How vaccine companies are responding to Omicron

Matt Woodley

29/11/2021 5:28:47 PM

Scientists are scrambling to test and potentially update their vaccine candidates against the latest COVID variant of concern.

Vaccine laboratory worker.
Companies are conducting laboratory tests to ascertain whether Omicron reduces vaccine efficacy.

The B.1.1.529 variant of concern – dubbed ‘Omicron’ by the World Health Organization – has the world on high alert due to reports it could be up to five times more infectious than the now-dominant Delta, which was already around three times more infectious than the original strain.
But those are not the only changes to this new strain that has scientists worried. With more than 50 mutations, including over 30 to the spike protein, there are also concerns Omicron could reduce the efficacy of existing vaccines.
So how are companies responding?
About 24 million doses of the Pfizer COVID vaccine have been administered in Australia, around double the nearest competitor (AstraZeneca) and 24 times more than Moderna.
The company is also likely to supply the vast majority of doses for Australia’s booster program, with the Federal Government agreeing to purchase at least another 85 million doses.
Over the weekend, BioNtech – the company Pfizer has partnered with to produce its COVID vaccines – indicated it will be about two weeks before laboratory experiments conducted by researchers can determine whether the current vaccine is sufficiently effective against Omicron.
‘Pfizer and BioNTech have taken actions months ago to be able to adapt the mRNA vaccine within six weeks and ship initial batches within 100 days in the event of an escape variant,’ the company said.
‘We understand the concern of experts and have immediately initiated investigations on variant B.1.1.529
‘These data will provide more information about whether B.1.1.529 could be an escape variant that may require an adjustment of our vaccine.’
The Spikevax Moderna vaccine has also been earmarked to likely play a large role in Australia’s booster rollout, pending approval by the Therapeutic Goods Administration (TGA).
Part of Australia’s 25 million-dose agreement with the company includes access to 15 million doses of ‘variant-specific versions’ to address longer-term immunity and viral variants, which should be available in the first half of 2022.
A press release issued by the company over the weekend described how Omicron includes mutations seen in the Delta variant that are ‘believed to increase transmissibility’, and mutations seen in the Beta and Delta variants that are ‘believed to promote immune escape’.
‘The combination of mutations represents a significant potential risk to accelerate the waning of natural and vaccine-induced immunity,’ the press release states.
‘The company is working rapidly to test the ability of the current vaccine dose to neutralise the Omicron variant and data is expected in the coming weeks.
‘Since early 2021, Moderna has advanced a comprehensive strategy to anticipate new variants of concern. This strategy includes three levels of response should the currently authorised 50 µg booster dose of mRNA-1273 prove insufficient to boost waning immunity against the Omicron variant.’
The first part of Moderna’s strategy included testing a higher-dose booster (100 µg) in 306 healthy adults, which generally resulted in the highest neutralising titers against prior SARS-CoV-2 strains.
It also has already two multi-valent booster candidates designed to anticipate mutations, such as those that have emerged in the Omicron variant. 
‘The first candidate [mRNA-1273.211] includes several mutations present in the Omicron variant that were also present in the Beta variant of concern,’ Moderna states.
‘A second multi-valent candidate [mRNA-1273.213] includes many of the mutations present in the Omicron variant that were also present in the Beta and Delta variants.
‘Moderna will rapidly expand testing of sera from completed and ongoing multi-valent booster studies to determine if these multi-valent candidates are able to provide superior neutralising protection against Omicron.’
It has also stated it will ‘rapidly advance’ an Omicron-specific booster candidate (mRNA-1273.529), which based on prior experience should be available for clinical testing in the next 60–90 days.
Although yet to be approved for use in Australia, Novavax has an agreement in place to supply around 51 million doses, which will likely be incorporated into next year’s booster rollout.
The company has reportedly already begun working on an updated vaccine to target the Omicron variant, which it says will be ready for testing and manufacturing in the next few weeks.
The subunit vaccine contains an actual version of the virus’ spike protein that cannot cause disease but can trigger the immune system, and Novavax says it has started developing a spike protein specifically based on the known genetic sequence of B.1.1.529.
The initial work will ‘take a few weeks’, a company spokesperson said.
While unlikely to be a part of Australia’s booster rollout, it remains important to understand the level of protection afforded against Omicron by a standard two-dose regimen of AZD-1222.
Australia is also only roughly halfway through producing the 50 million doses of the vaccine it has agreed to manufacture domestically, the vast majority of which are likely to be sent overseas.
AstraZeneca has indicated that it is already conducting research in Botswana and Eswatini, where the variant has been identified, to collect real-world data on how the vaccine performs against Omicron.
The company emphasises that its vaccine has been effective against all prior SARS-CoV-2 variants of concern. However, it has not provided a timeframe as to when data on efficacy against Omicron will be released.
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AstraZeneca B.1.1.529 COVID-19 Moderna Novavax Omicron Pfizer vaccines variant of concern

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