Florida’s surgeon general said Sunday that he had not weighed the cost – in terms of infections, hospitalizations or deaths – of ending vaccine mandates in his state. But scientists who have done those calculations say those costs may be high.
Asked by CNN’s Jake Tapper whether he had done any data analysis or projections of how many new cases of vaccine-preventable disease there would be if the mandates were lifted for everyone in Florida, including schoolchildren, as he proposed last week, Dr. Joseph Ladapo answered, “Absolutely not.”
“Do I need to analyze whether it’s appropriate for parents to be able to decide what goes into their children’s bodies? I don’t need an analysis on that,” he said.
Scientists have crunched the numbers, however.
Infectious disease forecasters at Stanford University who recently looked at the effects of falling vaccination rates across the country found that in Florida alone, a 15% decline in vaccinations against measles over 25 years would lead to 1 million measles cases.
The state is particularly vulnerable because of its large population and brisk tourism industry, according to lead study author Dr. Mathew Kiang. Disney World in Orlando has often been the site of measles cases imported from other countries, for example.
“Unvaccinated groups in the United States are sort of like tinder, and vaccines are sort of fire protection, and so every imported case is like throwing a match into the fire,” said Kiang, an assistant professor in the Department of Epidemiology and Population Health. “For most of them, nothing is going to happen, but what you don’t want is a situation where one happens and then it comes roaring back like a wildfire.”
For every 1,000 measles cases, there are between 1 and 3 deaths from breathing complications or brain swelling. If there are a million cases, that’s about 1,000 deaths that doctors consider preventable with the use of vaccines.
“I think what our study has illustrated is that the US is really on the tipping point for measles reemergence,” said senior study author Dr. Nathan Lo, an infectious disease specialist at Stanford. “Even small declines like five or ten percent should really put us on that path.”
Another analysis, modeled by researchers at the University of Florida’s Center for Statistics and Quantitative Infectious Diseases last week after Ladapo’s announcement, suggests that even a small drop in measles-mumps-rubella (MMR) vaccine coverage among kindergartners in Florida – from the current rate of about 89% down to 85% – could raise the risk of measles spread and the size of outbreaks in the state.
The likelihood of an infected child spreading the disease would rise from 85.5% to nearly 93%, the analysis found, and the average outbreak in a school of 200 students would rise from 20 to 32 students.
“We wanted to show the potential impact of further decrease in vaccine coverage in the schools and beyond, and we picked the most transmissible infection, measles, as an illustration. Of course, the transmission of other infectious diseases would increase as well,” said Dr. Ira Longini, an author of the analysis and professor of biostatistics at the University of Florida.
Vaccination rates have been falling nationwide as more states allow parents to opt out of school mandates for religious or philosophical reasons and vaccine skepticism rises, fueled by rampant misinformation on social media.
In many areas, vaccination rates have fallen below the 95% threshold in kindergarteners needed to create herd immunity against measles. Because measles is so contagious, it takes high levels of vaccination to keep it from spreading in the population.
Thanks to vaccines, the US eliminated measles as a regularly transmitting disease in 2000, but at current levels of vaccination, it will entrench itself again within 20 years, the Stanford study found. Boosting vaccination, on the other hand, would prevent it from becoming a regularly occurring infection again. The study was published in April in the medical journal JAMA.
But other infections are less contagious than measles, so it would take a bigger drop in vaccination rates for diseases like rubella, polio and diphtheria become a regular risk again.
If childhood vaccinations in the US drop by half, the study predicted 51.2 million cases of measles over 25 years, 9.9 million cases of rubella, 4.3 million cases of polio and 200 cases of diphtheria. That would result in an estimated 51,200 cases of brain damage from measles, 5,400 cases of post-polio paralysis, 10.3 million hospitalizations and an average of 159,200 deaths.
A 50% drop in vaccination rates may sound extreme, Kiang said, “but I will say that I think it is within the realm of possibility.”
The government’s attacks on vaccine infrastructure could mean some pharmaceutical companies leave the country or stop producing vaccines. Insurance companies could stop covering them, and changes to vaccine recommendations could make inoculations more difficult to access.
Kiang also said people might be more afraid to go to their doctors to get a vaccine amid a climate of increased immigration raids and deportations.
“Vaccines have an incredibly high approval rating among Republicans and Democrats, but I think [the decline in vaccination] is about the infrastructure itself,” Kiang said. “It wouldn’t be solely because people decided to stop getting them.”
Do mandates matter?
Sunday on CNN, Ladapo pushed back at the idea that ending vaccine mandates would be consequential for public health.
“We’re not taking vaccines away from anyone,” he told Tapper. “What we said was that if you want them, God bless you, you can have as many as you want, and if you don’t want them, parents should have the ability and the power to decide what goes into their children’s bodies.”
