The Latest Development of Oral COVID-19 Vaccine May Reduce the Risk of Virus Airborne Transmission

At present, the vast majority of new crown vaccination methods are intramuscular injection. According to the data released by the US CDC, common adverse reactions after vaccination include pain and redness at the injection site. In addition, since the protective efficacy of the existing vaccines has not reached 100%, it is still possible to contract the COVID-19 after vaccination and transmit the virus through the respiratory tract.

On May 5, a study led by Duke University in the United States announced the experimental results of the new crown oral vaccine. The vaccine can neutralize the new coronavirus through mucosal tissue, limiting the airborne transmission of the virus. The research was published in the journal Science Translational Medicine.

Dr. Langel, vaccine developer Vaxart and the Lovelace Biomedical Research Institute, a clinical research organization, are testing an oral vaccine. The vaccine uses adenovirus as a vector and expresses the spike protein of the SARS-CoV-2 virus.

In experiments with hamsters, the vaccine elicited strong antibody responses in the blood and lungs. When experimental animals were exposed to high levels of SARS-CoV-2 to induce breakthrough infection, vaccinated individuals had less symptoms than unvaccinated individuals, reduced viral content in the nasal cavity and lungs, reduced lung pathological changes, and reduced air passage. Risk of spreading the virus.

Dr. Langel said that, unlike vaccines given intramuscularly, oral Covid-19 vaccines will improve mucosal immune function. Mucosal immunity is the first line of defense of the immune system, mainly distributed in the gastrointestinal tract and respiratory tract. IgA mainly exists in the mucosal tissue, which can inhibit the attachment of the virus to the respiratory epithelium and slow down the reproduction of the virus. Oral Covid-19 vaccine increases the body's IgA levels, which reduces the likelihood that a vaccinated person will spread the virus when they sneeze or cough.