Thread by @jeffgilchrist

Some are describing the #Novavax #vaccine having the ability to target the parts of the #virus that stay the same. This is a little misleading since Novavax + #adjuvant and your immune system have no idea what parts of the #spike are going to change in new #variants. 🧵1/

Instead, the adjuvant in Novavax (Matrix-M) helps your immune system target a larger set of unique parts on the spike so new variants may have less of an impact with Novavax vaccines depending on where the mutations happen ( ). 2/

https://twitter.com/jeffgilchrist/status/1700854098755563660

While the original Novavax elicited antibodies that target parts of the spike that happened to be conserved in BA.1 and BA.5 ( ), those parts got changed with the latest XBB variants requiring an updated formula. 3/ medrxiv.org/content/10.110…

Thankfully today the updated Novavax booster was approved by the FDA in the USA for individuals aged 12 and older, no matter what their previous vaccination history is ( ). 4/

https://twitter.com/Novavax/status/1709278869868499446

People may be confused as to why they can't just keep getting the original Novavax if they think it targets parts that don't change which are and have been changing and now require an updated formula. 5/

Maybe a better analogy would be security guards are told not to allow an individual into their building. The mRNA antibody guards are given a set of unique tattoos to look out for to identify this individual. 6/

The Novavax adjuvant antibody guards are given a somewhat different and larger set of unique tattoos for the same person. 7/

Over time the individual tries using laser treatment to change their tattoos to foil the guards and happens to change most or all of the tattoos (BA.1, BA.5) that the mRNA antibody guards are aware of so they can sneak into the building. 8/

The Novavax guards can still identify the person from some of the different tattoos they know about that haven't changed, but maybe not as easily as before. 9/

Eventually if the individual changes enough of their tattoos (XBB) then none of the guards can identify them. 10/

This might take longer for the guards who are aware of a larger number of tattoos unless the individual gets tipped-off and changes all the tattoos the guards are aware of quickly. 11/

For people who get multiple doses of vaccines, the adjuvanted ones might be like allowing the guards to spend more time memorizing the unique tattoos for easier recall and potentially discovering some new tattoos to remember as well. 12/

However, despite their best efforts, the security guards of course cannot read the mind of the individual, and therefore cannot know in advance which tattoos or which parts of the tattoos the individual might plan to change when they are away from the building. 13/

In this way, there is an inherent limitation on how much protection the security guards (and Novavax vaccine) can realistically add against future changes.

What do people think of this analogy? More confusing? Easier to understand? 14/

Thank you to @paulseaman31 for sending me the adjuvant paper ( … ) and for bouncing ideas back and forth on this analogy. 15/tandfonline.com/doi/full/10.10…