Thursday, December 09, 2021

Omicron may be able to evade vaccines. Here's what Pfizer, Moderna and AstraZeneca plan to do about that

The United States led the global race to develop a viable vaccine against COVID-19.

But a year after the first shots received emergency approval from federal regulators, new variants of the virus are changing the game.

Omicron, the wildcard variant already detected in multiple US states and more than 30 countries, including Australia, is the latest to emerge.

With its dastardly combination of mutations, scientists fear it may spread quickly and sidestep vaccines.

A small study out of South Africa suggests the Pfizer vaccine provides only partial protection from Omicron, but boosters might make up the difference.

Governments and companies worldwide are already moving to stop the variant wreaking havoc, with some floating the possibility of variant-specific booster shots.

Here's what's happening so far, and what it could mean for you.

One of the biggest questions facing scientists as they scramble to learn more about the Omicron variant is how existing COVID-19 vaccines will perform against it.

"There are three main characteristics that we worry about with viruses like Omicron," said Dr Celine Gounder, an epidemiologist from the NYU Grossman School of Medicine.

"First of all, is it more infectious or contagious?

"Number two, is it more virulent or less virulent? In other words, does it cause less-severe disease in individuals who are infected?

"And, number three, is it immune-evading? And this is one characteristic of Omicron that is concerning."

The new variant has around 50 mutations — more than double its predecessor, Delta — including many on its spike, the viral protein that vaccines or illness train the body's immune system to fight with antibodies.

Even so, Dr Gounder is optimistic current vaccines will continue to provide some level of protection, especially with the addition of booster shots.

"We suspect there may be some reduction in vaccine effectiveness but that people will still remain well protected against severe disease, hospitalisation and death, even with an Omicron infection," she said.

While scientists assess the threat of the new variant, vaccine manufacturers are looking at whether their products may need to be modified.

What are vaccine manufacturers doing?

The makers of US-approved vaccines Pfizer-BioNTech, Moderna and Johnson & Johnson, as well as AstraZeneca — which is widely used in Europe and Australia — have all begun to study Omicron.

"[We] believe that fully vaccinated individuals will still have a high level of protection against severe disease caused by Omicron," said a spokesperson for BioNTech, which developed its shot with Pfizer.

"We anticipate that booster vaccination will further increase protection against severe disease and potentially provide protection against disease of any severity."

In the case of an "escape variant" — a dominant strain of the virus that evades the immunity given by vaccines or previous infections — BioNTech and Pfizer say they can adapt their mRNA vaccine within six weeks and start shipping doses within 100 days.

Similarly, Moderna is developing an Omicron-specific booster version of its mRNA vaccine that could be ready for clinical testing in 60 to 90 days.

"From the beginning, we have said that, as we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves," Moderna chief executive Stephane Bancel said in a statement.

The company is also studying two "multivalent" boosters, which are designed to target common mutations seen across multiple variants. Those results are expected in coming weeks.

As well, Johnson & Johnson is pursuing an Omicron-specific version of its one-shot vaccine that, it says, will be progressed as needed.

"We will not be complacent," the company's global head of research and development, Dr Mathai Mammen, said in a statement.

How soon could Omicron boosters be available?
If modified vaccines prove necessary, the White House believes it could make them widely available within a few months.

That includes the time needed to develop and manufacture the doses, as well as obtaining necessary federal approvals.

"We are planning in that scenario not only for supporting the manufacturers through that process if needed, but also for how would we rapidly get shots in arms," White House coronavirus response coordinator Jeff Zients told a recent briefing.

"And we know how to do that, given the experience we've had the last year, and that is lessons learned about how we deployed the federal pharmacy programs, set up mass-vaccination sites, go to community health centres and rural clinics."

Boosters, Delta and the long winter ahead

In the US, Delta remains the dominant strain of COVID-19 and is leading a surge of cases going into winter.

The main things people can do to protect themselves — regardless of variants — are to get vaccinated, and wear masks indoors and in public places, according to Dr Gounder.

In countries where the option is available, she also recommends bolstering immunity with booster shots, particularly for the elderly and immunocompromised.

"What we've seen with prior immune-evading variants, like the Beta variant, is you could overcome that relative immune evasion by giving a booster dose of the currently available vaccines," she said.

"With respect to how quickly [or] how often new variants emerge, that is — to some degree — in our control.

"As long as we allow the virus to spread from person to person, every time it spreads from one person to another, it replicates and it has the opportunity to mutate."


New research finds vaccine only partially effective against Omicron

New research from South Africa suggests the highly-mutated Omicron variant can partially dodge protection from two doses of the Pfizer vaccine.

Alex Sigal, a professor at the Africa Health Research Institute, detailed some results from initial experiments on Twitter, revealing there was "a very large drop" in neutralisation of the Omicron variant relative to an earlier Covid strain.

Neutralising antibodies are an indicator of the body's immune response.

There are grave concerns about how well existing vaccines will work against the Omicron strain, as its spike proteins differ dramatically to the original coronavirus variant.

Results better than expected

But the study did offer some hope, showing blood from people who had received two doses of the vaccine and had a prior infection were mostly able to neutralise the variant.

This means booster doses could be key to stopping infections.

"These results are better than I expected. The more antibodies you've got, the more chance you'll be protected from Omicron," Sigal said on Twitter.

According to an official manuscript, which has not yet been peer reviewed, the lab tested blood from 12 people who had been vaccinated with two doses of the Pfizer-BioNTech vaccine.

Blood from five out of six people who had been vaccinated as well as previously infected with Covid-19 still neutralised the Omicron variant.

However, the lab has not tested the variant against blood from people who had received a booster dose as they are not yet available in South Africa.

The lab observed a 41-fold decline in levels of neutralising antibodies against the Omicron variant.

Sigal added the data will likely be adjusted as more experiments are completed.

There is no indication at this stage whether the vaccine is less able to prevent severe illness or death.

Scientists also believe other kinds of cells such as B-cells and T-cells, which are stimulated by the vaccines, could offer protection.

The Omicron variant, first detected in southern Africa last month, has triggered global alarm amid fears of another surge in infections.

The World Health Organisation classified Omicron on November 26 as a "variant of concern", but said there was no evidence to support the need for new vaccines.

There is not significant data yet on how other vaccines from Moderna, Johnson & Johnson and other drugmakers hold up against the new variant.




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