By Gary Evans, Medical Writer

In a year marked by more than 1,000 infections with a disease that once was eradicated in the United States, the tide of public opinion may be turning against the antivaccine movement.

As a record number of measles cases have spread to 30 states, science is starting to win the “vaccine wars,” said Paul Offit, MD, director of the Vaccine Education Center and an infectious disease physician at Children’s Hospital of Philadelphia.

“Frankly, it is hard to make a case that vaccines are evil in the midst of epidemics,” he said recently in Philadelphia at the annual meeting of the Association for Professionals in Infection Control and Epidemiology (APIC).

As of Aug. 1, 2019, there have been 1,172 measles cases in the United States this year, the CDC reports.1 That is the most cases since 1992, and makes a distant memory of the announcement in the year 2000 that measles had been eradicated in the United States — an accomplishment that was primarily due to childhood vaccinations.

Measles resurgence coincides with parents citing unsafe vaccines as a reason not to immunize their children. However, there is a growing pushback against the antivaccine movement, with herd immunity threatened and the real risk of measles to immunocompromised patients and those who cannot be immunized.

“These outbreaks — as awful as they are, as children have once again suffered a disease that is completely preventable — we are reaping some good from this,” Offit said. “Society is finally standing up for itself.”

In addition to several states acting to remove exemptions to childhood vaccines, there has been an accumulation of studies thoroughly debunking the claim that the measles-mumps-rubella (MMR) vaccine causes autism. One of the most recent was published this year, with researchers who investigated some 650,000 children in Denmark concluding that there is no link between vaccination and autism.2

“When you isolate the effect of that one variable — receipt of the MMR vaccine — there was no greater risk of developing autism if you got the vaccine or if you did not,” Offit said. “There are 18 studies now that have looked at that hypothesis. I would argue that this is one of the most tested hypotheses in the history of medicine. MMR vaccine does not cause autism.”

At times, public health attempts to accommodate and reassure those concerned about vaccines have been handled poorly, Offit said. For example, in the 1990s, attention turned to thimerosal, a preservative used primarily to prevent bacterial and fungal contamination of multidose vials of vaccines. To err on the side of caution, public health officials urged manufacturers to remove thimerosal from vaccines even though it posed no established threat, said Offit, who served on the CDC’s Advisory Committee on Immunization Practices (ACIP) at the time.

“This was done the wrong way,” he said. “We removed thimerosal in a precipitous and frightening manner.”

The CDC announcement of the move said there was no evidence the mercury levels in thimerosal in vaccines were harmful but pharmaceutical companies were urged to remove it “to make safe vaccines even safer,” he noted.

“Well, if it is not unsafe, then taking it out doesn’t make it safe,” Offit said. “It only makes it perceived to be safe, which is a very different thing. We scared people the way that we did this. We somehow felt that a tenet of risk communication was the compulsion to describe all theoretical risk, and it was done wrongly. In any case, because that was done, it really gave birth to several antivaccine groups.”

Hospital Infection Control & Prevention asked another national vaccine expert and long-time member of ACIP to weigh in on the thimerosal decision.

“It continues to be debated as to how wise or unwise that decision was,” says William Schaffner, MD, professor of preventive medicine at Vanderbilt University in Nashville.

The antivaccine movement saw the move in part as some kind of a concession, saying “they wouldn’t have done that unless there was a reason for it,” Schaffner recalls.

“The reason for it was to provide some calm,” he adds. “[With the thinking being] we will henceforth make single doses without preservatives and that should keep everybody happy, even though it wasn’t a problem before. I think that remains an unresolved conundrum.”

While the science now is undisputed in the medical community regarding the MMR vaccine and autism, many in the vaccine movement likely will hold to their beliefs and suspicions, Schaffner says.

“There has been a certain turnaround in public sentiment, but it’s not as though this group of people involved has suddenly changed their minds and every parent is bringing in their unimmunized children,” Schaffner says. “I think there will continue to be people who wish to exercise their ‘freedom’ or options and withhold their children from vaccination, science be darned.”

18th Century Antivaxxers

While it may seem like a relatively recent phenomenon, the antivaccine movement began with the first vaccine, Offit told APIC attendees. In 1796, Edward Jenner developed a smallpox vaccine using the antigenically similar cowpox virus.

“There were antivaccine movements born within a year of that invention,” he said, showing inflammatory editorial cartoons from the time depicting people turning into animals after receiving the smallpox vaccine.

“We look at this picture and we laugh, but some of the objections that are raised about vaccines today are about as biologically plausible as this picture,” Offit said.

For example, Offit said he was asked recently about the rumor that vaccines contain fetal embryonic cells of both males and females, causing some people to become transgender after immunization.

“I answered that question the only way one reasonably could,” he deadpanned. “Yes, that’s exactly how it happens.”

The modern antivaccine movement began in 1982 with the pertussis vaccine, as televised news coverage showed horribly disabled children who had been immunized recently.

