Needle-Free Covid Vaccines are (Still) in the Works
upstart writes:
Vaccines delivered through the nose or mouth should help stop infection where it begins:
The federal government is working to speed things along with an injection of cash through Project NextGen, a $5 billion effort to usher new and improved covid vaccines to market. In October, the Department of Health and Human Services announced that nearly $20 million would go to two companies developing mucosal vaccines-Codagenix and CastleVax. That money will help the companies gear up for studies to test how well their vaccines work to prevent symptomatic infections.
Codagenix's candidate, a nasal vaccine called CoviLiv, is already part of a phase 3 global efficacy trial coordinated by the World Health Organization. And in October, the company reported results from a safety study in adults in the UK who had never been vaccinated for covid before. The nasal mist prompted robust immunity, at least as measured by markers in the blood. But evidence of an immune response in the blood doesn't necessarily indicate an immune response in the mucosal lining of the airways. Or, as one physician puts it, "just like the 'far, dark side of the Moon', which is invisible from the earth, the mucosal response to pathogens is a far, dark side of immunity that is poorly or not visible from the peripheral blood and more complicated to probe than systemic immunity."
What's the best way to elicit mucosal immunity?
TBD. Different groups are trying a variety of strategies. The goal is to induce immunity in the airways that is robust, broad, and durable. But which strategy will succeed is a bit of a question mark at the moment. Mucosal vaccines fall into a few categories depending on how they're administered and the platform they use. Some are sprays that are squirted into the nose (CovLiv, for example). Others are meant to be inhaled into the lungs (such as one developed by CanSinBIO in China).
Sometimes these two routes of administration get lumped together, but they actually are very different, says Mangalakumari Jeyanathan, a researcher at McMaster University and coauthor of an editorial that accompanies the new inhalable-vaccine paper. With a nasal vaccine, the contents go into the nasal cavity. But Jeyanathan thinks inhaled vaccines, which go deep into the lungs, are likely to work better. Her team's research suggests that nasal vaccines induce immune responses only in the upper respiratory tract, not in the lower respiratory tract. That means, she says, that if the vaccine doesn't prevent infection, the lungs are still vulnerable, and "we really need the immune responses to prevent any sort of serious damage to the lung."
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