With an increase in COVID-19 measures, several counties in the Chicago area have entered a “high” alert level under guidelines set by the Centers for Disease Control and Prevention.
And, according to the CDC, a new omicron subvariant is the dominant strain of COVID in the United States, with BA.2.12.1 responsible for nearly 59% of new cases over the past week.
As more cases are reported and the disease continues to spread, many are asking about Pfizer’s new COVID-19 antiviral pill Paxlovid.
Paxlovid has been used in several recent high-profile cases, including that of Vice President Kamala Harris.
As doctors continue to prescribe the drug, new questions are emerging about its side effects, why a small number of patients seem to relapse and more.
Here’s what we know so far.
What are the side effects of Paxlovid?
According to Pfizer, the possible side effects of Paxlovid are:
- Allergic reactions. Those who experience a reaction are urged to stop taking Paxlovid and call a health care provider. Symptoms of an allergic reaction include:
- difficulty swallowing or breathing
- swelling of the mouth, lips, or face
- throat tightness
- itchy skin
- Liver problems. Symptoms of liver problems such as loss of appetite, yellowing of the skin and whites of the eyes (jaundice), dark urine, pale stools, and itchy skin or pain in the stomach area ( abdomen) are possible. Pfizer urged anyone with these symptoms to contact their doctor as soon as possible.
- Resistance to anti-HIV drugs. Use of the drug may lead to some HIV medications not working as well in the future in people with untreated HIV infection.
- Taste alteration
- High blood pressure
- Muscle aches
Pfizer warned that additional side effects could also be possible.
Who is eligible to take the pill?
Paxlovid has been approved for emergency use in people 12 years of age and older, weighing at least 88 pounds, and at high risk of progression to serious disease. The pill must be prescribed by a doctor.
“Patients in the licensed population with a risk factor for progression to severe COVID-19 are eligible for Paxlovid under EUA even if fully vaccinated,” the FDA said. “Patients need not have more than one risk factor to be considered ‘high risk’.”
If I tested positive for COVID and took Paxlovid, do I still need to self-quarantine?
According to Chicago Department of Public Health Commissioner Dr. Allison Arwady, the CDC’s 10-day quarantine period applies to those who test positive for COVID, whether the five-day course of Paxlovid was taken or nope.
“So remember, this is all in this same 10-day window and we want you to self-isolate, we want you to stay home, while you have symptoms in this window,” Dr Arwady said in a Facebook Live on Tuesday, in reference to patients who took the drug.
“So if you’re someone who – although it doesn’t happen that often – if you take Paxlovid and you feel fine, and your symptoms get a bit worse…you should stay home. until you know until you feel better and obviously keep in touch with your doctor.”
How many doses do you need if you are taking the pill?
Paxlovid consists of three pills taken twice a day for five days.
How effective is the pill and what do we know about patients who relapse?
Experts say there is still much to learn about the drug, which was approved in December for adults at high risk of severe COVID-19 based on a study in which 1,000 adults received the drug.
Doctors have started reporting rare cases of patients whose symptoms return several days after completing the five-day regimen of Paxlovid pills. This has raised questions about whether these patients are still infectious and should receive a second treatment.
Last month, the Food and Drug Administration weighed in, advising against a second round because there is little risk of serious illness or hospitalization in patients who relapse.
Dr Michael Charness reported last month on a 71-year-old vaccinated patient who saw his symptoms improve and then come back, along with virus levels peaking nine days after his illness began.
Charness says Paxlovid remains a very effective drug, but wonders if it might be less potent against the current omicron variant. The $500 drug treatment has been tested and approved based on its performance against the delta version of the coronavirus.
“The ability to clear the virus after it’s suppressed may be different from omicron to delta, especially for vaccinated people,” said Charness, who works for Boston’s VA Health System.
Could some people just be susceptible to relapse?
The FDA and Pfizer point out that 1-2% of people in Pfizer’s original study saw their virus levels rebound after 10 days. The rate was about the same in people taking the drug or the dummy pills, “so it’s not clear at this point whether this is related to the drug treatment,” the FDA said.
Some experts suggest another possibility: the dose of Paxlovid is not strong enough to completely suppress the virus. Andy Pekosz of Johns Hopkins University is concerned about what could stimulate drug-resistant mutations.
“We really should make sure we dose Paxlovid appropriately because I would hate to lose it right now,” said Pekosz, a virologist. “It’s one of the essential tools we have to help us turn the corner on the pandemic.”
Does Paxlovid work in vaccinated people?
Pfizer tested Paxlovid in patients most at risk: unvaccinated adults with no previous COVID-19 infection and no other health conditions, such as heart disease and diabetes. The drug reduced their risk of hospitalization and death from 7% to 1%.
But that doesn’t reflect the vast majority of Americans today, where 89% of adults have had at least one injection. And about 60% of Americans have been infected with the virus at some point.
“That’s the population I care about in 2022 because that’s who we’re seeing — people vaccinated against COVID — are they benefiting then?” asked Dr. David Boulware, a researcher and physician at the University of Minnesota.
There’s no clear answer yet for vaccinated Americans, who already have a hospitalization rate well below 1%.
This may stem from a large, ongoing Pfizer study that includes high-risk vaccinated people. No results have been published; the study is expected to be completed in the fall.
Pfizer said last year that early results showed Paxlovid failed to meet study goals of significantly resolving symptoms and reducing hospitalizations. It recently stopped enrolling anyone who received a vaccine or booster in the past year, a change Boulware says suggests those patients are not benefiting.
At a minimum, preliminary data should be shared with federal officials, Boulware said. “If the US government is spending billions of dollars on this drug, what is the obligation to publish this data so that it can formulate good policy?”
Can the pill be used to prevent COVID infection?
Pfizer recently reported that proactively giving Paxlovid to family members of people infected with COVID-19 did not significantly reduce their chances of catching it. But that’s not the end of the story. Pfizer is investigating several other potential benefits of early use, including whether Paxlovid reduces the duration and severity of COVID-19 in households.
“It’s a high bar for protecting against infection, but I’d like to see data on how Paxlovid did against serious illnesses because it may be more effective there,” Pekosz said.