The early numbers on levels of COVID-19 antibodies found in public samplings are all over the map, and await more rigorous random sampling before they can tell us much about how infectious this virus really is, or about potential immunity. However, there are a few important things we HAVE learned from the early testing for antibodies.
The first is that COVID-19 will be with us for a long time. The Chinese just released a study which indicates we will likely have to contend with recurring waves of the virus until we have medicines and/or vaccines scaled up to match the level of asymptomatic infected people who are unknowingly infecting susceptible people. In scientific studies, the virus appears to start shedding 2 days after exposure and 1-3 days before symptoms appear, and it continues to shed up to 42 days (highest number I have seen) after symptoms subside.
Based on modeling the closest relatives to COVID, MERS and SARS, we anticipate approximately 6 waves of the virus over the next 18 months. We will be having to modulate our economy continuously during this period, as we clamp down to (somewhat) control the virus, then let up to (somewhat) rescue the economy, repeatedly. There will be a lot of hard choices in this period for governments, businesses, institutions, and individuals. As we increase testing density, our decision making and response will improve.