New "bivalent" vaccines target Omicron subvariants as well as the original strain that emerged in China Photo: AFP/File
health

How the new bivalent COVID vaccines work

27 Comments
By Marie-Morgane Le Moel

France became the latest country on Tuesday to authorize new COVID-19 vaccines that have been updated to target Omicron subvariants ahead of autumn booster campaign.

Here's what you need to know about these "bivalent" vaccines, which means they also still target the original strain that emerged in the Chinese city of Wuhan in 2019.

Mutating to evade immunity

Two of the first vaccines developed to fight the original strain were made by the U.S.-German team of Pfizer-BioNTech and by U.S. firm Moderna, both using new mRNA technology.

While traditional vaccines use a weakened or inactivated germ to prepare the body for a future attack from the real virus, mRNA deploys snippets of genetic material that carry instructions showing the body's cells how to produce a protein -- in this case, COVID's famous spike protein.

The body's immune system then triggers antibodies to fight off that spike protein, making it ready for when the real coronavirus comes knocking.

However, the COVID virus has mutated throughout the pandemic, growing new spikes to help it evade the immune response built up by the original vaccines.

The Omicron variant, which has milder symptoms but is more infectious, has become dominant across the world this year -- particularly in recent months its subvariants BA.4 and BA.5.

Vaccine makers have been racing to catch up, aiming to provide updated booster shots ahead of an expected new wave of COVID cases in the northern hemisphere's winter.

Pfizer-BioNTech and Moderna first tweaked their original vaccines to include the spike protein seen in the BA.1 subvariant, while also still targeting the original strain.

Then both vaccines were further tweaked to include the spike proteins on the BA.4 and BA.5 subvariants.

The U.S. Food and Drug Administration approved both BA.4/5 vaccines late last month, and officials there hope millions of Americans will receive bivalent boosters throughout September.

The European Union's medicines watchdog EMA approved Moderna and Pfizer-BioNTech's BA.1 vaccines at the start of this month.

The EMA then approved Pfizer-BioNTech's BA.4/5 last week, saying its recommendation was based on clinical data from the older BA.1 version.

Canada meanwhile authorized Moderna's BA.1 vaccine at the start of September.

Clinical trial data remains sparse for the newest BA.4/5 vaccines, which the U.S. approved based on animal studies showing they produced a greater immune response and lowered levels of the virus in the lungs, compared to older shots.

Antoine Flahault, director of the Institute of Global Health at the University of Geneva, said he was "still not convinced" about the superior efficacy of the BA.4/5 vaccines because there had not yet been clinical trials into their effectiveness.

However, the vaccines are "very promising" and have no new safety concerns, Flahault told AFP, adding that there would be much more data in the coming weeks as the U.S. bivalent booster campaign gains steam.

The concept of adapting a new vaccine without carrying out full clinical trials every time is not a new one.

Influenza vaccines are updated annually, and are now quadrivalent, targeting components of two influenza A and two influenza B viruses.

U.S. health officials have said that in the future newly updated COVID boosters could be recommended every year, similar to influenza vaccines -- unless drastically different variants emerge.

On Tuesday France's National Authority for Health gave the green light for three bivalent vaccines -- Moderna and Pfizer-BioNTech's jabs targeting BA.1, as well as Pfizer's against BA.4/5.

The French health authority recommended that those at risk of severe disease or caregivers get any one of the three vaccines as soon as they become available as part of an autumn booster campaign.

France has already ordered several million doses of bivalent vaccines from Pfizer-BioNTech and Moderna, the health ministry told AFP.

There are already signs of a COVID resurgence in France, where the number of cases jumped by more than 65 percent last week after two months of decline.

Other vaccine makers are working on bivalent jabs, including one from France's Sanofi and Britain's GSK that targets the earlier Delta and Beta strains.

The EMA is reviewing that vaccine as well as another from the Spanish pharma firm HIPRA targeting the Alpha and Beta strains.

