“The Common Cold” is caused by a lot of things, some of which are coronaviruses, but most of which are rhinoviruses. According to a doctor of my acquaintance, you actually do become immune to some of them after you have them, and to other for a period of time, but there are so many, and they are indistinguishable symptomatically, that you can’t know that you had one coronavirus last year which you will never get again.
And two-year immunity is certainly something.
Look how rabies cases went to near-zero with a vaccine for domestic animals that confers immunity for a few years, and which we repeat every few years.
So we get a Covid-19 vaccine that has to be repeated every two or three years. I’d get it. I’d get it for my son.
And, actually, a vet I had in the last city where I lived told me that many animals who lived to be elderly were found to have immunity to rabies that seemed to be permanent. Since it’s not legal not to vaccinate them, they have information only from the occasional necropsy on an old pet whose owner neglected vaccines after attending to them for years-- which happens-- if the animal gets arthritis, and is hard to get into the car, vet appointments fall off. Or if the animal gets cancer, some owners stop vaccinating. But some animals will live for five or six years with a slow-growing cancer (we had a dog like this, but we did vaccinate her; she was a big dog who lived to 15 & 1/2).
So a vaccine that must be repeated every year, or two years for 20 years, and then stopped, is possible. If you are 65, that could mean the rest of your life, but if you are 4, that means until the end of grad school. If you are a baby, it means until two years after high school-- a year before you can even legally drink.
Really, all bets are off.
Something that isn’t well known, is that while Jonas Salk developed the polio vaccine, and Paul Offit developed the current rotavirus vaccine, nearly every other childhood vaccine was developed by one person, a guy named Maurice Hilleman. So they are all similar in administration, and the way they work. That’s how he made vaccines. They were all developed during his active years, so with relatively similar technology, too.
But vaccines don’t have to work the way we are familiar with. Actually, Hilleman did vary his methods, in that when he couldn’t get immunity to a killed virus, he would try an attenuated virus, then just the protein coating on a virus, when it had one. He did evolve, but he still was mostly one guy, working with some grad student assistants, but really sort of a cowboy. He actually made the mumps vaccine from a swab he took one evening from his daughter’s throat when she came down with the illness.
However, treatments can go in all sorts of directions. Hilleman saw a virus, and thought to make people immune with the virus itself, by disabling it some way.
And that’s how most lay people think when they think about a Covid-19 vaccine. But really, there may be some as-yet-unimagined way to fight it that will come up as the virus is studied.