The Seattle flu study is an example of what you want. As https://komonews.com/news/coronavirus/seattle-flu-study-allegedly-tested-samples-for-covid-19-against-

The Seattle flu study is an example of what you want. As https://komonews.com/news/coronavirus/seattle-flu-study-allegedly-tested-samples-for-covid-19-against-federal-state-guidelines https://komonews.com/news/coronavirus/seattle-flu-study-alle... shows, the USA was refusing to test Americans in Seattle while COVID-19 was actually spreading. When the Seattle flu study tested they found that it had already been locally spreading for weeks. And in fact most people who think that they have COVID-19 in the USA are unable to verify whether or not they have it.