Nov 5 (Reuters) - Pfizer Inc (PFE.N) is in discussions with 90 countries over supply contracts for its experimental COVID-19 pill, which was shown to reduce by 89% the risk of hospitalization or death in patients at high risk of severe illness, Chief Executive Officer Albert Bourla said in an interview on Friday. He said Pfizer expects to price its treatment, called Paxlovid, close to where rival Merck & Co Inc (MRK.N) has priced its oral antiviral drug candidate. Merck"s U.S. contract price for its pill molnupiriavr is around $700 for a five-day course of therapy.