“In final analysis” of the study, “the Moderna Covid-19 vaccine showed 93% efficacy, with the efficacy remaining durable through six months after administration of the second dose,” Moderna said in a news release.
“We are pleased that our Covid-19 vaccine is showing durable efficacy of 93% through six months, but recognize that the Delta variant is a significant new threat so we must remain vigilant,” Moderna CEO Stéphane Bancel said in the news release.
Moderna says boosters may be needed before winter
Moderna believes the Delta variant will lead to more breakthrough infections, and that boosters may be needed before winter, according to slides published ahead of the company’s earnings call on Thursday.
“We believe that increased force of infection resulting from Delta, non-pharmaceutical intervention (NPI) fatigue, and seasonal effects (moving indoors) will lead to an increase of breakthrough infections in vaccinated individuals,” one of the slides says.
Moderna also said that while it sees durable efficacy of the vaccine, it expects neutralizing titers will continue to wane and eventually impact the efficacy of the vaccine.
“Given this intersection, we believe dose 3 booster will likely be necessary prior to the winter season,” a slide says.
Moderna is waiting for dosage data before filing for an emergency use authorization (EUA) for a booster shot, Moderna president Dr. Stephen Hoge said in Thursday’s investor call.
Moderna’s first two doses are 100 micrograms each. The company says it is exploring whether a booster — a third shot of the same vaccine — should be 50 micrograms or 100 micrograms.
“Our clinical data right now, we think, supports a 50-microgram … booster,” Hoge said. “But, we’re going to wait for 100-microgram data in the coming weeks to confirm the dose selection of 50 micrograms as the booster before filing.”
In Thursday’s call, Hoge presented early data, yet to be peer reviewed, showing the vaccine’s neutralizing antibodies waning six months after the second dose — including against the Delta variant.
Hoge said the yet-to-be-peer-reviewed data showed that 14 days after a 50-microgram booster was administered, antibody titers increased significantly.
Hoge called this “very encouraging,” adding that the company believes this confirms its selection of the booster as likely to be protective against circulating variants of concern, particularly Delta.
Experts have said it is unclear how these antibody levels correlate with real-world immunity, and to what extent other parts of the immune system — such as T cells — could factor into protection.
Pfizer said in an investor call last week that it intends to submit a booster for EUA consideration as early as August.
“You can see all from looking at the news that there are people and the jurisdictions that are actually taking things into their own hands. … FDA does not recommend taking things into your own hands,” said Marks in a discussion hosted by the Covid-19 Vaccine Education and Equity Project briefing.
The San Francisco health department maintains that it aligns with the CDC and FDA. “We are not recommending; we are accommodating requests,” Dr. Naveena Bobba, deputy director of health for SFDPH, said at a media briefing Tuesday. “We have gotten a few requests based on patients talking to their physicians and that’s why we are allowing for the accommodation.”
CNN’s Jacqueline Howard contributed to this report.