ORCID Profile
0000-0002-0003-541X
Current Organisation
National Centre for Infectious Diseases
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Publisher: Elsevier BV
Date: 04-2022
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 10-2021
Publisher: EDP Sciences
Date: 05-2012
Publisher: American Society for Microbiology
Date: 25-08-2020
Abstract: During the SARS epidemic in 2003/2004, a number of deletions were observed in ORF8 of SARS-CoV, and eventually deletion variants became predominant, leading to the hypothesis that ORF8 was an evolutionary hot spot for adaptation of SARS-CoV to humans. However, due to the successful control of the SARS epidemic, the importance of these deletions for the epidemiological fitness of SARS-CoV in humans could not be established. The emergence of multiple SARS-CoV-2 strains with ORF8 deletions, combined with evidence of a robust immune response to ORF8, suggests that the lack of ORF8 may assist with host immune evasion. In addition to providing a key insight into the evolutionary behavior of SARS-CoV-2 as the virus adapts to its new human hosts, the emergence of ORF8 deletion variants may also impact vaccination strategies.
Publisher: EMBO
Date: 21-01-2022
Abstract: The SARS-CoV-2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine-elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS-CoV-2 receptor-binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL-1β and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection.
Publisher: Springer Science and Business Media LLC
Date: 08-08-2022
DOI: 10.1038/S41467-022-32312-1
Abstract: Understanding the impact of age on vaccinations is essential for the design and delivery of vaccines against SARS-CoV-2. Here, we present findings from a comprehensive analysis of multiple compartments of the memory immune response in 312 in iduals vaccinated with the BNT162b2 SARS-CoV-2 mRNA vaccine. Two vaccine doses induce high antibody and T cell responses in most in iduals. However, antibody recognition of the Spike protein of the Delta and Omicron variants is less efficient than that of the ancestral Wuhan strain. Age-stratified analyses identify a group of low antibody responders where in iduals ≥60 years are overrepresented. Waning of the antibody and cellular responses is observed in 30% of the vaccinees after 6 months. However, age does not influence the waning of these responses. Taken together, while in iduals ≥60 years old take longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at 6 months post-vaccination. A third dose strongly boosts the low antibody responses in the older in iduals against the ancestral Wuhan strain, Delta and Omicron variants.
Location: France
No related grants have been discovered for Jean-Marc Chavatte.