Project description:BackgroundSARS-CoV-2 vaccines currently authorized for emergency use have been highly successful in preventing infection and lessening disease severity. The vaccines maintain effectiveness against earlier SARS-CoV-2 Variants of Concern but the heavily mutated, highly transmissible Omicron variant presents an obstacle both to vaccine protection and monoclonal antibody therapies.MethodsPseudotyped lentiviruses were incubated with serum from vaccinated and boosted donors or therapeutic monoclonal antibody and then applied to target cells. After 2 days, luciferase activity was measured in a microplate luminometer. Resistance mutations of the Omicron spike were identified using point-mutated spike protein pseudotypes and mapped onto the three-dimensional spike protein structure.FindingsVirus with the Omicron spike protein was 26-fold resistant to neutralization by recovered donor sera and 26-34-fold resistance to Pfizer BNT162b2 and Moderna vaccine-elicited antibodies following two immunizations. A booster immunization increased neutralizing titres against Omicron. Neutralizing titres against Omicron were increased in the sera with a history of prior SARS-CoV-2 infection. Analysis of the therapeutic monoclonal antibodies showed that the Regeneron and Eli Lilly monoclonal antibodies were ineffective against the Omicron pseudotype while Sotrovimab and Evusheld were partially effective.InterpretationThe results highlight the benefit of a booster immunization to protect against the Omicron variant and demonstrate the challenge to monoclonal antibody therapy. The decrease in neutralizing titres against Omicron suggest that much of the vaccine efficacy may rely on T cells.FundingThe work was funded by grants from the NIH to N.R.L. (DA046100, AI122390 and AI120898) and 55 to M.J.M. (UM1AI148574).
Project description:Heterologous SARS-CoV-2 vaccine approaches with a second mRNA-based vaccine have been favored in the recommendations of many countries over homologous vector-based ChAdOx1 nCoV-19 vaccination after reports of thromboembolic events and lower efficacy of this regimen. In the middle of 2021, the SARS-CoV-2 Delta variant of concern (VoC) has become predominant in many countries worldwide. Data addressing the neutralization capacity of a heterologous ChAdOx1 nCoV-19/mRNA-based vaccination approach against the Delta VoC in comparison to the widely used homologous mRNA-based vaccine regimen are limited. Here, we compare serological immune responses of a cohort of ChAdOx1 nCoV-19/BNT162b2-vaccinated participants with those of BNT162b2/BNT162b2 vaccinated ones and show that neutralization capacity against the Delta VoC is significantly increased in sera of ChAdOx1 nCoV-19/BNT162b2-vaccinated participants. This overall effect can be attributed to ChAdOx1 nCoV-19/BNT162b2-vaccinated women, especially those with more severe adverse effects leading to sick leave following second immunization.
Project description:Rapidly spreading variants of SARS-CoV-2 that have arisen in the United Kingdom and South Africa share the spike N501Y substitution, which is of particular concern because it is located in the viral receptor binding site for cell entry and increases binding to the receptor (angiotensin converting enzyme 2). We generated isogenic N501 and Y501 SARS-CoV-2. Sera of 20 participants in a previously reported trial of the mRNA-based COVID-19 vaccine BNT162b2 had equivalent neutralizing titers to the N501 and Y501 viruses.
Project description:Rapidly spreading variants of SARS-CoV-2 that have arisen in the United Kingdom and South Africa share the spike N501Y substitution, which is of particular concern because it is located in the viral receptor binding site for cell entry and increases binding to the receptor. We generated isogenic N501 and Y501 SARS-CoV-2. Twenty human sera from the mRNA-based vaccine BNT162b2 trial exhibited equivalent neutralizing titers to the N501 and Y501 viruses.
Project description:Initial COVID-19 vaccine candidates were based on the original sequence of SARS-CoV-2. However, the virus has since accumulated mutations, among which the spike D614G is dominant in circulating virus, raising questions about potential virus escape from vaccine-elicited immunity. Here, we report that the D614G mutation modestly reduced (1.7-2.4-fold) SARS-CoV-2 neutralization by BNT162b2 vaccine-elicited mouse, rhesus, and human sera, concurring with the 95% vaccine efficacy observed in clinical trial.
Project description:The globally circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern Omicron (B.1.1.529) has a large number of mutations, especially in the spike protein, indicating that recognition by neutralizing antibodies may be compromised. We tested Wuhan (Wuhan-Hu-1 reference strain), Beta (B.1.351), Delta (B.1.617.2), or Omicron pseudoviruses with sera of 51 participants who received two or three doses of the messenger RNA (mRNA)-based COVID-19 vaccine BNT162b2. After two doses, Omicron-neutralizing titers were reduced >22-fold compared with Wuhan-neutralizing titers. One month after the third vaccine dose, Omicron-neutralizing titers were increased 23-fold relative to their levels after two doses and were similar to levels of Wuhan-neutralizing titers after two doses. The requirement of a third vaccine dose to effectively neutralize Omicron was confirmed with sera from a subset of participants using live SARS-CoV-2. These data suggest that three doses of the mRNA vaccine BNT162b2 may protect against Omicron-mediated COVID-19.
Project description:Highly transmissible SARS-CoV-2 variants identified in India and designated B.1.617, Kappa (B.1.617.1), Delta (B.1.617.2), B.1.618, and B.1.36.29 contain spike mutations L452R, T478K, E484K, E484Q, and N440K located within the spike receptor-binding domain and thus could contribute to increased transmissibility and potentially allow re-infection or cause resistance to vaccine-elicited antibody. To address these issues, we used lentiviruses pseudotyped by variant spikes to measure their neutralization by convalescent sera, vaccine-elicited and Regeneron therapeutic antibodies, and ACE2 affinity. Convalescent sera and vaccine-elicited antibodies neutralized viruses with Delta spike with 2- to 5-fold decrease in titer in different donors. Regeneron antibody cocktail neutralized virus with the Delta spike with a 2.6-fold decrease in titer. Neutralization resistance to serum antibodies and monoclonal antibodies was mediated by L452R mutation. These relatively modest decreases in antibody neutralization titer for viruses with variant spike proteins suggest that current vaccines will remain protective against the family of Delta variants.