Canada on Monday announced it has authorized Pfizer's at-home coronavirus antiviral pill treatment for use by adults with mild to moderate COVID-19 symptoms who are at risk of serious disease that may result in hospitalization or death.

Health Canada said the medicine named Paxlovid is a combination of two antiviral drugs nirmatrelvir and ritonavir that are intended for use as soon as possible following a diagnosis of COVID-19 and within five days of symptoms arising.

"Until now, authorized medications for COVID-19 have had to be taken in a hospital or healthcare setting. Paxlovid is the first COVID-19 therapy that can be taken at home," Health Canada said in a statement.

Pfizer announced in November that its antiviral treatment was found during clinical trials to reduce risk of hospitalization and death by 89% compared to a placebo in non-hospitalized high-risk adults with COVID-19.

On Dec. 1, Health Canada received Pfizer's submission for authorization, and the pharmaceutical giant continued to submit data to Ottawa health officials on a rolling basis through the review process as new information became available "to facilitate a decision as quickly as possible," the government health body said.

Health Canada warns that while "the benefits of Paxlovid were found to outweigh the risks," it can cause issues when taken with other medications for some patients, and it is advising for people to discuss the risks and benefits of the treatment with their healthcare providers.

"As our healthcare system and hospitals face significant pressures in this ongoing pandemic, this new treatment will provide a new option in the management of COVID-19," Kevin Mohamed, Pfizer Canada Hospital Business Unit lead, said in a statement. "Pfizer is ready to begin delivery in Canada immediately to help get Paxlovid into the hands of appropriate patients as quickly as possible."

Ottawa in December had entered an agreement with Pfizer for 1 million treatments of Paxlovid to be delivered throughout the year.

Canada follows the European Union granting the drug's use as it starts a rolling review of the data on Dec. 16 and the United States authorizing it for emergency use on Dec. 22.

On Jan. 4, Pfizer announced the United States had agreed to purchase from it an additional 10 million treatment courses of Paxlovid, which is on top of the previous 10 million originally contracted by the Biden administration.

The first shipment of 10 million treatments are to be delivered by the end of June with the remaining pills to follow by the end of September.

"With data showing significant reductions in hospitalizations and deaths, along with the potential for Paxlovid to maintain robust antiviral activity against Omicron, we believe this therapy will be an important tool in the fight against COVID-19," Albert Bourla, chairman and chief executive of Pfizer, said.

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