© 2022 AFP

©2022 GPlusMedia Inc.

27 Comments
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director of the Institute of Global Health at the University of Geneva, said he was "still not convinced" about the superior efficacy of the BA.4/5 vaccines because there had not yet been clinical trials into their effectiveness.

A global expert confirming that no clinical trials have been done.

-6 ( +10 / -16 )

A global expert confirming that no clinical trials have been done.

Clinical trials have been done with omicron variant booster that demonstrate an increase of efficacy, so this argument is not correct. Not being convinced is more about the limited number of patients participating on those trials, but that is nothing new nor something only used for covid vaccines. The animal trials just support that the same effect being found for others versions of the omicron booster also apply for another of those versions, which is a valid scientific argument to make in abscense of data that would indicate this surrogate of comparison is invalid.

That is, no safety concerns over and above the potentially deadly problems such as myocarditis, blood clots and the like that have already been identified, and suffered by young and otherwise healthy people who'd still be alive today if they hadn't needlessly taken the earlier shots.

This is still disinformation being repeated in spite of being repeatedly disproved, no vaccine have any of the risks you list in the much higher degree that covid has, which means that no, without vaccines more people would be dead thanks to "myocarditis, blood clots and the like" that are hugely more common for infected people than for any vaccine, including young people.

Repeating things that have been demonstrated as false means you have no actual true information to criticize the vaccines, so you have to use things repeatedly disproven.

-1 ( +8 / -9 )

@Bronco: But you fail to quote the rest of his statement:

However, the vaccines are "very promising" and have no new safety concerns, Flahault told AFP, adding that there would be much more data in the coming weeks as the U.S. bivalent booster campaign gains steam.

Also:

The concept of adapting a new vaccine without carrying out full clinical trials every time is not a new one.

Once again - just choosing out of context selective sentences comrade.

1 ( +11 / -10 )

You can parrot the lies of the approved narrative all you like and get protected by the moderators,

Endlessly repeating false information that you make no effort to defend when proved false is not "protecting" lies, on the opposite it is just eliminating useless false information from the discussion.

When you are unable to prove your arguments are real but you still choose to repeat them you are contributing nothing to the discussion, just using things you know to be false.

1 ( +9 / -8 )

the U.S. approved based on animal studies 

Sounds ominous. No scientific studies published in peer reviewed articles for this shot.

BroncoToday  07:24 am JST

A global expert confirming that no clinical trials have been done.

Exactly.

-5 ( +8 / -13 )

Sounds ominous. No scientific studies published in peer reviewed articles for this shot.

What is ominous about it? that is what happens with every year Influenza shots, no studies published because there is nothing new about a new formulation of an extensively tested shot is still safe and effective.

Exactly

No, not exactly, as already quoted from the article

However, the vaccines are "very promising" and have no new safety concerns, Flahault told AFP, adding that there would be much more data in the coming weeks as the U.S. bivalent booster campaign gains steam.

The concept of adapting a new vaccine without carrying out full clinical trials every time is not a new one.

Cherry picking half of a commentary is useless when the whole thing is still there and clearly supports the opposite point of view.

2 ( +10 / -8 )

No scientific studies published in peer reviewed articles for this shot.

So, just like every Chinese and Russian covid vaccine?

5 ( +10 / -5 )

A global expert confirming that no clinical trials have been done.

Clinical trials have been done with omicron variant booster that demonstrate an increase of efficacy, so this argument is not correct.

The bivalent based on BA.1 was tested in humans, and the one based BA.4/BA.5 was only tested in mice.

But in both cases, they only tested for production of serum antibodies, not for effectiveness at preventing infection or symptoms.

-3 ( +3 / -6 )

A global expert confirming that no clinical trials have been done.

5 billion vaccines administered worldwide, no mass deaths, no mass life threatening side effects,

meanwhile deaths from covid now at 6.5 million and rising

5 ( +10 / -5 )

The bivalent based on BA.1 was tested in humans, and the one based BA.4/BA.5 was only tested in mice.

