Higher Delta variant-specific neutralizing antibodies prevented infection in close contacts vaccinated with ancestral mRNA vaccines during the SARS-CoV-2 Delta wave

• Published in: Scientific reports Vol. 13; no. 1; p. 19331
• Main Authors: Goh, Yun Shan, Fong, Siew-Wai, Tay, Matthew Zirui, Rouers, Angeline, Chang, Zi Wei, Chavatte, Jean-Marc, Hor, Pei Xiang, Loh, Chiew Yee, Huang, Yuling, Tan, Yong Jie, Wang, Bei, Ngoh, Eve Zi Xian, Mohd Salleh, Siti Nazihah, Lee, Raphael Tze Chuen, Lim, Georgina, Maurer-Stroh, Sebastian, Wang, Cheng-I, Leo, Yee-Sin, Lin, Raymond T P, Lam, Meng Chon, Lye, David C, Young, Barnaby Edward, Ng, Lisa F P, Renia, Laurent
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 07.11.2023; Nature Portfolio
• Subjects: Antibodies; Antibodies, Neutralizing; Antibodies, Viral; COVID-19; COVID-19 - prevention & control; COVID-19 vaccines; Dormitories; Humans; Immunization; Immunology; Infections; Infectious diseases; Living conditions; Medicine; mRNA; mRNA Vaccines; Public health; Quarantine; Risk factors; RNA, Messenger - genetics; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Vaccination
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-46800-x

Identification of the risk factors and the high-risk groups which are most vulnerable is critical in COVID-19 disease management at a population level. Evaluating the efficacy of vaccination against infections is necessary to determine booster vaccination strategies for better protection in high-risk groups. In this study, we recruited 158 mRNA-vaccinated individuals during the Delta wave of SARS-CoV-2 infections in Singapore and examined the antibody profiles of infected individuals. We found that, despite high exposure due to communal living conditions in proximity, 4% of individuals (6/158) had PCR-confirmed infections and 96% (152/158) remained uninfected. Time-course analysis of the antibody profile at the start and the end of quarantine period showed Delta-specific boosting of anti-spike antibody response in 57% of the uninfected individuals (86/152). In the remaining 43% of the uninfected individuals (66/152) with no Delta-specific antibody boost, we found a higher Delta-specific antibody response at the start of quarantine period, which correlated with higher Delta pseudovirus neutralizing capacity. Our findings indicate that a higher basal variant-specific antibody response in the mRNA-vaccinated individuals contributes to better protection against infections by the new emerging SARS-CoV-2 variants.