Moderna's Omicron-targeted booster shot shows promise

Moderna COVID vaccine supplies
Moderna COVID vaccine supplies

Anthony Quintano / Flickr cc

Ahead of a Food and Drug Administration (FDA) meeting later this month to discuss updated COVID-19 vaccine strategies, Moderna today announced that its bivalent COVID booster candidate prompted higher antibody response against the Omicron variant than the current version of the company's mRNA vaccine.

In other developments, White House officials signaled today that they will shift $10 billion away from some parts of the COVID-19 response to allow the government to buy vaccines and treatments, and the World Health Organization (WHO) said global cases continue to fall, though more transmissible subvariants are gaining a bigger toehold.

Vaccine boosts Omicron antibodies 8-fold

In a statement, Moderna said its Omicron-containing bilvalent (two-strain) vaccine met clinical end points, including a better antibody response 1 month after vaccination compared to its original vaccine. Like the original Moderna booster dose, the dose for the bivalent version was 50 micrograms.

The geometric mean titer (GMT), a measure of antibody response, was 2,372 for the bivalent vaccine against Omicron, compared with 1,473 for the original Moderna vaccine. The newer version boosted GMT against Omicron about eightfold higher than baseline levels.

The company said the bivalent vaccine was generally well tolerated, with side effects similar to its current booster dose. It also said it anticipates that antibody titers induced by the bivalent vaccine will be more durable against Omicron compared to its current booster shot. The results were from a small trial that had 439 participants.

Moderna said it plans on submitting the interim analysis and data to regulators to review in the weeks ahead. The Food and Drug Administration (FDA) vaccine advisory group, the Vaccines and Related Biological Products Advisory Committee (VRBPAC) meets on Jun 28 to talk about if and how COVID-19 vaccines should be modified.

Shifting COVID resources

In a related development, due to an ongoing stalemate over the Biden administration's $22.5 billion request for emergency aid to support the ongoing COVID-19 response, including potential purchases of updated vaccine, White House officials today signaled that they will shift $10 billion in current funding, according to the Washington Post.

An unnamed official said the government would redirect $5 billion in existing funds to buy new vaccines if they become available and will repurpose $5 billion in previously approved aid to buy treatments, including Pfizer's COVID-19 antiviral drug Paxlovid.

The $10 billion shift in resources will come from programs to ensure a supply of COVID-19 tests, efforts to stockpile ventilators and personal protective equipment, and Department of Health and Human Services research programs on coronavirus vaccines and treatments, according to the Post.

Reinfections and response strategies

In other US developments:

  • More than 1.6 million COVID-19 reinfections have been reported in 24 states since data collection started, according to an analysis from ABC News. New York, California, and Maine each reported about 200,000 reinfections.

  • Some states are transitioning their COVID-19 responses to a more endemic stance. For example, Rhode Island yesterday announced an endemic strategy for testing and vaccination, shifting testing and vaccination to existing public health infrastructure. State-run vaccination services will be available through Jun 30, though officials added that if demand increases and outpaces health capacity, they are prepared to stand up the state-run sites again. Similarly, the state said it will transition testing to normal healthcare channels and self-testing, again with an option to reopen mass testing sites if community levels are high.

  • In Alaska, health officials this week said they will rescind the COVID-19 public health emergency order on Jul 1, according to KTOO, the state's public radio station. Officials said they will continue to offer COVID-19 services and track data. The Jul 1 end of the order coincides with a decrease in federal reimbursement for COVID-19 spending and will end extra Supplemental Nutrition Assistance Program benefits for households that were receiving them.

  • The 7-day average for new daily COVID-19 cases is 112,771, with 326 daily deaths, according to the New York Times tracker. The nation's cases have slowly been trending upward since the middle of April, driven by more transmissible Omicron subvariant activity, with areas reporting the highest cases recently shifting roughly from east to west.

Global cases fall but subvariants gain ground

In its weekly pandemic update today, the World Health Organization (WHO) said global COVID-19 activity continues to fall after peaking in January. Last week, cases fell 12% and deaths declined 22% compared with the previous week.

Cases increased in two WHO regions, however. The Eastern Mediterranean saw a rise of 19%, mainly led by modest rises in Saudi Arabia, Bahrain, and the United Arab Emirates. Somalia and Morocco had the region's largest proportional increases. In Southeast Asia, cases rose 1% last week, mainly due to rises in India, Indonesia, and Nepal.

At a WHO briefing, Director-General Tedros Adhanom Ghebreyesus, PhD, said the trends are encouraging and show that vaccination is saving lives. He urged caution, however, owing to gaps in testing and vaccination.

He said the WHO and its partners are working with countries, especially those with lower vaccination rates, to improve uptake by getting the vaccine to where people are.

Tedros said the perception that the pandemic is over is understandable but misguided, because of ongoing threats from emerging variants and lagging vaccination levels in many countries. "The pandemic is not over, and we will keep saying it's not over until it is," he said.

The WHO noted that three Omicron subvariants are becoming more prevalent, with BA.2.12.1—first identified in New York—present in 53 countries and making up 28% of sequenced samples. BA.5 and BA.4 make up 4% and 2% of circulating variants, respectively, and are in 47 and 42 countries, respectively.

The WHO notes that all three carry mutations linked to higher transmissibility and immune escape. So far, no increases in severity have been seen with BA.5 and BA.4, with no evidence yet on severity with BA.2.12.1.

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