LAUSR

B.1.617.2 variant is characterized by several mutations in the genome, which increase immune evasion. Since neutralization strongly correlates with protection from symptomatic infection, neutralization resistance of this variant is of concern. Following the introduction of B.1.617.2 in Argentina, it was questioned whether its mutations would allow the virus to escape the neutralizing antibodies induced by vaccination and/or previous infection. Herein, we report our evaluation of the neutralizing potential of antibodies (NPA) against the SARS-CoV-2 B.1.617.2 variant elicited by natural infection and/or vaccination, compared to the ancestral wild type (WT) lineage B.1. We tested 309 plasma samples from individuals vaccinated with two doses of ChAdOx1-S, BBIBP-CorV or Gam-COVID-Vac with or without history of SARS-CoV-2 infection prior to vaccination (HIPV) and individuals unvaccinated and recovered from infection by ancestral WT-B.1. NPA achieved by vaccination with Gam-COVID-Vac, BBIBP-CorV and ChAdOx-1 against B.1.617.2 were significantly lower compared with ancestral WT-B.1. Nonetheless, we also showed that among individuals with HIPV, those immunized with BBIBP-CorV presented levels of NPA against ancestral WT B.1 significantly lower than unvaccinated individuals (GMT 5.35 and 6.42, respectively; p<0.001). Moreover, NPA against B.1.617.2 were not significantly different between these groups (GMT 3.42 and 3.80, respectively; p>0.05), suggesting that BBIBP-CorV appears not to be the most appropriate vaccine for individuals with HPIV. Our results indicate that, even significantly lower, NPA against SARS-CoV-2 B.1.617.2 variant elicited by natural infection and/or by immunization with vaccines widely used in developing countries were able to neutralize this variant. This article is protected by copyright. All rights reserved.