In a recent study from Duke University, scientists found a new COVID vaccine designed to be taken orally not only protects the host, but also decreases the airborne spread of the virus to other close contacts.
They showed the potential of a COVID vaccine that works through the mucosal tissue to neutralize the SARS-CoV-2 virus, limiting infections and the spread of the active virus in airborne particles.
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.
There would be a substantial benefit to developing vaccines that not only protect against disease but also reduce transmission to unvaccinated people.
In the study, the researchers 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.
The team found in hamsters, the vaccine elicited a robust antibody response in blood and the 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, 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, mucosal immunizations increase the 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.
The findings demonstrate that mucosal immunization is a viable strategy to decrease the spread of COVID through airborne transmission.
The study focused on the original SARS-CoV-2 virus, and new studies will be designed to test the vaccine against Omicron variants.
If you care about COVID, please read studies about new ways to predict who will get severe COVID-19, and Omicron can be neutralized by a booster dose.
For more information about COVID, please see recent studies about treatment that may prevent COVID death and lung damage, and results showing CBD from cannabis may inhibit COVID-19 infection.
The research is published in Science Translational Medicine and was conducted by Stephanie N. Langel et al.
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