RFK Jr’s New Vaccine Advisors Just Recommended Fall Flu Vaccines – But There’s A Catch

After controversially firing the old team, US health secretary Robert F Kennedy Jr’s new picks for the USA’s top panel of vaccine advisors are now getting down to business, and they’ve been holding some pretty key votes. One of the most notable surrounds flu vaccines, which they voted to recommend – that is, as long as they don’t contain an ingredient called thimerosal. But what exactly is that, and why has the panel focused on it?

What is thimerosal?

One of the most important parts of the vaccination process is to stop vaccines from becoming contaminated with microbial nasties during their use. This can happen when a single vial of vaccine contains more than one dose; a syringe going into the vial multiple times presents multiple opportunities for germs to be introduced. 

That’s where thimerosal comes in – it’s a preservative that can prevent the growth of things like bacteria and fungi, helping to reduce the chances of infection. It’s been used in this way since the 1930s, though according to the Food and Drug Administration (FDA), its use has “significantly declined” since then thanks to the reformulation and development of vaccines in single-dose vials.

Despite the decline in its use, thimerosal has also become the target of misinformation. This first properly kicked off in the 1970s, a time when the public was becoming increasingly aware of the dangers of organic mercury poisoning.

People were concerned because thimerosal contains a form of mercury – but not all mercury is the same. The type of mercury that can be toxic at high levels is methylmercury – thimerosal contains ethylmercury, which is cleared from the body much more quickly and is less likely to cause us harm.

Things kicked off again in 1999, when the FDA reviewed the use of thimerosal in childhood vaccines. It found no evidence of harm, but recommended removing the compound from routine infant vaccines as a precautionary measure. In 2001, it removed or reduced thimerosal in all vaccines – except that for flu – given to children under the age of 6.

Claims began to circulate that the reason for this was because thimerosal was behind the rise in autism diagnoses at the time. That’s not necessarily surprising – the atmosphere at the time was ripe for the spread of vaccine misinformation, with Andrew Wakefield having earlier made the claim that the measles, mumps, and rubella (MMR) vaccine could be causing autism.

In both cases, the claims made are simply not true. A study from the Centers for Disease Control and Prevention (CDC) published in 2010 found no evidence that exposure of fetuses and infants to thimerosal-containing vaccines increased the risk of autism spectrum disorder.

What did the committee say about it?

Despite the misinformation surrounding thimerosal having been thoroughly debunked, it’s still been circulated – including by RFK Jr, who even co-authored a book peddling false claims about the preservative.

It’s perhaps not all that surprising then that thimerosal, which is still found in some flu vaccines, made its way onto the agenda of the latest meeting of the Advisory Committee on Immunization Practices (ACIP), who gathered at the CDC headquarters in Atlanta, Georgia, this week.

On Thursday (June 26), the panel was given a presentation by Lyn Redwood – the President Emerita of Children’s Health Defense, an anti-vaccine group founded by Kennedy – who argued that thimerosal should be removed from flu vaccines. Redwood didn’t mention autism in her case, but she did claim that thimerosal was a neurotoxin and said: “Removing a known neurotoxin from being injected into our most vulnerable population is a good place to start with making America healthy again.”

Typically, they’d have also been presented with a scientific analysis from CDC experts on the matter – but that didn’t happen. The panelists reportedly were given copies of a CDC document that found no conclusive evidence of an association between thimerosal and autism or other neurodevelopmental disorders. The document had also been posted to ACIP’s website earlier in the week, but was later removed.

After the day’s presentations and a public comment period concluded, the panel got to voting. With one abstention, it chose to stick with the usual recommendation that most people aged 6 months or older get a flu vaccine. When it came to thimerosal, however, it voted 5-1 (with one abstention) that only thimerosal-free, single-dose flu vaccines should be given.

The one vote against the move came from Dr Cody Meissner, a professor of pediatrics at Dartmouth Geisel School of Medicine who has previously served on ACIP and the FDA’s Vaccine and Related Biologic Products Advisory Committee.

“The ACIP makes recommendations based on scientific evidence as much as possible,” said Meissner in response to Redwood’s presentation. “And there is no scientific evidence that thimerosal has caused a problem.”

“Of all the issues that ACIP needs to focus on, this is not a big issue,” he continued, later in the meeting adding, “The risk from influenza is so much greater than the non-existent, as far as we know, risk from thimerosal.”

The result of the vote doesn’t guarantee that the panel’s recommendation will end up forming the CDC’s final recommendations for flu vaccines. That decision is made by the CDC director – who is yet to be confirmed – and also needs to be signed off by the health secretary. However, the CDC usually follows ACIP’s recommendations closely.

Whether or not that will also be the case this time around, we’ll simply have to wait and see.