I think you mean Paxlovid? That's actually approved but apparently it's hard to make and Pfizer is still working on expanding production. Some pharmacies do have it however. As to highly effective, I believe it means that if you take Paxlovid you are very unlikely to need to be hospitalized and the length and severity of the infection will be significantly reduced. See this article for more info about someone's experience getting the drug.

https://www.nytimes.com/2022/01/19/business/covid-pill-treat...