But a report from an independent group of public health experts found “strong evidence” that vaccine mandates significantly increase vaccination rates and decrease morbidity and mortality from vaccine-preventable diseases.
The Community Preventive Services Task Force was established by the US Department of Health and Human Services three decades ago to develop evidence-based guidance on public health interventions. In 2016, the group assessed findings from two dozen studies on the effects of state or local vaccination requirements, most of which were conducted in the US and focused on vaccine requirements to attend school.
They found that vaccine mandates were associated with an 18 percentage point increase in vaccination rates, on average. And the collection of studies showed that vaccine requirements reduced the incidence of measles, mumps, influenza and hepatitis. One study from Japan found that children were more likely to die from influenza and pneumonia after national influenza vaccine mandates were removed.
“Vaccination requirements were not associated with any harms in the identified studies,” the panel wrote in the report.
Ladapo insisted that ending mandates was about informed consent. With them in place, he said, patients can’t truly make an informed decision about their health or the health of their children.
“It’s really about ethics,” he said. “Is it appropriate for a government or any other entity to dictate to you what you should put in your body? No, it’s absolutely not appropriate.”
All 50 states currently allow medical exemptions from these school vaccine mandates, and most allow exemptions due to personal or religious beliefs.
Ladapo also pushed back on the concept that unvaccinated individuals can raise the risk for others in their community – but science shows otherwise.
The MMR vaccine is highly effective – two doses offer 97% protection against infection – but lower vaccination rates in a community raise the risk of exposure.
Dr. Walt Orenstein, associate director of the Emory Vaccine Center, said that 97% immunity “is great, but 3% of those children are still susceptible, though vaccinated.”
“How are they protected? They’re protected if they’re not exposed, and what mandates do is dramatically reduce the chances of that,” he said.
One study found that at least 11% of vaccinated children in measles outbreaks acquired infection through contact with a child who had a vaccine exemption. And the children with exemptions themselves were about 22 times more likely to acquire measles and about 6 times more likely to acquire whooping cough than vaccinated children.
Florida’s exemption rate among kindergartners last school year was 5.1% for at least one vaccine, according to data from the US Centers for Disease Control and Prevention. That’s higher than the 3.6% national average, which hit a record high last year.
But a majority of Florida parents support at least some vaccine requirements for school, according to a survey from KFF and the Washington Post that was conducted in July and August. Eighty-two percent of Florida parents said public schools should require vaccines for measles and polio, with some exceptions.
“There are countries that don’t have vaccine mandates, and the sky isn’t falling over there,” Ladapo said. And he argued, “We do have outbreaks in Florida, just like every other state, and we manage those. So there are no special procedures that need to be made” to prepare for removing mandates.
Many infectious disease experts think otherwise.
“I vigorously disagree,” Orenstein said. “Certainly, for measles, one of the problems is that it is often very difficult to trace transmission because infected people become contagious before they’re very sick.”
Polio is another example of a disease that can spread rapidly, ahead of efforts to contain it. Most polio infections don’t cause symptoms, and fewer than 1 in 100 infections result in paralysis. “If you develop paralytic polio, the likelihood is that you will never know who gave it to you,” Orenstein said.
For diseases like these, the only way to stop devastating outbreaks is widespread vaccination, Orenstein said.
In the 1970s, there was a major measles outbreak in Texarkana, which spans the Texas-Arkansas state line. Arkansas required vaccines for school, while Texas did not. As a result, Arkansas saw relatively few cases while Texas experienced the lion’s share, Orenstein added. The case study was published in 2006 in The Pediatric Infectious Disease Journal.
Canada is another useful comparison. That country doesn’t universally require that children be vaccinated to go to school. Despite having a much smaller population than the US – 40 million people compared with 335 million, respectively – it has had many more measles cases reported this year: nearly 4,800 by September, according to Health Canada, compared with 1,431 in the US, according to the CDC.
Dr. Isaac Bogoch, an infectious disease specialist at Toronto General Hospital Research Institute, disagrees with Ladapo that the measles outbreak in Canada hasn’t been a significant event.
Up to 8% of infected people have been hospitalized, he said, a brutal toll in a developed country. An infected infant died.
“I think most in the general public and in the health care and public health communities would feel that this was a very large outbreak and unacceptable,” Bogoch said. “It’s an unfortunate sign of perhaps shifting attitudes towards public health measures that have really kept children and the population safe for decades.”
Vaccination rates are falling in Canada, just as they have in the US and many other countries. That was partly due to the disruption in routine medical care during the Covid-19 pandemic and partly due to rising distrust in vaccines, Bogoch said.
“The rhetoric and the dismantling of institutions or policies that promote vaccination will have a predictable effect,” he said. “And we’re seeing the results of that right now.”
CNN’s Meg Tirrell contributed to this report.
