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mRNA bivalent booster enhances neutralization against BA.2.75.2 and BQ.1.1
Biorxiv : the Preprint Server for Biology
|November 16, 2022
Summary
The bivalent COVID-19 mRNA booster vaccine shows improved immune response against Omicron subvariants compared to monovalent boosters. This enhanced vaccine broadens humoral immunity, offering better protection against emerging SARS-CoV-2 variants.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- Emergence of SARS-CoV-2 Omicron variants, including subvariants with mutations like R346T, has reduced the effectiveness of ancestral spike-based vaccines.
- The bivalent COVID-19 mRNA booster vaccine in the US combines ancestral and Omicron BA.5 spike components.
- New Omicron subvariants (BA.2.75.2, BQ.1.1) possess spike protein mutations potentially evading vaccine-induced immunity.
Approach:
- Live virus neutralization assays were performed using serum samples from individuals who received monovalent or bivalent COVID-19 mRNA boosters.
- Neutralizing activity was assessed against the ancestral SARS-CoV-2 strain (WA1/2020) and Omicron subvariants (BA.1, BA.5, BA.2.75.2, BQ.1.1).
Key Points:
- Monovalent boosters showed significant reductions in neutralization titers (9-39 fold) against Omicron subvariants compared to ancestral virus.
- The bivalent booster demonstrated improved neutralizing activity against all tested Omicron subvariants.
- Reductions in neutralization titers for the bivalent booster were 3.7-4 fold for BA.1/BA.5 and 11.5-21 fold for BA.2.75.2/BQ.1.1 relative to ancestral virus.
Conclusions:
- The BA.5-containing bivalent mRNA booster vaccine broadens humoral immunity against currently circulating Omicron subvariants.
- This suggests enhanced protection against diverse SARS-CoV-2 Omicron lineages.
