Inhaled vaccines aim to target coronavirus at its point of invasion

The Covid-19 vaccines closest to the finish line are designed to be injected into the arm. Researchers are looking at whether they can get better protection from inoculations that fight the virus at its point of attack — the nose and mouth.

Most vaccines in human testing require two shots for effectiveness, and developers still aren’t even sure if they’ll prevent infections. Scientists are hoping to generate superior immune responses with inhaled vaccines that directly target the airway cells the virus invades.

An alternative to conventional jabs, sprayed and inhaled immunizations under development in the U.S., Britain and Hong Kong