Then after, for example, when the US and Europe begin to show the wave, we also retroactively tested the people who came in for the previous seven days, and found actually quite a few positive cases. Some of them are also retroactive.
Then after, for example, when the US and Europe begin to show the wave, we also retroactively tested the people who came in for the previous seven days, and found actually quite a few positive cases. Some of them are also retroactive.