A bivalent Moderna vaccine has been shown to produce a potent neutralising antibody response against the Omicron sub-variants BA.4 and BA.5
According to the results of a press release a bivalent Moderna vaccine has been shown to generate a large neutralising antibody response against two of the Omicron sub-variants, BA.4 and BA.5.
The BA.4 and BA.5 sub-variants of Omicron were first detected in South Africa in January and February 2022, respectively. These sub-variants have become a cause for concern after a study published in the New England Journal of Medicine, found that the sub-variants, substantially escaped neutralising antibodies induced by both vaccination and infection. The study reported that among individuals who had received a third (i.e., booster) dose of BNT162b, compared with the response against the original COVID-19 isolate, the neutralising antibody titre was lower by a factor of 21 against BA.4 or BA.5. In short, it seems highly likely that even among those who have been fully vaccinated, the BA.4 and BA.5 can lead to re-infection.
The bivalent Moderna vaccine has been studied in a phase 2 and phase 3 trial in which all participants who had previously received 2 or 3 doses of an approved COVID-19 vaccine. Participants were then given mRNA-1273.529, mRNA-1273.214, or mRNA-1273 and participants who have previously received a primary series and 1 booster dose were to receive either mRNA-1273.529, mRNA-1273.214, or mRNA-1273 as the 4th dose.
Bivalent Moderna vaccine and Omicron sub-variants
According to the press release, for the COVID booster candidate, mRNA-1273.214, one month after administration in previously boosted participants, a 50 µg booster dose elicited potent neutralising antibody responses against the Omicron sub-variants BA.4 and BA.5 in all participants. In fact, mRNA-1273.214 increased neutralising titres against BA.4/BA.5 by 5.4-fold (95% CI 5.0 – 5.9) above baseline in all participants regardless of prior infection and by 6.3-fold (95% CI 5.7 – 6.9) in the subset of seronegative participants.
These results follow on from the data in a press release in early June 2022, in which Moderna announced that a booster dose with mRNA-1273.214 increased neutralising geometric mean titres (GMT) against the Omicron variant by approximately 8-fold above baseline levels. Moreover, a 50 μg booster dose of mRNA-1273.214 was well-tolerated in the 437 study participants and both the safety and reactogenicity profile of mRNA-1273.214 was similar to that of mRNA-1273 when these vaccines were administered as a second booster dose.
As a result of these findings, the manufacturer is now working to complete regulatory submissions in the coming weeks requesting to update the composition of the booster vaccine to mRNA-1273.214.
