at $26.3 million at the end of the quarter, down from $41.9 million at the end of the first quarter of 2025.

The halt order for Vaxart's COVID-19 vaccine trial adds uncertainty to the company's future prospects. Vaxart's oral vaccine platform offers a pill alternative to injections and mRNA-based vaccines, but it faces competition from established vaccine makers such as Pfizer and Moderna. The company's reliance on government contracts for funding and its high cost base pose operational challenges.

References:
[1] https://www.biospace.com/policy/hhs-freezes-vaxarts-oral-covid-19-vaccine-again
[2] https://www.nasdaq.com/articles/vaxart-revenue-jumps-520-fiscal-q2