Does this mean that the 81% who have a T cell response are completely asymptomatic or that some are while others will just have a mild illness?

MikeT provided this link last week.

https://thorax.bmj.com/content/early...nl-2020-215091

This study found that 59% of people on a cruise ship tested positive for Covid-19. However, interestingly it also revealed that 81% of those people were asymptomatic. Perhaps, these people had T cells that could fight it off as above and would probably not be revealed to have had the virus in an antibody test.

Much is being made about the apparent explosion of new cases in the USA at the moment. However, the states that are showing the large increases appear to be those that got off relatively lightly early on in the pandemic, such as Texas. There is no such spike in New York, which as we all know was previously very badly affected.

Another example to look at is South Africa. It had one of the most stringent lockdowns in the world and early on too. South Africans weren't even allowed to buy alcohol or cigarettes. They successfully suppressed the virus throughout March, April and much of May. But much good it has done them now. As the lockdown has eased, cases are now rapidly growing.

I guess the point I'm getting to is does in the end the virus have to get to around 20% of the population, who don't have some sort of immunity and then after that it will naturally tail off of it's own accord? In which case, unless a vaccine comes along before this level is reached, is lockdown a waste of time? I don't know, but it seems possible.