Antibody evolution to SARS-CoV-2 after single-dose Ad26.COV2.S vaccine in humans
Alice Cho, Frauke Muecksch, Zijun Wang, Tarek Ben Tanfous, Justin DaSilva, Raphael Raspe, Brianna Johnson, Eva Bednarski, Víctor Ramos, Dennis Schaefer-Babajew, Irina Shimeliovich, Juan Dizon, Kai-Hui Yao, Fabian Schmidt, Katrina G. Millard, Martina Turroja, Mila Janković, Thiago Y. Oliveira, Anna Gazumyan, Christian Gaebler, Marina Caskey, Théodora Hatziioannou, Paul D. Bieniasz, Michel C. Nussenzweig
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.