How does Pfizer's COVID-19 pill work and who will get it?
CBC
This story idea came from audience members, like you, who got in touch with us. Send us all of your questions about COVID-19. We are listening: ask@cbc.ca.
Now that Health Canada has approved Pfizer's COVID-19 therapeutic Paxlovid for use in people 18 and older, CBC News has been receiving questions about how it works and what its limitations are.
For starters, it's an oral antiviral treatment. In other words, pills that help you fight off the symptoms of COVID-19.
But here's a closer look at the ins and outs of the treatment.
Paxlovid consists of two antiviral drugs packaged together: nirmatrelvir and ritonavir.
Patients take three pills twice a day: two of nirmatrelvir and one of ritonavir. In total, the full course of treatment requires you take 30 pills over the span of five days.
Nirmatrelvir is a new drug developed by Pfizer-BioNTech, while ritonavir is an existing drug often used in the treatment of HIV/AIDS.
The two drugs work together, health experts say. Nirmatrelvir does the heavy lifting by hacking the virus's ability to replicate and multiply, while ritonavir acts as a sidekick to nirmatrelvir, enabling it to remain in the body longer.
Paxlovid is something called a protease inhibitor, explained Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital.
"It stops the virus from dividing by blocking a part of its life cycle," he said, noting this allows your immune system to fight off the virus a lot easier.
But it's crucial to start treatment soon after infection, Bogoch said, "to really nip it in the bud early."
According to immunologist Dr. David Burt, who is also a member of Toronto's Black Scientists' Task Force on Vaccine Equity, the only drawback with these types of treatments is a "very narrow window of opportunity" before the drug loses its effectiveness.
When taken within five days of infection, Pfizer's clinical trials showed that the drug reduced risk of hospitalization or death by 85 per cent.
Canadians will need a prescription to get Paxlovid, according to Health Canada.
This story is part of CBC Health's Second Opinion, a weekly analysis of health and medical science news emailed to subscribers on Saturday mornings. If you haven't subscribed yet, you can do that by clicking here.
Lac La Ronge Indian Band's Woodland Wellness Centre has received funding to start a mobile addictions outreach program to address the opioid and mental health crisis.
Adriana Avelina Ruíz Márquez uses fake eyelash glue to attach a tiny transmitter to the thorax, just behind the head, of the monarch butterfly.
After several delays to the mission that will take four astronauts around the moon, NASA held a press conference today announcing that Artemis II is on track to launch as early as April 1.
Snuneymuxw First Nation is calling for a temporary closure and environmental investigation of a hazardous waste services company following a January oil spill on Duke Point near Nanaimo, B.C.
In February, five people were killed in separate avalanches across B.C. and Alberta. That same month, more than a dozen people were killed in California and Utah, including a particularly deadly avalanche that claimed the lives of nine. In Europe, from Andorra to Slovakia, the season has recorded 125 deaths from avalanches so far.
Getting a proper vehicle to transport people for urgent medical care is an ongoing challenge in fly-in First Nations in northwestern Ontario.
A new supergroup of musicians from Six Nations of the Grand River and Mississaugas of the Credit First Nation have collaborated on a Robbie Robertson-inspired song they will perform at the Junos Honouring Ceremony later this month in Hamilton.
People as young as 45 should be invited to provincial and territorial programs to screen for colorectal cancer, the Canadian Cancer Society urged on Wednesday.
The Métis Nation-Saskatchewan (MN-S) has opened an office and retail space in Ottawa to create a stronger presence in the capital since removing itself from the Métis National Council in 2024.
Toronto resident Winhan Wong's lung cancer journey began in 2016, with a nagging cough that just wouldn't go away.
Last month, Assembly of First Nations National Chief Cindy Woodhouse Nepinak pointed out on social media that history was made this year because there are a record 164 female chiefs serving across the country.
Most of humanity has a great propensity to think in the short-term, but generally, long-term considerations — air pollution, deforestation and emissions, for example — just aren't our thing.