As unnerving as the SARS-CoV-2 variant might be, pharmacists have every reason to expect that vaccines to address any gaps in coverage will be available quickly.

Moderna quickly announced updates to its strategy to combat SARS-CoV-2 variants of concern, given the emergence of the Omicron variant.

Recent descriptions of the Omicron variant raised concerns about heightened transmissibility and immune escape. "The combination of mutations represents a significant potential risk to accelerate the waning of natural and vaccine-induced immunity," Moderna cautioned in a press release. "A booster dose of an authorized vaccine represents the only currently available strategy for boosting waning immunity. The Moderna COVID-19 vaccine (mRNA-1273) is authorized as a booster for many populations at the 50 µg dose level."

The press release adds that the company is working quickly to test the ability of the current vaccine dose to neutralize the Omicron variant, with data expected in the coming weeks. Since early 2021, Moderna has had a strategy to anticipate new variants of concern. In this case, three levels of response would be activated if the currently authorized 50-mcg booster dose of mRNA-1273 is shown to be insufficient to boost waning immunity against the Omicron variant.

A higher booster dose of mRNA-1273 (100 mcg) has already been tested in healthy adults. Moderna currently is testing sera from its high-dose booster recipients in neutralizing assays to determine if the 100-mcg dose provides superior neutralizing protection against Omicron.

Two multivalent booster candidates are already being studied that were 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. A second multivalent candidate (mRNA-1273.213) also includes many of the mutations present in the Omicron variant that were also present in the Beta and Delta variants.

An Omicron-specific booster candidate (mRNA-1273.529) is being developed. Part of Moderna's strategy to advance variant-specific candidates for a subset of variants of significant concern, and Beta- and Delta-specific boosters were already issued in 2021.

"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. The mutations in the Omicron variant are concerning and for several days, we have been moving as fast as possible to execute our strategy to address this variant," said Stéphane Bancel, chief executive officer of Moderna.

Pfizer, meanwhile, advises it will be able to manufacture and distribute an updated version of its COVID-19 vaccine within 100 days if the new variant Omicron is found to be resistant to its current vaccine.

"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 in a statement.

Pfizer expects to know within 2 weeks whether the variant is resistant to its current vaccine, a company spokesperson told the news media.

Worries about Omicron rippled through business, healthcare, and political circles. President Joe Biden said he was "...briefed by my chief medical advisor, Dr. Tony Fauci, and the members of our COVID response team, about the Omicron variant, which is spreading through Southern Africa. As a precautionary measure, until we have more information, I am ordering additional air travel restrictions from South Africa and seven other countries. These new restrictions will take effect on November 29. As we move forward, we will continue to be guided by what the science and my medical team advises."

The World Health Organization (WHO), meanwhile, reported on the meeting of the Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE), which is an independent group of experts that periodically monitors and evaluates the evolution of SARS-CoV-2 and tries to determine if specific mutations and combinations of mutations alter how the virus behaves. A recent meeting was on SARS-CoV-2 variant: B.1.1.529, called Omicron, which was first reported to the WHO from South Africa on November 24.

"This variant has a large number of mutations, some of which are concerning," the WHO notes. "Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other [variants of concern]. The number of cases of this variant appears to be increasing in almost all provinces in South Africa."

The agency advises that current SARS-CoV-2 PCR diagnostics are able to detect the variant. Because in one widely used PCR test one of the three target genes is not detected—S gene dropout or S gene target failure—the test therefore can be used as a marker for the Omicron variant, pending sequencing confirmation. "Using this approach, this variant has been detected at faster rates than previous surges in infection, suggesting that this variant may have a growth advantage," the WHO notes.

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