A severe measles outbreak sickened dozens of Minnesotans last year and threw a harsh light on activists with vaccination concerns, but now they are back, believing they have gained the political clout to push through legislation that would alert parents to the rare but documented risks of vaccines.

At a forum for state legislators on Wednesday, leaders of the Vaccine Safety Council of Minnesota hope to persuade lawmakers to support an "informed consent" bill, which would require doctors to discuss risks with parents before vaccinating babies.

"There's been a shift in this country," said Jennifer Larson, a leader of the nonprofit council and an organization called Healthchoice that organized the forum. "I think it's tough for anyone to say more information is not better."

Larson said her group is not anti-vaccine; they believe consumers just need more upfront information about risks. But state health officials worry that opponents want to promote unproven claims that could unnecessarily scare people away from vaccinations.

With 79 confirmed cases, last year's measles outbreak was Minnesota's largest in 27 years, and falling vaccination rates in the state's Somali community played a role, said Kris Ehresmann, who directs vaccination programs for the state Health Department.

"Seventy-one of 79 were unvaccinated," she said. "It was very much an outbreak driven by lack of vaccination."

State records show that more than 90 percent of Minnesota children enter kindergarten vaccinated for infectious diseases such as tetanus, measles, hepatitis B, and chickenpox.

But survey data from the U.S. Centers for Disease Control and Prevention show a small decline in certain immunizations. And President Donald Trump proposed a safety commission to address vaccine concerns, though plans for that panel have stalled and the president didn't mention vaccines in his State of the Union address last week.

Public health officials also found themselves on the defensive after a report out of Australia late last year, while not related directly to pediatric immunizations, that found that the seasonal flu vaccine is only 10 percent protective. CDC estimates for the effectiveness of the flu vaccine between 2004 and 2017 ranged from a low of 10 percent to as high as 60 percent in any one flu season. The vaccine effectiveness fluctuates because the predominant flu strain is not the same each year.

Anxiety about the safety of vaccines has created an active coalition that includes some Minnesota refugee families, proponents of "natural" medicine, and parents who believe disabilities in their children can be traced back to shots they received.

Larson is the owner of an IT business and an autism treatment center, and recently was named finance chair of the Republican Party of Minnesota, though she stressed in an interview that the new role is separate from her advocacy on vaccines.

Larson said she took on the issues of vaccine administration and informed consent after her son, now 17, developed autism following his infant vaccinations.

"My son had a very clear reaction," she said.

The autism theory has bedeviled public health advocates, because no broadly accepted studies have proved a link between vaccines and the developmental disorder. Some who have claimed this link have been discredited. But the mere thought of a link has scared some parents into refusing or delaying vaccinations for their children, because autism is more alarming to them than diseases such as polio that largely have been eradicated by vaccination campaigns.

Larson said she believes health officials have exaggerated the safety of vaccines. She noted that the federal government's National Vaccine Injury Compensation Program has paid $3.8 billion since 1988 to people who claimed vaccine-related illnesses or reactions. "Parents want to be told everything before they inject something into their child," she said.

Speakers at the legislators' forum this week will include Del Bigtree, who directed "Vaxxed," a movie about a federal whistleblower who alleged that the government suppressed information about an autism link, and a Minneapolis woman who received federal compensation after she claimed that her son suffered a disabling reaction from the pertussis vaccine.

Larson supports legislation authored by state Rep. Cindy Pugh, R-Chanhassen, that would require doctors to disclose that neither they nor vaccine manufacturers are liable if they give shots that cause complications, and that scheduled combinations of vaccinations at single office visits haven't been studied for safety.

Pugh did not comment for this article.

Ehresmann said federal law already requires doctors to give "vaccine information statements" to parents, and the state checks to make sure pediatricians are doing so. The statements refer to vaccine risks and the compensation fund, but also the benefits of vaccine and the threats caused by the infections they target.

"These [vaccines] protect children against some serious diseases," said Ehresmann, recalling the case of a severe Hib (Haemophilus influenzae B) infection that occurred after parents delayed their child's shots.

The Minnesota Medical Association, which represents the state's doctors, opposes Pugh's bill, according to a spokesman, because it only requires vaccine-risk information that would discourage parents, and does not require information about the risks of children being unvaccinated.

Jeremy Olson • 612-673-7744