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Booster of mRNA-1273 Strengthens SARS-CoV-2 Omicron Neutralization
Nicole A Doria-Rose1, Xiaoying Shen2, Stephen D Schmidt1
1Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
Abstract:
The Omicron variant of SARS-CoV-2 is raising concerns because of its increased transmissibility and potential for reduced susceptibility to antibody neutralization. To assess the potential risk of this variant to existing vaccines, serum samples from mRNA-1273 vaccine recipients were tested for neutralizing activity against Omicron and compared to neutralization titers against D614G and Beta in live virus and pseudovirus assays. Omicron was 41-84-fold less sensitive to neutralization than D614G and 5.3-7.4-fold less sensitive than Beta when assayed with serum samples obtained 4 weeks after 2 standard inoculations with 100 μg mRNA-1273. A 50 μg boost increased Omicron neutralization titers and may substantially reduce the risk of symptomatic vaccine breakthrough infections.
Insights
The Omicron variant of SARS-CoV-2 shows reduced neutralization by mRNA-1273 vaccine sera. A booster dose significantly increases neutralizing titers against Omicron, potentially lowering breakthrough infection risk.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- The SARS-CoV-2 Omicron variant exhibits increased transmissibility and potential immune evasion.
- Concerns exist regarding the effectiveness of existing vaccines against Omicron.
- Assessing vaccine-induced neutralization is critical for public health strategies.
Approach:
- Serum samples from mRNA-1273 vaccine recipients were analyzed.
- Neutralizing activity against Omicron, D614G, and Beta variants was measured.
- Live virus and pseudovirus assays were employed to compare neutralization titers.
Key Points:
- Omicron showed 41-84-fold reduced neutralization compared to D614G.
- Omicron was 5.3-7.4-fold less sensitive to neutralization than Beta.
- Serum samples were collected 4 weeks post-primary mRNA-1273 vaccination (100 μg).
Conclusions:
- A 50 μg mRNA-1273 booster dose significantly enhanced Omicron neutralization titers.
- Booster vaccination may substantially mitigate the risk of symptomatic Omicron breakthrough infections.
- Further research is needed to fully understand long-term protection and variant evolution.
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