“The parents all told the same story,” he said. “My child was fine, then they got this whole-cell pertussis vaccine and look at what happened. This really created the notion in this country for the first time that vaccines might be doing more harm than good.”

The result was congressional hearings, sensational press coverage, and litigation that led to the closure of several vaccine manufacturers. With manufacturers facing the expense of lawsuits, the cost of the pertussis vaccine rose from 19 cents in 1980 to $12 in 1986, he said.

“The number of oral polio vaccine makers declined from three to one, measles vaccine makers from six to one, and pertussis vaccine makers from eight to one,” Offit said. “The one pertussis vaccine maker left was about to leave the business. They were spending more money defending lawsuits than they were making from vaccines. We were about to lose vaccines in the United States in the mid-1980s.”

Passage of the federal National Childhood Vaccine Injury Act in 1986 was able to “stop the bleeding” and stabilize vaccine production. But a national antivaccine movement continued and developed more sophisticated marketing techniques to cast doubt on vaccine safety.

Epidemiological studies over the next decade showed that pertussis vaccine was not associated with increased risk for epilepsy, developmental disorders, or brain damage.

“Genetic studies 25 years later, now that we had the tools at hand, showed that the children [shown on TV] had something called Dravet syndrome, which had nothing to do with vaccines,” Offit said. “But these studies came far too late to stem the fear that the pertussis vaccine was causing permanent harm.”

Measles and the Damage Done

In 1998, The Lancet infamously published a since-retracted “study” that fueled fears that the MMR vaccine may cause autism. The journal’s editors retracted the article in 2010 in 2010 after years of controversy and criticism from the medical community. The journal cited several “incorrect” elements and the lack of ethics committee oversight in concluding, “we fully retract this paper from the published record.”3

But the damage was done and the false link between autism and the MMR vaccine eventually resulted in measles outbreaks, first in the United Kingdom and then later in the United States.

“Many people in the United Kingdom chose not to vaccinate their children,” Offit said. “Thousands of people made that choice. Hundreds of people were hospitalized with measles, and there were four children who died.”

As parents in the United States subsequently refused to vaccinate their children, a series of measles outbreaks began that continues today.

“The only reason that it has come back is because a critical number of parents have chosen not to vaccinate their children,” he said. “I really think this has turned public sentiment against the antivaccine movement. I think the tide has turned.”

The media now is more skeptical of antivaccine claims, and most parents with autistic children do not blame MMR vaccination as the cause, Offit said.

“A study reassuredly found that 85% of parents with children with autism don’t believe that vaccines were the cause,” he said. “You may hear from this very vocal, politically savvy, media-connected group who believe that vaccines cause autism. But that is not true of most parents whose children are on the spectrum.”

Another favorable sign is that recent films and documentaries placing vaccines in a critical light and lionizing the antivaccine movement have not found much of an audience, he said. Hopes were buoyed in the antivaccine movement when Donald Trump was elected president after linking vaccines and autism in one of the presidential debates, Offit said. However, no subsequent action has been taken in that regard, and administration health officials have underscored the safety of the MMR vaccine during the current measles outbreak.

After a widely publicized outbreak of measles at Disneyland, California passed a law in 2015 eliminating personal or philosophical beliefs as an exemption to childhood vaccinations for school attendance. With West Virginia and Mississippi, that resulted in three states with medical exemptions only. Several other states are considering or are in the process of taking similar action to close loopholes to childhood immunizations.

“This is really dramatically different from where we were in the early 1980s,” Offit said.

Showing a slide of a young boy with leukemia speaking at a hearing on the bill in California, Offit said his testimony was essentially the voice of society.

“He knew that he couldn’t be vaccinated,” he said. “He got up the microphone and said, ‘What about me? Don’t I count? I depend on you to protect me.’ There really wasn’t much the antivaccine people could say to that.”

Although many of the claims and fears are false, there are rare risks associated with immunizations, he noted. For example, the oral polio vaccine, which is no longer used in the United States, could cause polio in rare cases, Offit said.

“The oral polio vaccine was really the only live attenuated vaccine that had the capacity to revert to a virulent or wild-type virus and cause polio,” he said. “It happened in roughly one per 2.4 million doses. It was a rare but real phenomenon.”

Similarly, the yellow fever vaccine is a rare cause of yellow fever, and the influenza vaccine has been linked to Guillain-Barré paralytic syndrome at a rate of about one in 1 million immunizations.

“It’s OK to let people know about that, but autism is not an issue,” Offit said. “The antivaccine folks have also embraced this notion that vaccines are causing chronic diseases like chronic fatigue syndrome, pain, multiple sclerosis, and diabetes. That is not true. Their platform is built on sand.”


  1. Centers for Disease Control and Prevention. Measles cases and outbreaks. Available at: Accessed Aug. 9, 2019.
  2. Hviid A, Hansen JV, Frisch M, et al. Measles, mumps, rubella vaccination and autism: A nationwide cohort study. Ann Intern Med 2019;170:513-520.
  3. Editors of The Lancet. Retraction — Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Lancet 2010;375:445.