An influential advisory committee has given only lukewarm support to a government recommendation that all baby boomers be tested for hepatitis C.
In a draft opinion Monday, the United States Preventive Services Task Force said that clinicians may “consider offering” hepatitis C screening to adults born between 1945 and 1965.
That falls short of the recommendation made in August by the Centers for Disease Control and Prevention that all adults in that age group should get a one-time test to see if they are infected.
The task force is made up of outside experts appointed by the government, and its recommendations can in some cases carry more weight than those of the C.D.C. Had hepatitis C screening for baby boomers received a stronger recommendation from the task force, health plans would have been required to pay for it under the 2010 Affordable Care Act, with no charge to the patient.
Some advocates of wider screening said they feared the new opinion would be used by insurers to deny reimbursement for testing and would slow efforts to ferret out hidden cases of hepatitis C at a time when more effective and tolerable treatments are being developed.
The recommendation “could derail the hard work that the C.D.C. has put in in proving the case that it’s smart for baby boomers to get a one-time hepatitis C test,” said Martha B. Saly, director of the National Viral Hepatitis Roundtable, a coalition of more than 200 groups dedicated to eradicating hepatitis. Some drug companies, which would benefit from wider screening, are associate members of the round table.
Dr. Kirsten Bibbins-Domingo, of the University of California, San Francisco, and a member of the task force, said differences in the recommendations were merely a matter of degree. “I would say our findings are compatible,” she said.
The C.D.C. declined to comment, saying the opinion was still a draft.
About 3 million Americans are infected with hepatitis C, but 45 percent to 85 percent of them do not know it, according to the C.D.C. The virus can cause scarring of the liver and liver cancer, though typically not until decades after the initial infection, and not in everyone. About 15,000 people a year die from hepatitis C.
The C.D.C. used to recommend screening only for people most likely to be infected: intravenous drug users or people who got blood transfusions before 1992 when testing of donated blood for the virus began.
But a lot of cases were missed because people did not remember risky behaviors from decades ago or did not tell their doctors.
So in August the C.D.C. recommended that all baby boomers be tested. Although only about 3 percent of this age group is infected, they account for about three quarters of all cases. Screening them would detect more than 800,000 infections, which could then potentially be treated, averting many cases of liver disease and about 120,000 deaths.
But the task force said there were no clinical trials or studies directly proving that screening asymptomatic adults would reduce liver disease or deaths.
It noted that the C.D.C. recommendation was based partly on computer models that might have overestimated how many people with hepatitis C would develop liver cirrhosis or die, and therefore overstated the number of cases or deaths that could be prevented.
The task force concluded that there would be at least a small benefit from screening baby boomers and gave the recommendation a grade of C, meaning “for most individuals without signs or symptoms there is likely to be only a small benefit from this service.”
The task force provoked controversy in the past with recommendations against screening for prostate cancer and against routine mammograms for women under 50.
In 2004, the task force recommended against hepatitis C screening of adults not considered at high risk.
The draft, posted on the task force Web site, will be open for comment until Dec. 24. The evidence behind the recommendation is being published in The Annals of Internal Medicine.