Scientists believe a vaccine that doctors spray into the patient's nose would work better than a vaccine injected into the patient's veins. After a nasal vaccine, the body's immune cells look for the virus in the nose and mouth. The nose and mouth are where most people are infected with SARS-CoV-2. Scientists are not sure why this works. As of July 2020, teams in the Netherlands, the United States, and Canada are making nasal vaccines.