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Kennedy has a long history of opposing childhood vaccinations and even worked as a lawyer to try to stop kids from getting vaccinated. Now, with the power of the state, he’s directing the CDC to put out false messages about childhood vaccines.

This week he directed the CDC to change their website to question decades of scientific research than have consistently shown no link between autism and child vaccines – saying that the long-time statement that “vaccines do not cause autism” is not evidence-based. This, despite overwhelming evidence showing no link between vaccines and autism.

Autism and Vaccines | Vaccine Safety | CDC

This change is bad and feeds the anti-vax fire with more false information. But that’s not my primary concern. I’m more worried that he will use his authority to make policy changes that will undermine childhood vaccination.

There are 2 ways he could do it.

The first is to get the Advisory Committee on Immunization Practices (now stacked with anti-vaccine people) to remove some vaccines from the recommended vaccine schedule. That would cause the Vaccines for Children program (which provides free vaccines for more than half of American children) to no longer cover those vaccines – making them cash pay for low-income families. Private insurers would then be able to stop covering them, again making them cash pay.

RFK Jr.’s CDC spreads false facts about vaccines, autism, critics say

Kennedy could also go deeper into using false information to claim that there’s a link between vaccines and autism – making autism compensable under the vaccine injury compensation fund, bankrupting the fund.

An insolvent fund would then provide a powerful incentive for vaccine manufacturers to stop making all childhood vaccines (most of which have a very low profit margin). This would make it much harder to maintain production of childhood vaccines and could harm public health on a large scale.

We all need to cross our fingers that Kennedy doesn’t end up ordering a wholesale removal vaccines from the schedule and/or intentionally bankrupting the VICF to get rid of vaccines altogether.

AZPHA continues to urge parents to follow guidance from trusted health professionals like pediatricians, not Mr. Kennedy.

Note: The Advisory Committee for Immunization Practices is meeting on December 4 and 5 – and a large portion of the 2-day meeting is focused on the child vaccine schedule.

Day 2 has ‘votes’ about the child vaccine schedule without disclosing what those votes will be about. My continuing fear is that Kennedy will use his authority to cut shots from the schedule in order to end vaccination through the back door.

Every spring scientists pick which flu viruses to include in the Northern Hemisphere’s fall influenza vaccine. Today we’ll cover the latest influenza surveillance and the content of the 2025-2026 influenza vaccines in the US.

How is the content of the fall influenza vaccine decided? It’s a process that focuses on using the best evidence – but it has challenges because of the wildcards the Southern hemisphere can play during their winter (our summer).

Each spring CDC experts look at flu viruses from all around the world and decide which strains are most likely to circulate during our (Northern hemisphere) influenza season. They check:

• which flu strains are spreading most,
• how the viruses’ surface proteins (especially something called hemagglutinin, or HA) have changed,
• whether existing immunity (from prior infection or vaccination) might not work as well.

Once the strain is selected (usually in March) vaccine makers start growing those picked strains (often in eggs). Because growing and distributing takes time, the vaccine formula has to be selected in the spring.

What Happened in the Southern Hemisphere

The wildcard is in the Southern hemisphere. Flu viruses keep evolving in places like Argentina, Brazil and Australia during our summer – even as US vaccine manufacturers are already making the fall season vaccine. That means a new strain can pop up down under during our summer – but it’s found too late to change what’s in our fall vaccine.

Because the vaccine choice has to be made before all possible changes occur, this means there’s always a bit of “leap of faith” involved.

What’s in the 2025‑26 Vaccine for the Northern Hemisphere

Here are the viruses the CDC recommended for this season (back in March):

• An A/Victoria/4897/2022 (H1N1)pdm09‑like virus
• An A/Darwin/9/2021 (H3N2)‑like virus
• A B/Austria/1359417/2021‑like (B/Victoria lineage) virus

These were picked because they represented what scientists believed would be the most likely flu types to spread.

The New H3N2 Strain: What’s Going On?

As sometimes is the case – the virus evolved in the Southern Hemisphere over our summer (their winter). The new strain isn’t a huge change from what was predicted – but it is a bit different. The new strain is an H3N2 “subclade K” virus – and it’s recently popped up in Canada, the UK, Japan and Europe.

• Subclade K has several new mutations compared to the H3N2 strain that was chosen for the vaccine.
• Early data suggest this variant is already dominant in some regions (for example, the UK found high proportions of H3N2 being subclade K).
• Because it appeared after the vaccine strain was picked—at the tail end of the Southern Hemisphere season—it may mean this year’s vaccine isn’t perfectly matched with what’s likely to circulate in AZ this winter.

What It Means for Vaccine Effectiveness

So, what do these changes mean for how well the vaccine will work? Here’s the assessment:

• Because subclade K has drifted (i.e., mutated) away from the strain used in the vaccine, there’s a reduced match. That means the vaccine might be less effective in preventing mild or moderate illness compared to a perfectly matched season.
• But… the influenza vaccines in pharmacies and doctors’ offices still offer important protection, especially against severe illness and hospitalization.
• For example, early data from the UK show around 70‑75% effectiveness in children and 30‑40% in adults, even with this new K strain dominating circulation.

Bottom Line

• The vaccine for 2025‑26 was chosen carefully, based on the best information that was available in March.
• A new H3N2 variant (subclade K) showed up after the CDC’s recommendation for this year’s vaccine. It has more mutations than expected, so it might reduce vaccine effectiveness somewhat, but we don’t know that for sure yet.
• If this year’s vaccine ends up being less effective than usual it doesn’t appear to be the fault of CDC or Kennedy this time – it’s because the new strain evolved after the vaccine decision was made (and had to be made).
• Even if there’s some ‘immune escape’ because of the new subclade K virus, early data from the UK suggest it’s likely that the vaccine will still provide strong protection especially for children and seniors and for reducing hospitalizations.

See all the recommendations: Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2025–26 Influenza Season | MMWR