If you haven't already seen it can I recommend the Chris Whitty Covid lecture on the Gresham College site which is available on the Gresham .college website (safe) .
He is an epidemiologist as well as chief medical officer , and he has some interesting things to say, comparing Covid 19 to other viral epidemics, talking about what governments can do when faced with an epidemic for which there is currently neither vaccine or cure. One of the things he emphasises is that currently(and for the foreseeable future) the only way to slow /control the disease is through reducing the level of infection person to person , it is vitally important that the R number, the formula used to calculate how fast infections spread , is kept at or under R1. Any higher and the infection is out of control. We don't know if previous infection gives any immunity, or if it does , for how long that immunity lasts, if we don't maintain social distancing and other measures we are in danger of not only having a second wave of infection of previously uninflected people but also the possibility that previously ill people will be reinfected. Since it now appears that the disease not only affects the lungs but in many hospitalised cases appears to cause immunalogical damage to other organs, particularly the kidneys, we would have issues of people requiring renal support as well as breathing support.
It is clear from the lecture that he and other epidemiologists fully expect a second wave, and furthermore expects that Covid 19 is going to be with us for a long time whether or not a viable , safe vaccine, or viable safe treatment drugs are developed which is not likely to happen within a year.
As he says, in the history of mankind we have only managed to completely remove one disease from the population. Other diseases are still with us, but often in mutated forms that we'd have immunity to, or in forms that are not easily transmitted. We don't know about Covid 19 and immunity, we do know it is easily transmitted.
Watch the lecture.