UC Davis Health, Kaiser Permanente and other local health care systems are beginning to dispense the new Pfizer antiviral pill Paxlovid that has been shown to be highly effective against the omicron variant of COVID-19.
The drug is a “game-changer,” said Timothy W. Cutler, assistant chief of pharmacy for ambulatory clinical services at UC Davis Health, but right now, the nation’s supply of it is very limited. UC Davis’ physicians will be using a scoring system developed by the National Institutes of Health that outlines risk factors that determine a patient’s eligibility.
“It allows us to treat high risk patients and keep them at home for their treatment,” he said. “The new therapy will reduce the impact on the hospital and infusion center and allow treatment to occur where patients are most comfortable.”
High-risk patients include individuals with a compromised immune system, older age, and those with chronic illnesses that may put them at risk for hospitalization, UC Davis experts said. Liver transplant survivor David N. Frick, a professor of chemistry and biochemistry at the University of Wisconsin-Milwaukee, told the news service SciLine that antiviral drugs like Paxlovid and Merck’s Molnupiravir are crucial for immunosuppressed individuals like him.
“These are really to help people who don’t respond to the vaccine or people who aren’t protected by the vaccine,” Frick said, “and so in America we probably have almost a hundred million people like that. Right, either they’ve chosen not to get the vaccine, they can’t get it because they’re allergic, or they’re people like me who are immunosuppressed, and they just don’t respond to the vaccine....A lot of people who are immunosuppressed don’t make antibodies to protect themselves after they get the vaccine.”
The California Department of Public Health reported Wednesday that unvaccinated individuals are eight times more likely to get COVID-19 and 13 times more likely to be hospitalized with it than state residents who received vaccinations and a booster.
While vaccines can prevent the virus from overwhelming the body, these pills will cure or kill the virus, Cutler and other experts said, and in efficacy trials, both drugs were shown have the greatest effect when taken early. In the case of Paxlovid in particular, Cutler said, all studies were done within five days of the onset of patients’ symptoms.
Which drug is better?
Katherine Seley-Radtke, a professor of chemistry and biochemistry at University of Maryland, Baltimore County, said: “Molnupiravir is only about 30% effective against high-risk, unvaccinated patients, where Paxlovid has been shown to have 89% efficacy against unvaccinated, high-risk patients. So clearly, it looks like Paxlovid is much better.”
How do these antivirals work?
“Both of these drugs are what we call direct-acting antivirals, and those are drugs that essentially mess up the machines that a virus makes inside your cells so that the virus can replicate,” Frick said. “The Merck drug inhibits the machine that the virus uses to make its genome, which is made out of RNA. The Pfizer drug inhibits an enzyme called protease, and that’s an enzyme that the virus makes to cleave up its own little proteins so it can make it a functional machine. So they have different targets; they work differently.”
Where are the COVID-19 pills available?
UC Davis Health patients will be able to pick up Paxlovid at the UC Davis Pavilion Pharmacy, according to a news release from UC Davis, but plans are in the works to make it available at the group’s ambulatory care center and its Cypress pharmacies in the next couple of weeks.
A Kaiser spokesperson said physicians at the San Francisco Medical Center have begun dispensing the medication in coordination with patients and that other Kaiser Permanente medical centers will follow as they receive their allocation of inventory.
Physicians practicing with Sacramento-based Sutter Health and other local health care organizations also can prescribe Paxlovid to their high-risk patients fighting the respiratory disease at home, and the patients will have to pick them up at CVS or other retail pharmacies with a supply of the drug.
CVS spokesperson Monica Prinzing said each state selects which pharmacies can participate in the distribution and the federal government uses the state lists to determine distribution of the oral Pfizer and Merck antiviral COVID-19 therapies. CVS Pharmacy is a participating provider in 11 states, including California and Nevada, she said.
The U.S. Department of Health and Human services has a website listing pharmacies that are designated to dispense either Pfizer’s Paxlovid or Merck’s Molnupiravir antiviral pills. If users zoom in on the map until they see only their geographic area, they will see a list of sites showing which pill is available at various pharmacies and health care institutions. Regulators say consumers should not contact any listed site directly but instead work through their physicians to get access.
Are there any age or health restrictions?
While Molnupiravir is authorized for treating adults age 18 years and older, regulators said, Paxlovid can be prescribed to adult and pediatric patients age 12 years and older weighing at least 88 pounds. With Paxlovid, Cutler noted, patients must take a total of six pills per day — three in the morning and three in the evening — for 5 days.
People with moderate kidney problems would take fewer pills per day, Cutler said, and those with severe kidney problems cannot take it at all. It is crucial, Cutler added, that physicians know all drugs a patient is taking since there are a significant number of potential drug interactions with Paxlovid that could affect a patient’s health.