(Bloomberg) -- Of the many unorthodox positions taken by Robert F. Kennedy Jr., US President-elect Donald Trump’s nominee to head the Department of Health and Human Services, none worries US public-health experts more than his embrace of the anti-vaccine movement. If he assumes the position, he could influence the leadership of agencies in charge of approving, recommending and distributing vaccines in the US. Plus, Kennedy, who emerged as one of the leading voices in the anti-vaccine movement during the Covid-19 pandemic, would have a powerful pulpit from which to further spread misleading messages about immunization.
The global anti-vaccine movement, which first took hold in the US, already has undermined advances against preventable infectious diseases such as measles and whooping cough. There are risks with all pharmaceuticals, especially new ones — vaccines included. But the belief that well-established immunizations against childhood diseases are more dangerous than beneficial is based on fraud.
What are the roots of vaccine hesitancy?
While opposition to immunizations has been around for as long as the shots, the most recent anti-vaccine movement took off after the medical journal The Lancet published what turned out to be a fraudulent study in 1998 linking the measles, mumps and rubella vaccine to autism, a developmental disorder associated with difficulties in speech or social interactions. The Lancet retracted the study in 2010 and the UK’s General Medical Council stripped its author, Andrew Wakefield, of his medical license for “dishonest” and “irresponsible” work. By then many parents had latched on to the idea that vaccines were to blame for a rise in autism diagnoses. A rash of misinformation and conspiracy theories about Covid shots contributed to vaccine skepticism.
What does the evidence say?
Researchers have concluded that much if not all of the increase in autism prevalence is a result of greater awareness of the disorder and changes in how it’s diagnosed. While a true increase hasn’t been ruled out, repeated studies have debunked any connection to vaccines. The myth of a link expanded in 2005 with claims that the vaccine preservative thimerosal causes autism. Numerous studies have shown that vaccines containing thimerosal are safe.
What impact has the anti-vaccination movement had?
The number of children going unprotected from a variety of contagious illnesses has grown amid grassroots campaigns to convince parents incorrectly that immunizations often trigger side effects including autism.
Fears that infants’ immune systems may be overwhelmed by multiple shots given at once has led some parents to space them out, though studies show they are safe when given simultaneously. The result is delayed protection and in some cases vulnerability when doses are missed entirely.
Communities where anti-vaccine sentiment spreads can lose herd immunity, which occurs when so many people are protected a pathogen can’t take hold and dies out. That protection is essential for those who can’t get vaccinated, such as very young infants and people with certain medical conditions. Herd immunity can even benefit those who got vaccinated, since no immunization is perfectly effective.
What’s been the effect on public health?
Vaccine-preventable diseases have made a comeback in the US and Europe, while efforts to slow them in poorer countries have stalled. Although vaccination eliminated measles from the US in 2000, since then international travelers have brought the virus back again and again, sparking outbreaks among the unprotected. Measles is on the rise globally, claiming an estimated 107,500 lives in 2023, most of them children younger than five. Whooping cough, which can be lethal for babies, has also rebounded. Apart from a pandemic lull, it’s remained at elevated levels in the UK since 2012, when it killed 10 people.
What are the risks of new vaccines?
Before regulatory authorities license a new vaccine, it must be tested both for safety and efficacy in thousands of human volunteers. Still, there have been cases where safety issues have arisen after licensure. European regulators in 2011 recommended restricting the use of a new swine-flu vaccine from the company now called GSK Plc after it was linked to rare cases of narcolepsy. Some vaccines have been shown to do the opposite of what they’re designed to do by inducing unwanted immune responses. In the 1960s, an experimental vaccine for RSV, a common respiratory virus, not only failed to protect children, but made them more susceptible. Two toddlers died. In recent years, Sanofi’s dengue vaccine was found to exacerbate symptoms in some who received it.
Covid vaccines, which were first rolled out in late 2020, saved millions of lives and prevented many more cases of severe illness. After millions of people were immunized, complications — sometimes deadly — emerged, though these have proved rare, as confirmed by the largest global vaccine safety study to date, published in the journal Vaccine. The adverse reactions include blood clots; anaphylaxis, which is a severe yet treatable allergic reaction; and two types of heart inflammation: myocarditis, involving the heart muscle, and pericarditis, which affects a membrane around the heart. Still, the benefits of getting a Covid vaccine have been shown to far outweigh the risks.
How do authorities watch out for adverse reactions to vaccines?
Most advanced countries have established systems for reporting adverse side effects of vaccines. In the US, anyone can submit a report to the Vaccine Adverse Event Reporting System, which serves as an early warning system to identify side effects. The UK has a similar program, called the Yellow Card Scheme.
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