Boosting COVID Vaccines: From Muscles to Noses

You might have received a COVID-19 vaccine shot in your arm, but what about your nose? Scientists are exploring a new way to boost your immune system by giving a second vaccine dose through your nose. This two-step process starts with an initial shot in your muscle, like the vaccines you're already familiar with. The second dose, however, is given through your nose. This intranasal booster helps your body create more specialized antibodies in your mucous membranes, the first line of defense against respiratory viruses like COVID-19. In a study using mice, researchers found that this method rapidly increases both local and overall immune responses. They discovered that the nasal booster triggers a quick change in certain immune cells, turning them into IgA antibody producers. IgA antibodies are crucial for protecting your respiratory tract. Interestingly, these IgA-producing cells come from existing cells that were previously making another type of antibody, IgG. Moreover, clinical trials in humans showed that this two-step vaccination method also boosts systemic IgA antibodies, which can be found in your blood. This approach, using a vaccine enhanced with interferon, a type of signaling molecule, could be a promising strategy to rapidly and effectively protect you from respiratory viral infections.