Since Omicron was announced as a concern option in late November, it quickly spread around the world and became the predominant COVID option in many countries, including Australia.
This is not the last and probably not the last of the growing options.
However, each of the hundreds of millions of mRNA vaccines approved worldwide is based on an original recipe based on the COVID virus, which first appeared in Wuhan.
One of the most promising aspects of the new mRNA COVID vaccines is their ability to quickly adjust for maximum protection against new variants.
So where is my Omicron amplifier?
Remind me again: How do mRNA vaccines work?
mRNA-based vaccines contain a plan in the form of genetic material – called messenger RNA – that is “read” by our cells when injected into a muscle.
Using that RNA message as a guide, our cells make copies of the spike protein that the SARS-CoV-2 virus uses to infect us.
The newly formed head proteins are pushed outside the flag-like cells, alerting the immune system.
In response, a type of leukocyte called B cells absorbs antibodies – Y-shaped molecules that make up the roof’s immune “memory.”
However, because the SARS-CoV-2 virus changed its genetic code and slightly altered the protein, it was able to fly under the radar of our immune system.
Juniper Fox, an RNA biologist at the University of Western Australia, says the process of adapting mRNA vaccines to new variants is “very simple.”
“The beauty of RNA [vaccine] The platform can easily modify the DNA pattern used to make RNA.
“It’s the bread and butter of biochemists and molecular biologists, so to speak [vaccine] companies. “
Colin Pouton, a pharmaceutical biologist at Monash University, says large companies like Pfizer and Moderna can make a special vaccine for Omicron for testing within a week.
So, first, they test whether the Omicron vaccine does the same in mice.
– But if you experiment with animals [with an Omicron-specific booster shot]and seek protection from Omicron, the Omicron version of their vaccine does not actually produce any better results than the original Wuhan vaccine, ”said Professor Pouton.
What is happening then?
The little key to immunity
Giving a person (or mouse) several vaccines with slightly different compositions can cause a phenomenon called “immunological imprinting.”
“When you give a vaccine, you activate the immune response to produce antibodies … and then boost it by giving a second dose or a third dose,” says Professor Pouton.
However, if you are then vaccinated against a slightly different variant, there may be fewer antibodies working on that new viral variant.
This is because when confronted with a similar vaccine, your immune system prefers to process the B-cells that produce the current antibodies, rather than developing new antibodies.
(This can also happen with the seasonal flu vaccine, and is partly because it is effective. But it still needs to be taken.)
And not all antibodies are created equal.
When our immune system receives the spike protein, it recognizes different parts of the spike and begins to develop antibodies that stick together.
Antibodies that help stop the virus from infecting cells are called neutralizing antibodies.
We want these, and they work by blocking the very tip of the virus’s so-called “receptor-binding domain.”
This is a beetle that attaches to the ACE2 receptors in our cells and allows the virus to enter.
Another way to think about this is to imagine that the speaker protein is a hand, and the last part is the hand that holds the ACE2 door handle and unscrew it.
If you get a really large, oversized clothing peg – it’s a neutralizing antibody – and you squeeze it into the palm of your hand or between your fingers, you have a physical barrier between the hand and the door handle and it won’t open the door and infect the cell.
Pegs that hang from the elbow or near the shoulder cannot stop the hand from working. These pegs are our neutralizing antibodies.
Non-neutralized antibodies make up the bulk of the antibodies produced by the COVID vaccine, says Dale Godfrey, an immunologist at the Peter Doherty Institute for Infection and Immunity.
“When fully immunized in humans, only 10 to 20 percent of antibodies bind to the receptor-binding domain.”
So how do we get around this?
Researchers are looking for ways to neutralize antibodies by avoiding immunological imprinting.
One way to do this is to create “lean” versions of special vaccines.
Professors Pouton and Godfrey are testing two such vaccines.
One contains instructions for the mRNA vaccine to create a receptor-binding domain for our cells, not the rest of the spike, and the other contains laboratory-made receptor-binding domain proteins.
“We’re trying to say [to the immune system]“Here’s a new target you’ve never seen before,” says Professor Pouton.
The vaccines in the test are based on the Beta option, as this was a concern at the start of the project.
The beta version shares some of the Omicron mutations, says Professor Godfrey.
“We wonder if this vaccine will provide the best protection against Omicron, but we don’t know yet.”
Pfizer and Moderna are continuing clinical trials to find out what vaccines specifically for their Omicron are in humans.
Modernna is also testing a “bivalent” version that combines the original vaccine as well as the new Omicron-specific mRNA.
You may not have to wait long to see how well they work.
A Pfizer spokesman said they would share next-generation vaccine data “in the coming weeks”.
A spokesman for Moderna said the company expected to receive the first information on the bivalent vaccine this month “to inform the selection of a candidate for the northern hemisphere. [autumn] 2022 Booster “.
According to Professor Pouton, Moderna is also testing the first phase of a receiver-related domain Omicron amplifier, but these are very early days.
Finally, he adds, COVID vaccines can become regular seasonal vaccines like the flu vaccine every year and do not need to be tested every time.
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