That still means the omicron vaccine has clinical data to prove its safety and pretending only data from on single version of the booster is used to get approval is false.

But in both cases, they only tested for production of serum antibodies, not for effectiveness at preventing infection or symptoms.

That is false, the testing is about the neutralization ability of the antibodies, which is a well characterized surrogate for protection according to the scientific and medical authorities that deal with the pandemic. That means that unless you have data to contradict this characterization the titers are a valid way to evaluate protection caused by the vaccine.

Do you have that data?

2 ( +7 / -5 )

A global expert confirming that no clinical trials have been done.

5 billion vaccines administered worldwide, no mass deaths, no mass life threatening side effects, meanwhile deaths from covid now at 6.5 million and rising

He was referring to the bivalent, you're referring to the original monovalent, which BTW has resulted in mass deaths countless serious adverse effects (see VAERS and similar systems in other countries).

But in both cases, they only tested for production of serum antibodies, not for effectiveness at preventing infection or symptoms.

That is false, the testing is about the neutralization ability of the antibodies...

Analyzed in vitro, no data to show effectiveness at preventing infection or symptoms. You claimed clinical trials demonstrated an increase of efficacy; I am simply pointing out that that was not done.

-5 ( +3 / -8 )

He was referring to the bivalent, you're referring to the original monovalent, which BTW has resulted in mass deaths countless serious adverse effects (see VAERS and similar systems in other countries).

There is no safety concerns with the new boosters as proved by the clinical data from literally millions of people infected with omicron strains that prove that the sequence of the spike protein (the only new thing on the formulation) brings no extra risk above what has been observed with the original sequence.

And no, The data on VAERS and other data bases do not say there are mass deaths and countless serious adverse effects according to the professionals that evaluate and keep those databases for a living. That is only disinformation being pushed by antivaxxer groups that want to hide that rates of problems are the same in vaccinated and unvaccinated people, so they can pretend completely normal things observed on people just because they are alive all are because of the vaccines, that is obviously not the case because that would require an excess over unvaccinated people.

Analyzed in vitro, no data to show effectiveness at preventing infection or symptoms.

No, the clinical data used for the approval includes clinical data of this, again, since neutralization titers are a well characterized surrogate of protection that means those results CAN be used to demonstrate protection, that is the whole point of making something a surrogate.

So again, if you say that is not equivalent to protection that means you can contradict the experts that say it is, do you have the necessary data to disprove it? or is this just supposed to be based on some appeal to your authority on the field?

1 ( +6 / -5 )

Another great tool to reduce your chances of getting a severe case!

1 ( +7 / -6 )

since neutralization titers are a well characterized surrogate of protection that means those results CAN be used to demonstrate protection

Paul Offit, a vaccine researcher at the Children’s Hospital of Philadelphia (member of FDA’s vaccine committee), begs to differ. He described that in the early studies (Dec 2020) Moderna gave 2X more neutralizing antibodies than Pfizer, but that did not translate into comparable greater effectiveness; i.e. more neutralizing antibodies does not equal greater protection.

So again, the experiments on the BA.1 bivalent vaccine showed an increase in neutralizing antibodies, and it is misleading to say that they "demonstrated an increase of efficacy". They is no evidence demonstrating greater effectiveness. And we have even less data with the BA.4/BA.5 bivalent vaccine, which was only studied in mice.

-2 ( +4 / -6 )

Paul Offit, a vaccine researcher at the Children’s Hospital of Philadelphia (member of FDA’s vaccine committee), begs to differ.

Beg to differ? has he said that neutralization titers are not a valid surrogate of protection? do you have a link for that? because your comment is completely different from that. Also if you are using Paul Offit as a valid reference that means you agree with what he has to say about the vaccines right? because he has made it completely clear he thinks being vaccinated and boosted is a huge reduction of risk much preferable to risking the infection, which is the opposite of what you wrote before, In fact his opposition to updating the boosters is because he consider the current formulation completely adequate to provide immunity against even omicron in the first place.

