That latter term (ectopic lymphoid structure) comes up in connection with persistent inflammation where the immune system sets up camp near the problem point. Is this good or bad? Do these go away once the infection clears up?

I wonder if the vaccine causes inflammatory and other unpleasant responses when administered. If so, I wonder if those responses go away after the last dose, when the three months of protection begin.

Here are the two paragraphs that I found interesting:

> The new vaccine, for now known as GLA-3M-052-LS+OVA, mimics the T cell signals that directly stimulate innate immune cells in the lungs. It also contains a harmless antigen, an egg protein called ovalbumin or OVA, which recruits T cells into the lungs to maintain the innate response for weeks to months.

> In the study, mice were given a drop of the vaccine in their noses. Some recieved multiple doses, given a week apart. Each mouse was then exposed to one type of respiratory virus. With three doses of the vaccine, mice were protected against SARS-CoV-2 and other coronaviruses for at least three months.

A new area of research has opened up. This approach may be more useful for treatment than prevention. It's not really a vaccine; it's more like an induced vaccine response. Keeping the immune system in that state full time might be a problem. But after an infection, that's what's wanted.