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Published on: June 5, 2021
Antibody evolution to SARS-CoV-2 after single-dose Ad26.COV2.S vaccine in humans
Alice Cho1, Frauke Muecksch2, Zijun Wang1
1Laboratory of Molecular Immunology, The Rockefeller University, New York, NY.
Abstract:
The single-dose Ad.26.COV.2 (Janssen) vaccine elicits lower levels of neutralizing antibodies and shows more limited efficacy in protection against infection than either of the two available mRNA vaccines. In addition, Ad.26.COV.2 has been less effective in protection against severe disease during the Omicron surge. Here, we examined the memory B cell response to single-dose Ad.26.COV.2 vaccination. Compared with mRNA vaccines, Ad.26.COV.2 recipients had significantly lower numbers of RBD-specific memory B cells 1.5 or 6 mo after vaccination. Despite the lower numbers, the overall quality of the memory B cell responses appears to be similar, such that memory antibodies elicited by both vaccine types show comparable neutralizing potency against SARS-CoV-2 Wuhan-Hu-1, Delta, and Omicron BA.1 variants. The data help explain why boosting Ad.26.COV.2 vaccine recipients with mRNA vaccines is effective and why the Ad26.COV2.S vaccine can maintain some protective efficacy against severe disease during the Omicron surge.
Insights
The Janssen Ad.26.COV.2 vaccine generates fewer memory B cells than mRNA vaccines, but these cells still offer comparable protection against SARS-CoV-2 variants. This explains why mRNA boosters are effective for Ad.26.COV.2 recipients.
Area of Science:
- Immunology
- Vaccinology
- Virology
Background:
- The single-dose Ad.26.COV.2 (Janssen) vaccine shows lower neutralizing antibody levels and reduced efficacy against SARS-CoV-2 infection and severe disease, particularly during the Omicron surge, compared to mRNA vaccines.
- Understanding the memory B cell response is crucial for evaluating vaccine effectiveness and informing booster strategies.
Purpose of the Study:
- To investigate the memory B cell response following a single dose of the Ad.26.COV.2 vaccine.
- To compare the quantity and quality of memory B cell responses elicited by Ad.26.COV.2 vaccination versus mRNA vaccines.
Main Methods:
- Analysis of memory B cell populations in Ad.26.COV.2 vaccine recipients at 1.5 and 6 months post-vaccination.
- Comparison of RBD-specific memory B cell numbers and neutralizing antibody potency against SARS-CoV-2 variants (Wuhan-Hu-1, Delta, Omicron BA.1) between Ad.26.COV.2 and mRNA vaccine groups.
Main Results:
- Ad.26.COV.2 recipients exhibited significantly lower numbers of RBD-specific memory B cells compared to mRNA vaccine recipients at both 1.5 and 6 months post-vaccination.
- Despite quantitative differences, the quality of memory B cell responses was comparable, with elicited memory antibodies showing similar neutralizing potency against SARS-CoV-2 Wuhan-Hu-1, Delta, and Omicron BA.1 variants.
Conclusions:
- The Ad.26.COV.2 vaccine elicits a lower quantity but comparable quality of memory B cell response relative to mRNA vaccines.
- These findings support the effectiveness of mRNA vaccine boosting in Ad.26.COV.2 recipients and explain the vaccine's retained protective efficacy against severe disease during Omicron surges.
