COVID-19 vaccine tablet significantly reduces viral load in hamsters

Vaxart Inc., a clinical-stage biotechnology company developing vaccine tablets, has announced that its oral COVID-19 vaccine candidate potently induced an antibody response and significantly reduced the lung viral load in a hamster challenge study.

The enterprise added that two doses of the recombinant adenoviral oral vaccine protected the hamsters from intranasal challenge as well as intranasal vaccination. Indicators of this were:

• no systemic weight loss, compared to nine percent total loss in unvaccinated animals
• minimal change in lung weight, the weight of the lungs in unvaccinated hamsters was over two times that of the ones receiving the oral vaccine

• significant reduction in lung viral load (four or five log less) in hamsters that received two oral vaccine doses, as compared to non-vaccinated animals; and
• serum IgG antibody titers above 10,000 in hamsters that received two oral vaccine doses.

“These additional data provide further evidence supporting the efficacy potential of our oral COVID-19 vaccine candidate,” said Andrei Floroiu, chief executive officer of Vaxart. “In addition, we believe that our room-temperature-stable oral tablet vaccine would be a more convenient, more practical solution to the COVID-19 pandemic as compared to cold-chain dependent injectable vaccines.”

The company said that the hamsters in the study were vaccinated at zero and four weeks, then challenged with SARS-CoV-2 at week eight. According to the researchers, hamsters are considered an excellent model for assessing COVID-19 infection for several reasons: they can be infected intranasally; if infected, they demonstrate clinical symptoms such as weight loss, labored breathing and ruffled fur; and can also develop lung damage similar to that seen in humans, including lung inflammation.