Moderna Says Studies Show Its Vaccine Is Effective Against The Delta Variant

Studies have found that Moderna's COVID-19 vaccine is effective against several variants of concern, including the delta variant, the biotech company announced.

Moderna said Tuesday that recently completed studies have found the vaccine to have a neutralizing effect against all COVID-19 variants tested, including the beta, delta, eta and kappa variants.

While still highly effective against the delta variant, the study showed the vaccine was less effective against it and certain other variants than against the original strain of the virus.

The antibody response against the delta variant was about two times weaker than against the ancestral strain of the virus.

The news echoes other findings that the Moderna and Pfizer vaccines are highly effective against the delta variant. A study published this month in Nature found that Pfizer's vaccine was able to neutralize variants including delta, though at somewhat reduced strength.

"These new data are encouraging and reinforce our belief that the Moderna COVID-19 Vaccine should remain protective against newly detected variants," Stéphane Bancel, Moderna's chief executive officer, said in a statement. "These findings highlight the importance of continuing to vaccinate populations with an effective primary series vaccine."

The company also said it is developing a booster candidate: a 50-50 mix of its currently authorized COVID-19 vaccine and another messenger RNA vaccine it has developed.

The delta variant is spreading fast

The delta variant is the fast-moving form of the coronavirus that is now found in 96 countries, including the United States.

Last week, Dr. Anthony Fauci of the National Institutes of Health said the delta variant is "currently the greatest threat in the U.S. to our attempt to eliminate COVID-19," noting that the proportion of infections being caused by the variant is doubling every two weeks.

The delta variant is now infecting at least 1 out of every 5 people who get the virus in the United States. In some sections of the country, the variant is already far more common, particularly in parts of the Midwest and West. At its current pace, the delta variant is expected to be the dominant virus in the U.S. within weeks.

Dr. Maria Van Kerkhove, an infectious disease expert at the World Health Organization, called the delta variant "incredibly transmissible."

"These viruses are becoming more fit. The virus is evolving, and this is natural," she told NPR's Morning Edition. "It's more transmissible than the alpha variant, so we need to just do all we can to prevent as many infections as we can and do what we can do to reduce the spread."

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