(CNN) — The price of the lifesaving COVID-19 medication Paxlovid is likely to rise next year for most patients as the United States continues to transition out of the emergency phase of the pandemic, sparking concerns among doctors that it will become less accessible.

Just as with COVID-19 vaccines this season, the antiviral – a combination of the drugs nirmatrelvir and ritonavir – will move from being available free to everyone through government purchases to a more traditional commercial marketplace for most patients at the end of this year, according to the US Department of Health and Human Services and drugmaker Pfizer.

The new price – the cost before insurance – hasn’t been set but is expected to be higher than the $530-per-course price paid by the US government.

People who are on Medicare or Medicaid or who are uninsured will still be able to get Paxlovid for free through 2024 via a patient assistance program, according to HHS, but those with commercial insurance are likely to face a copay, Pfizer Chief Executive Albert Bourla said Monday. About 40% of prescriptions of Paxlovid are written for Medicare and Medicaid patients, he said.

“We are starting negotiations with payers,” Bourla told analysts and investors on a company conference call. The “pandemic price” paid by the US, he said, is likely to be “lesser” than the new commercial price.

One financial analyst who follows the company, Evercore ISI’s Umer Raffat, suggested that the price could go up three- to fivefold, to as much as $2,500 per course.

Dr. Eric Topol, a professor of molecular medicine at Scripps Research, called the potential plans for a price increase “more bad news of price gouging by Pfizer.”

“Less people who need Paxlovid will get it – whether it’s because of lack of insurance, or concerns about payment/co-pay,” Topol wrote in an email. “Even for those who have full coverage, sticking it to insurers just winds up, in the long run, increasing health care insurance premiums for all.”

Infectious disease physicians shared Topol’s concern about people’s ability to get the medication.

“There’s no doubt that cost is a major factor in determining access to medication in the United States,” said Dr. Paul Sax, clinical director of the Infectious Disease Clinic at Brigham and Women’s Hospital and a professor of medicine at Harvard Medical School. He noted that insurance plans vary widely in coverage and how much people have to pay out of pocket.

“The higher these costs are,” he said, “the more likely people are to forego treatment.”

A Pfizer spokesman said that the company plans to share information about pricing “in the coming weeks” and that “Paxlovid has and will continue to provide value to eligible patients, providers, and health care systems due to its important role in helping reduce COVID-19-related hospitalizations and deaths among people who are at high risk for progression to severe illness.”

Because the medication has been shown to reduce the risk of severe disease and death from COVID-19 among vulnerable groups, access is crucial even as the virus recedes from the forefront of everyday life, said Dr. Paul Offit, a professor of pediatrics in the Division of Infectious Diseases at Children’s Hospital of Philadelphia.

“This virus isn’t over,” he said, noting that it’s likely to circulate for decades. “Those who are at highest risk of severe illness need to make sure that if they have an upper respiratory tract infection that they test themselves, and if they’re positive very early on in the course of that illness, they need to take Paxlovid to save their life.”

Paxlovid is available by prescription and should be taken in the first five days of symptoms.

COVID-19 appears to be in a downturn in the US after hospital admissions related to the virus peaked in early September. Previous years have similarly seen increases in late summer, typically followed by larger waves around the end of the year. It’s not clear which pattern this winter will take, however.

Other serious respiratory viruses are just starting to pick up. Levels of respiratory syncytial virus, or RSV, appear to be low nationally but have picked up in the South, especially in Florida. Levels of flu were still low or minimal in all states except Alaska, where levels were moderate, in the first week of October, according to data from the US Centers for Disease Control and Prevention.

This season is the first with protection available against all three major respiratory viruses – flu, COVID and RSV – and the CDC recommends protection against all three for everyone who’s eligible.

Two RSV vaccines were approved this year for adults 60 and older, and an RSV vaccine was approved for use during pregnancy to protect babies early in life. A protective antibody shot for RSV was also approved for babies, which the CDC recommends for all up to 8 months old and for some older babies who are more vulnerable to severe disease.

An updated COVID-19 vaccine designed to protect against recently circulating strains is also available, and the CDC recommends it and the seasonal flu shot for everyone 6 months and older.

COVID-19 vaccines also increased in price once they stopped being provided universally by the US government. Shots from Pfizer, Moderna and Novavax were priced between $15 and $30 in large-volume purchase agreements with the government during the pandemic, and the companies increased the price about fourfold, to $115 to $130 per dose, after the US transitioned out of the system in which the government paid for the shots.

The vaccines are still supposed to be covered by insurance, but some people have been hit with out-of-pocket costs inappropriately in the early days of the fall rollout as insurance coverage through the commercial market settles into place.

Doctors fear that a higher price for Paxlovid could cause problems, as well.

“By making it more expensive, it just creates a huge hurdle,” Offit said. “Do I think that that will limit uptake? Yes, I do.”