Vaccines that are injected into arm muscles aren’t likely to be able to protect our nasal passages from marauding SARS-CoV-2 viruses for very long, even if they are doing a terrific job protecting lungs from the virus. If we want vaccines that protect our upper respiratory tracts, we may need products that are administered in the nose — intranasal vaccines.

Can they be made? Probably. Will they do what we want them to do, if they are made? Possibly. Is there still room for this type of next-generation product, given the record number of Covid vaccines that have already been put into use? Potentially. Will it be difficult to get them through development? Likely…

Intranasal vaccines have multiple advantages. They don’t require syringes, cutting the expense of vaccination and the amount of medical waste an immunization program generates. A vaccine that can be puffed up a nostril probably doesn’t require a health care professional to administer it; the oral polio vaccine used in many developing countries is dripped into the mouths of children by trained volunteers.

And intranasal vaccines are — in theory, anyway — easier to administer to children and people who have a phobia of needles. That said, O’Brien says in her experience as a pediatrician, children are not necessarily much more willing to take the nasally administered flu shot, FluMist, than a jab. “It doesn’t solve the delivery issues,” she said.