The challenges for Congress in confronting a renewed domestic threat of measles seem like an unfortunate case of déjà vu to a former lawmaker who had great influence on the American health care system in recent decades.

Henry A. Waxman, a California Democrat who was chairman of the Oversight and Government Reform and Energy and Commerce committees while he was in the House, repeatedly defended the government program to have vaccines readily available to counter once routine infections that could be life threatening. The World Health Organization estimates immunizations now prevent 2 million to 3 million deaths a year, holding in check infections such as diphtheria, tetanus, pertussis and measles that disproportionately affect children.

“Every time an ideology popped up to threaten the immunization programs in this nation, what we had, fortunately, was enough reasonable people, Democrats and Republicans, who were able to put the needs of our children and their health above ideology and partisanship,” Waxman said at a Feb. 9 conference at Johns Hopkins University on the new threat of measles.

Lawmakers are again looking for ways to bolster public confidence in vaccines. Decisions by some parents to withhold vaccines from children healthy enough to get them has helped bring back measles in the United States, which had declared the infection virtually eliminated in 2000. So far this year, more than 120 people have been sickened by measles and doctors worry about its further spread.

In the House, there’s already a bid underway for more public transparency about how the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices makes its recommendations, a step that could ease some parents’ concerns. This is a provision in a bill Republican Rep. Renee Ellmers introduced with fellow North Carolinian G.K. Butterfield, a Democrat. It’s intended to be part of the Energy and Commerce Committee’s planned overhaul of medical regulation, known as the Cures package.

In the Senate, Health, Energy, Labor and Pensions Chairman Lamar Alexander, R-Tenn., and ranking Democrat Patty Murray of Washington jointly invited witnesses to a Feb. 10 hearing about increasing the use of vaccines in the United States. Senators there urged federal health officials to do more to overcome the resistance of some parents to vaccines, arguing for increased public awareness of the risks to children from measles. Often dismissed as harmless, measles used to kill about 1 in 1,000 children infected with it, and can cause complications such as deafness.

“I believe that the solution to misinformation is more information, and that it be science and evidence based,” Sen. Barbara A. Mikulski, D-Md., told Anne Schuchat, director of the CDC’s National Center for Immunization and Respiratory Disease.

Fighting Old Battles

Senators expressed a frustration common to health policy experts these days. At the same time the Gates Foundation-backed “Decades of the Vaccines” campaign is trying to ensure immunizations are available in even the poorest countries, which could save more than 20 million lives, resources are being diverted in one of the richest nations to refight battles against measles.

Local health agencies must now trace contacts made by infected people, and federal officials have to develop strategies to contain its spread. Alexander chided parents for “turning away from sound science” on vaccines.

“At a time when we are standing on the cusp of medical breakthroughs never imagined — cutting-edge personalized medicine tailored to an individual’s genome, for example — we find ourselves retreading old ground,” he said.

There are strong parallels with a situation Waxman faced in the 1980s.

Concerns about potential neurological harm from a childhood vaccine persisted despite studies that found no such a link. The issue then was the immunization for the pertussis bacteria, which triggers a characteristic hard whooping cough and can particularly threaten infants.

Waxman and colleagues such as Sen. Orrin G. Hatch, R-Utah, pulled together the National Childhood Vaccine Injury Act, passed in 1986 as part of a larger health care package. It is best known for creating the National Vaccine Injury Compensation Program. It was meant to serve as an alternative to lawsuits for what are considered rare cases when immunizations injure patients.

The law also instructed the Institute of Medicine to study reports of injuries linked to vaccines. The institute has repeatedly studied the safety of vaccines and in 2011, reported that eight vaccines, include one for measles, are “generally very safe and that serious adverse events are quite rare,” according to a CDC summary of this work.

But a small group of parents still have doubts, which many scientists see as the echo of a 1998 article in the Lancet medical journal by Andrew Wakefield. Retracted by the Lancet in 2010 because of its flawed science, the article helped spark a backlash against the measles-mumps-rubella vaccine by saying it could cause autism. Wakefield gained great prominence among vaccine questioners, including then-House Oversight and Government Reform Chairman Dan Burton, R-Ind., who had Wakefield give testimony to the committee several times.

“Dr. Wakefield, like many scientists who blaze new trails, has been attacked by his own profession,” Burton said at a 2002 hearing.

Speculation about a connection between vaccines and autism persisted even after another famous article linking vaccines and autism was retracted by Salon. Rolling Stone, Salon’s partner in publishing the 2005 piece by Robert F. Kennedy Jr., also has made public its concerns about the article.

In recent weeks, two potential Republican presidential candidates — Sen. Rand Paul of Kentucky and New Jersey Gov. Chris Christie — have said parents might have reasons other than medical necessity, such as the case of a child suffering leukemia, for withholding vaccines from their children.

The Infectious Diseases Society of America is pressing for an end to the exemptions from vaccine requirements that now exist in some states for religious and personal beliefs, and says only medical ones should be allowed.

In Mississippi, where only medical exemptions are allowed, less than 1 percent of kindergartners were not fully immunized in the 2013-14 school year, according to the CDC. That figure is about 7 percent in Oregon and 6 percent in Idaho and Vermont, where religious and personal exemptions are allowed. Experts say the true worry is that the state average blends communities with relatively high compliance with pockets where even greater numbers of parents opt out.

The CDC’s Schuchat has called the immunization program a victim of its own success. Many parents have never seen measles, as state requirements for immunizations for kindergarten entrance had contained the infection for many years. In answering a question at a Feb. 3 House Energy and Commerce subcommittee hearing, Schuchat noted the warm embrace of what was seen as a revolutionary immunization in the 1950s for another disease.

“In that era, you didn’t need to mandate polio vaccine. People were lining up,” Schuchat said. “The whole country was so thrilled that there was a polio vaccine.”