“Two-Dose COVID-19 mRNA Vaccination Conferred Limited Adaptive Immune Response Among the Aged Mice Which Rendered Them Susceptible to SARS-CoV-2 Infection” By Brian Simpson
A very recently published study in the journal, Emerging Microbes and Infection, undertook a mouse model of Covid infection to investigate age-associated breakthrough Covid infections, that is, Covid infections in vaccinated mice. It was found that he immune systems of the aged mice were significantly impaired compared to that of younger mice, and the aged mice were more susceptible to re-infection, also due to decreased immune function. It is hypothesised that the same result may be replicated in human populations.
“Emerg Microbes Infect
2022 Jan 6;1-36.
doi: 10.1080/22221751.2022.2026741. Online ahead of print.
Age-associated SARS-CoV-2 breakthrough infection and changes in immune response in mouse model
Yanxia Chen 1 2, Can Li 1 3 2, Feifei Liu 1, Zhanhong Ye 1, Wenchen Song 1 3, Andrew C Y Lee 1 3, Huiping Shuai 1, Lu Lu 1, Kelvin Kai-Wang To 1 4 3 5, Jasper Fuk-Woo Chan 1 4 3 5 6, Anna Jinxia Zhang 1 3, Hin Chu 1 3 5, Kwok-Yung Yuen 1 4 3 5 6
Affiliations expand
- PMID: 34989330
Abstract
ABSTRACT Older individuals are at higher risk of SARS-CoV-2 infection and severe outcome but the underlying mechanisms are incompletely understood. In addition, how age modulates SARS-CoV-2 re-infection and vaccine breakthrough infections remains largely unexplored. Here, we investigated age-associated SARS-CoV-2 pathogenesis, immune responses, and the occurrence of re-infection and vaccine breakthrough infection utilizing a wild type C57BL/6N mouse model. We demonstrated that interferon and adaptive antibody response upon SARS-CoV-2 challenge are significantly impaired in aged mice in comparison to young mice, which results in more effective virus replication and severe disease manifestations in the respiratory tract. