Israeli research has shown that the 7-day use of the antiviral drug Nirmatrelvir (Paxlovid) reduced more than 16-fold the risk of hospitalization due to Omicron infection in elderly patients over 65 years of age. However, administration of Paxlovid to younger people between 40 and 64 years of age did not reduce the risk of hospitalization. The paper published in NEJM.
https://www.nejm.org/doi/full/10.1056/NEJMoa2204919?query=featured_coronavirus