{'fraction_non_alphanumeric': 0.043557168784029036, 'fraction_numerical': 0.030399274047186932, 'mean_word_length': 5.318051575931232, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
SARS-CoV-2 vaccination of convalescents boosts neutralization capacity against SARS-CoV-2 Delta and Omicron that can be predicted by anti-S antibody concentrations in serological assays

Background : Recent data on immune evasion of new SARS-CoV-2 variants raise concerns about antibody-based COVID-19 therapies. Therefore in this study the in-vitro neutralization capacity against SARS-CoV-2 variants Wuhan D614G, Delta and Omicron in sera of convalescent individuals with and without boost by vaccination was assessed. Methods and Findings: This in-vitro study included 66 individuals with a history of SARS-CoV-2 infection, divided into subgroups without (n=29) and with SARS-CoV-2 vaccination (n=37). We measured SARS-CoV-2 antibody concentrations by serological assays (anti-SARS-CoV-2-QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S) and neutralizing titers against Wuhan D614G, Delta and Omicron in a pseudovirus neutralization assay. Sera of the majority of unvaccinated convalescents did not effectively neutralize Delta and Omicron (4/29, 13.8% and 19/29, 65.5%, resp.). Neutralizing titers against Wuhan D614G, Delta and Omicron were significantly higher in vaccinated compared to unvaccinated convalescents (p<0.0001) with 11.1, 15.3 and 60-fold higher geometric mean of 50%-neutralizing titers (NT50) in vaccinated compared to unvaccinated convalescents. The increase in neutralizing titers was already achieved by one vaccination dose. Neutralizing titers were highest in the first 3 months after vaccination. Concentrations of anti-S antibodies in the serological assays anti-SARS-CoV-2 QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S predict neutralization capacity against Wuhan D614G, Delta and Omicron. While Wuhan D614G was neutralized in-vitro by Bamlanivimab, Casirivimab and Imdevimab, Omicron was resistant to these monoclonal antibodies. Conclusions: These findings confirm substantial immune evasion of Delta and Omicron which can be overcome by vaccination of convalescents. This informs strategies for choosing of plasma donors in COVID-19 convalescent plasma programs that shall select specifically vaccinated convalescents with very high titers of anti-S antibodies.