A tested pill vaccine designed to be taken as a pill neutralizes the SARS-CoV-2 virus in mucosal tissues such as the nose and lungs, according to a study conducted on hamsters.
The study, led by researchers at Duke University, demonstrated the potential of a Covid vaccine that works through mucosal tissue to neutralize SARS-CoV-2 virus, limiting infections and the spread of active virus in airborne particles.
“Given that much of the world is under-immunized – and this is especially true for children – the possibility of a vaccinated person with a breakthrough infection can spread Covid to non-immunized family or community members poses a risk to public health.” said Stephanie N. Langel, a doctoral student at the university.
“There are significant benefits to developing vaccines that not only protect against disease but also reduce the transmission of unvaccinated people,” Langel added.
The results are published in the journal Science Translational Medicine.
Langel and a team, including teams from the vaccine developer, Vaxart and the nonprofit Lovelace Biomedical Research Institute for Clinical Research, tested a vaccine candidate that uses adenovirus as a vector to express the SARS-CoV-2 virus. The human vaccine is intended to be taken as a pill.
In studies using hamsters, the vaccine caused a strong response to antibodies in the blood and lungs.
When the animals were exposed to high levels of the SARS-CoV-2 virus, which caused breakthrough infections, they were less symptomatic than unvaccinated hamsters and had lower levels of infectious virus in the nose and lungs. As a result, they do not shed as much virus through normal air exposure.
Unlike vaccines that are injected into a muscle, Langel said, mucosal immunizations increase the production of immunoglobulin A (IgA) – the first line of defense for the immune system against pathogens – in the nose and lungs.
These mucosal entry ports are then protected, making vaccinated less likely to transmit an infectious virus during sneezing or coughing.
“Our data show that mucosal immunization is a viable strategy to reduce the spread of Covid by airborne transmission,” Langel said.
Langel said the study focuses on the original SARS-CoV-2 virus and new studies will be created to test the vaccine against Omicron variants.
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