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Moderna has created a bivalent COVID-19 vaccine booster that it says provides a superior antibody response against the SARS-CoV-2 omicron variant and could be ready for distribution this fall.
“As we look to the fall infection season with respiratory viruses with SARS-CoV-2 and the ongoing circulation of omicron and its subvariants, we believe strongly that this data supports an update of the vaccine from the sequence we’ve been using from years ago to the bivalent omicron-containing booster demonstrated here,” Moderna President Stephen Hoge, M.D., said in a conference call Wednesday.
Moderna said the goal of its bivalent booster is to address waning neutralizing antibody titers and new variants as well as to improve durability of protection. The summary data announced in a press release come from a phase 2/3 study. They have not been formally published or peer reviewed.
Adults in the study previously received a Moderna vaccine primary series and one Moderna booster dose. As part of the trial, they were given a 50-microgram (µg) fourth dose of either the prototype booster or the new bivalent booster. The bivalent booster contains 25 µg of the prototype vaccine and 25 µg of an updated antigen against omicron.
The bivalent booster resulted in superior neutralizing geometric mean titers (GMT) against omicron compared to the prototype when looking at all participants as well as just those who were seronegative. The geometric mean ratio (GMR) was 1.78 when looking at all participants and 1.75 when looking at baseline seronegative participants. GMT against omicron increased roughly eight-fold above baseline after a bivalent booster.
The bivalent booster also met noninferiority criteria against the ancestral SARS-CoV-2 strain compared to the prototype booster with a GMR of 1.22 among all participants.
Among 437 participants, the bivalent booster was well-tolerated with side effects comparable to the prototype booster, according to Moderna. There were no vaccine-related serious adverse events.
The company plans to submit the data to the Food and Drug Administration (FDA) in the coming weeks and hopes to make the booster available in late summer or early fall. Health officials have said a fall booster may be necessary to protect against a potential winter surge.
The FDA’s Vaccines and Related Biological Products Advisory Committee will meet June 28 to discuss possible modification to the SARS-CoV-2 strains in COVID-19 vaccines. The meeting will not specifically be looking at Moderna’s new bivalent booster, but the company plans to provide a summary of its findings.
Moderna also hopes to receive emergency use authorization next week for its COVID-19 vaccines in children ages 6 months through 17 years. Those vaccines will be based on the original prototype vaccine being used in adults. However, the company said Wednesday it plans to study an omicron-containing bivalent primary series and boosters in children. It would be up to regulators and public health officials to determine if and when to update pediatric vaccines.
“We believe that our two-shot regimen here, which is simple, easy, very protective, is important now, if authorized, to get those kids vaccinated so they can get through the summer and then get back to school protected,” said Chief Medical Officer Paul Burton, M.D. “ … We can think about updating booster strategies in the later part of the year.”