Sarah Zhang writes a long article July 25, “A Vaccine Reality Check”, in the Atlantic (coronavirus coverage is free).
Most likely a vaccine will not be as effective as, say, measles, because this is a respiratory disease. It may require a booster, and be given every year.
It is likely that many vaccines will protect your internal organs and blood vessels but not stop the virus from colonizing in your nose and throat and being passed to others who aren’t vaccinated.
Also, the vaccine is likely to work only with people with normal or strong T-cell immunity, which forms a kind of “cloud backup” for neutralizing antibodies which disappear.
Some people seem to have a lot of latent or abstract immunity now with their T-cells. This may help explain the large number of totally asymptomatic cases.
Generally, when there is a mass spreading event, every one gets infected (like in a family). But members of a family cohort tend to react similarly; in some families no one gets sick but do test positive. Most professional athletes have few symptoms, but Freddie Freeman of the Atlanta Braves was quite ill and had a 104 fever.
Derek Thompson asks “How Long Does Covid Immunity Last?” The basic answer is, well, T-cells. Don’t become immunocompromised. Covid-19 is starting to act like a semi-opportunistic infection. (If you think about it, several of the OI’s associated with AIDS in the past could devastate multiple organ systems).
There is also a link to a big photoessay, “Coronavirus in Brazil”, by Alan Taylor, with people sewing masks and preparing mass graves for Bolsonaro’s “little flu”. (Picture above from Wikipedia, embed, click for attribution.)
On April 21, Connor Friedersdorf had written, “Let Volunteers Take the COVID Challenge”, young and healthy volunteers who would get infected deliberately if they got the placebo. There is a risk of a lifelong disability if something goes wrong.