So, if you are going to consider him a reliable source it means you accept you have been wrong by contradicting him, and if you think he is wrong that means you do not consider him a reliable source, you can't have both things.

So again, the experiments on the BA.1 bivalent vaccine showed an increase in neutralizing antibodies, and it is misleading to say that they "demonstrated an increase of efficacy"

No, it is not misleading unless you can provide data that disproves the validity of them being surrogates of protection.

The question is the same do you have that data? Not an appeal to authority that completely contradicts what you have said, but data that disproves neutralization activity as a surrogate for protection.

-1 ( +4 / -5 )

So, is a bivalent vaccine available in Japan? If not, when does the Ministry of Health expect one to be available? What makes this article relevant to Japan?

In other irrelevancy, I got a Moderna bivalent booster last Saturday, Septmber 17, along with a flu booster for this fall. I felt out-or-sorts with aches and a fever on Sunday, and was hurting until about 24 hours aftr the booster.

Now, will my having had four Corona shots make any difference to Japanese immigration officials when I show up at Haneda in the next few months for independent tourism and wandering around? Will I be able to enter all my Covid booster info on MySOS?

0 ( +1 / -1 )

I am done, no more for me, 3 is my limit and that is so no more quarantining.

2 ( +4 / -2 )

So, is a bivalent vaccine available in Japan? If not, when does the Ministry of Health expect one to be available? What makes this article relevant to Japan?

The bivalent booster became available in Japan for people over 60yo as a fourth dose since yesterday, and it will be expanded for everybody above 12yo that have had at least two doses from October.

Unfortunately the situation with tourists has been completely irregular so it is difficult to predict what is going to happen, things right now look better for people coming to the country but nothing can be guaranteed.

-1 ( +3 / -4 )

Does it work?

I thought the definition of a vaccine was to stop contagion….oh that’s right… they moved the goal posts when Covid came along…now it is “reduces the infection time” by a whole 5%….

-1 ( +4 / -5 )

I thought the definition of a vaccine was to stop contagion

Well that is a false definition antivaxxer groups pulled out of thin air just to pretend the covid vaccines are different from the previous ones, that are not meant to stop contagion either.

There is a reason there are no poliovirus vaccines, rabies virus vaccines or influenza virus vaccines, that is because the vaccines are meant to reduce the risk coming from the infection, not the infection itself.

now it is “reduces the infection time” by a whole 5%….

No, now and always have been "reduce the severity and lethality of the disease they protect against", which is something the covid vaccines do remarkably well.

-2 ( +2 / -4 )

The finest minds, PhD.-level experts in virology, communicable disease, immunology and public health really never looked at the knocks our resident "experts" have about this vaccine (but who will very likely take their flu shot - also "untested")?

Seriously? You're the only ones who could think of these issues?

I find that " highly implausible."

So go with the non peer-reviewed "study" your cousin found on Facebook. I'm going with ACTUAL experts.

-2 ( +3 / -5 )

Nevee had flu until I got the shot 20 years ago. So never again, and never had it before or since. Concerning Covid so pissed off I got the two shots (second almost killed me, and only reason I got it was due to severe peer pressure). Never had Covid before that, and not since, that I know of. Know heaps of people who have had Covid, and 2,3 and planning for fourth shot.

And what is this new shot? Effective against severe symtpms against Omicron (which is no worse than a light cold) which they estimate has got to 90% of people anyway,, vaxed or not.

No more for me. But if you want to get vaxed, be my guest!

-1 ( +3 / -4 )

Compared with the risk of infection of COVID-19 and the vaccine's side effects, it's a tricky problem which better chooses have a vaccine or not. However, I think the former is more dangerous to us. Some studies showed brain fog, long periods of fatigue, and so on; long-term results after COVID-19. It's so-called long COVID-19. Getting a vaccine means prevents from the aftereffects of a new contagion.

-2 ( +2 / -4 )

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