Moderna: Blood samples show vaccine effective against delta variant

The coronavirus vaccine developed by U.S. biotech firm Moderna is effective against emerging mutations including the highly contagious delta variant, the company announced Tuesday.

According to Moderna, blood samples from fully vaccinated individuals produced antibodies against multiple variants, measuring a "minimal impact on neutralizing titers against the alpha and A.23.1 variants" and a "modest reduction in neutralizing titers" against the delta, gamma, kappa and and eta variants. 

"As we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves. We remain committed to studying emerging variants, generating data and sharing it as it becomes available. These new data are encouraging and reinforce our belief that the Moderna COVID-19 Vaccine should remain protective against newly detected variants," said Stéphane Bancel, chief executive officer of Moderna. "These findings highlight the importance of continuing to vaccinate populations with an effective primary series vaccine."

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The study was released on the heels of another study published Monday in the journal Nature which found evidence that the vaccines, including Pfizer and Moderna, induced strong, persistent immunity to COVID-19. The evidence suggests that many who have already received either vaccine may not need a booster shot, as long as the coronavirus and its variants do not significantly evolve and render the vaccines ineffective.

Even so, Moderna continues to pursue a clinical development strategy against emerging variants, and is also studying mRNA-1273.211, a multivalent booster candidate which combines a 50-50 mix of mRNA-1273, Moderna’s authorized vaccine against ancestral strains, and mRNA-1273.351 in a single vaccine at several dose levels in an ongoing study.

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The Moderna COVID-19 vaccine is authorized for under an emergency use authorization for active immunization to prevent COVID-19 in individuals 18 years of age and older.

As of Wednesday, 66.5% of American adults have received at least one dose of a COVID-19 vaccine — a small margin from President Joe Biden’s goal of 70% by the July 4th holiday. 

Meanwhile, 57.4% of adults have received at least one dose, according to data from the Centers for Disease Control and Prevention.

This story was reported from Los Angeles.