An investigational Covid 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 that was conducted on hamsters.
The study, led by researchers from Duke University, demonstrated the potential of the vaccine that works through the mucosal tissue to neutralize the SARS-CoV-2 virus, limiting infections and the spread of active viruses in airborne particles, IANS reported.
“Considering most of the world is under-immunized – and this is especially true of children – the possibility that a vaccinated person with a breakthrough infection can spread Covid to unimmunized family or community members poses a public health risk,” said Stephanie N Langel, doctoral researcher at the university.
“There would be a substantial benefit to develop vaccines that not only protect against disease, but also reduce transmission to unvaccinated people,” she said.
The findings of the team have been published in the journal Science Translational Medicine.
Langel and her team – including teams from vaccine developer Vaxart and clinical research nonprofit Lovelace Biomedical Research Institute – tested a vaccine candidate that uses an adenovirus as a vector to express the spike protein of the SARS-CoV-2 virus. The human vaccine is designed to be taken as a pill.
In studies using hamsters, the vaccine elicited a robust antibody response in the blood and lungs.
When the animals were exposed to the SARS-CoV-2 virus at high levels, prompting breakthrough infections, they were less symptomatic than non-vaccinated hamsters and had lower amounts of infectious virus in the nose and lungs. Because of this, they did not shed as much virus through normal airborne exposures.
Unlike vaccines that are injected into the muscle, Langel said, mucosal immunization increases production of immunoglobulin A (IgA), the immune system’s first line of defense against pathogens, in the nose and lungs.
These mucosal ports of entry are then protected, making it less likely that those who are vaccinated will transmit infectious virus during a sneeze or cough.
“Our data demonstrate that mucosal immunization is a viable strategy to decrease the spread of Covid through airborne transmission,” Langel said.
Langel said the study focused on the original SARS-CoV-2 virus, and new studies will be designed to test the vaccine against Omicron variants.
