If we are blithely ignorant now of rates of Covid-19 infection, it’s largely thanks to vaccines, which kept most people free from serious illness. But the immune defenses we get from vaccines and from infection wane in time. Disease in circulation means the new variants and subvariants are likely, with no guarantee that they will be weaker or less transmissible than previous iterations.
The question for next winter and beyond is whether and how we’ll keep revaccinating the population. The White House convened scientists, doctors and researchers Tuesday to talk about next-generation vaccines. One option that has many excited are nasal spray vaccines, but there is also reason for caution.