 We just passed four million total confirmed cases and over 145,000 deaths, but those confirmed cases really only tell part of the story, since we know that cases and deaths are undercounted due to lack of testing, particularly at the beginning of the pandemic when only those with significant illness were tested and there were shortages and problems with So, you know, we know that there is a significant amount of asymptomatic spread that isn't captured in those testing numbers, particularly in places that still lack access to widespread testing. Testing is the foundation of a modern public health approach to controlling a virus. So, we have lots of tools in our toolkit, but at the very foundation is testing. So, is this surprising? No, because we've had problems with our testing from the very, very beginning and we're playing catch-up and we continue to be playing catch-up to try to really get an understanding of where we are and then we can go and use contact tracing to really limit the spread, but we can do better and we need to do better. It remains that many cases are mild and are not severe enough to be hospitalized or cause severe illness and of course that's a good thing. The flip side of that is the spread. So, if there are mild or asymptomatic cases that and people don't know that they're sick, then that's contributing to spread, which is if not identified then that keeps us in this situation even longer where we're not containing the spread. Achieving herd immunity varies by disease. For what we know about SARS-CoV-2, the virus that causes COVID-19, it's estimated to be about 60 to 70% of the population would need to be infected and have antibodies in order to reach herd immunity and that's based on the basic are not reproductive number, which indicates the average number of new people that a single infected person can expose and infect. For context, the flu is about 1.3, coronavirus is between 2 and 3, meaning it's a highly contagious disease. So, even at the higher end of the estimates of what we expect the true number of cases to be, we're still, the majority of the country is susceptible. We're still less than 5% of the population is infected. So, what does it take in order to reach that herd immunity? It's going to take a vaccine. What the vaccine would, if it passes the safety and efficacy trials and is considered a success, what this would mean is that people can have access to a vaccine that will be able to create immunity and prevent spread. Now, it's also very likely, as we're learning about immunity and length of immunity, that this vaccine would likely have to be annual, similar to the way that the flu vaccine is an annual vaccine. But this remains to be seen.