The resurgence of measles across the United States is spurring a backlash against vaccine critics, from congressional hearings probing the spread of vaccine misinformation to state measures that would make it harder for parents to opt out of immunising their children.
In Washington state, where the worst measles outbreak in more than two decades has sickened nearly 70 people and cost over US$1 million, two measures are advancing through the state legislature that would bar parents from using personal or philosophical exemptions to avoid immunising their school-age children. Both have bipartisan support despite strong anti-vaccination sentiment in parts of the state.
In Arizona, Iowa and Minnesota, lawmakers have for the first time introduced similar measures. The efforts have sparked an emotional, sometimes ugly response from those protesting what they see as efforts to trample on their rights. Opponents of the Arizona bill, which died quickly, have described the toll of stricter vaccine requirements as a Holocaust and likened the bill's sponsor, who is Jewish, to a Nazi.
In Vermont, legislators are trying to do away with the state's religious exemption four years after eliminating the philosophical exemption. In New Jersey, where lawmakers have sought unsuccessfully to tighten religious exemptions, a bill to repeal it entirely was recently amended on the General Assembly floor.
While it's too early in the legislative season to say how many of the state efforts to tighten vaccine exemptions will be signed into law, some public health advocates say the rash of vaccine-preventable illnesses is creating a shift in public thinking.
"The wave is starting to turn back," said Michelle Mello, a professor of law and health research and policy at Stanford University.
Diane Peterson of the Immunisation Action Coalition, a Minnesota nonprofit group, said that "there is a growing consensus for state authorities to make the bold move to require all children to be vaccinated, with the only exception being those who cannot be given the vaccine for medical reasons."
Amid mounting public pressure, websites that have been a platform for the anti-vaccination movement's misleading claims are also making changes. Pinterest has blocked all searches on vaccinations to stop the spread of misinformation, while Facebook is considering removing anti-vaccination content from its recommendations. YouTube said it is also pulling ads from anti-vaccine videos, claiming they violate its policies against "harmful or dangerous" acts.
The US House and Senate have scheduled rare bipartisan hearings this week and next to investigate the reasons behind recent outbreaks.
"If vaccine hesitancy persists - or even expands - it could seriously undermine these important advances," Sens. Lamar Alexander, R-Tenn., and Patty Murray, D-Wash., - the Senate Health, Education, Labour and Pensions Committee's chairman and ranking Democrat - wrote to federal health officials.
All those actions are happening against a backdrop of rising global concern about vaccine hesitancy as cases of measles have surged because of gaps in vaccination coverage. For the first time, the World Health Organisation listed vaccine hesitancy as one of the top 10 global threats of 2019.
No measles deaths have been reported in the United States since January 1, but the virus can be deadly, especially for children. Nearly 1,000 people, mostly children, have died of the illness in Madagascar this year, according to the WHO, offering a window into how rapidly the disease can devastate a country with low vaccination rates.
In Europe, measles cases are at a 20-year high, with 60,000 cases and 72 deaths. A quarter of those are in Italy, where anti-vaccine groups allied with populist politicians won passage last year of a law to end compulsory vaccines - a law repealed a short time later because of soaring measles cases.
Such fears are not going away soon.
The introduction of competing anti-vaccine bills in state legislatures reflect continuing alarm about vaccine safety, said Barbara Loe Fisher, who heads one of the oldest and best-established anti-vaccine groups, the National Vaccine Information Center.
"You cannot bring down the hammer on people and force them to obey one size fits all when the risk is not being shared equally," she said, adding that individuals have different genetic risks.
She argues that parents should have the right to make voluntary decisions without their children being denied a school education. "We consider this to be parental rights, a human rights issue," Fisher said.
While 11 states are considering bills to restrict or eliminate vaccine exemptions, her group supports 60 out of 141 vaccine-related state measures, "which is the most bills we have supported in a legislative session," she said.
Groups such as Fisher's frame their message in terms of individual rights, insisting that parents, not the government, should decide whether to vaccinate their children - an argument championed by affluent, well-educated parents that resonates with liberals and conservatives.
Those responsible for protecting public health counter that immunizations are designed to protect whole communities, not just individuals - especially those community members who cannot get the shots, such as young children, pregnant women and those with compromised immune systems. When immunisation rates fall below a certain level - between 93 per cent and 95 per cent for measles - the vulnerable are at much higher risk. It is a rationale that has repeatedly persuaded judges to uphold mandatory vaccination programs.
And the enforcement of such mandates resulted in the elimination of measles from the United States in 2000.
As public memory of the terror of measles epidemics has faded, however, doubts about vaccines have grown - often stoked by debunked assertions linking the shots to autism. Between 2009 and 2013, the use of nonmedical exemptions for kindergartners increased by 19 per cent nationwide, according to a 2014 study.
That created pockets such as the one in Clark County, the epicenter of Washington state's outbreak, where rates fell far below the threshold needed to create community immunity.
Since this year began, there have been 159 measles cases reported in the United States - more than the total reported for all of 2017, according to data from the Centers of Disease Control and Prevention. All are linked to travelers who brought measles back from other countries, such as Israel and Ukraine.
New York has been scrambling to contain its largest measles outbreak in decades, with more than 200 people sickened since it's start in October. Texas is grappling with an outbreak that has infected nine people, including four in Harris County, which includes Houston.
After the measles outbreak prompted Governor Jay Inslee, a Democrat, to declare a state of emergency in Washington state, the Portland, Oregon, school where Rachel Hall's son is a kindergartner told students, staff members and parents without immunity to measlesthat they would probably be required to stay home for two to three weeks if a measles case were confirmed there. The school has a high number of unvaccinated children.
Hall had hesitated to give her first child the shots. "I was attempting to do the natural-birth, hippie-dippie thing," she said. But she has since immunized both her children.
Still, measures to impose stricter vaccine requirements draw fierce opposition. In Washington, nearly 1,000 people turned out for the public hearing last week on a state Senate bill that would eliminate all personal exemptions for all vaccines. Most were opposed to the bill.
Jill Collier, a registered nurse, told lawmakers she was against the bill because she believed it would harm the doctor-patient relationship. "We cannot blanket-mandate an injection for a child and hold their education hostage for noncompliance," she said.
The bill's sponsor, state Senator Annette Cleveland, a Democrat whose district is at the epicenter of the outbreak, said the measure would reduce the threat of exposure by 75 per cent.
"I don't know how we've come to a point today where we no longer continue to embrace the miracle that vaccines continue to be in eradicating disease," Cleveland said in an interview.
Anti-vaccine narratives do particularly well on social media because personal anecdotes and sensational content play better than the dry recitation of scientific facts, according to a study last year. Although anti-vaccine proponents are a small minority, on social media they may appear to be the majority.
And anti-vaccine activists are learning to leverage their strength in the public square as well. Increasing numbers have appeared at public meetings of a national vaccine advisory group, called the Advisory Committee on Immunization Practices, which makes recommendations to the CDC and meets three times a year in Atlanta.
The Facebook page of a recently formed group, Inundate the CDC ACIP, posted a photo of nearly two dozen people at the October meeting above the caption "Vaccine Truth Warriors descend on the CDC ACIP meeting."
Lynette Marie Barron, who manages the Facebook page, said she started it as a way to give voice to parents like herself who claim their children have been injured by vaccines.
"We want to bring them the stories and the science they refuse to look at," said Barron, 38, of Pell City, Ala.
More than 400 people have registered to attend the immunisation panel's next meeting, on Wednesday.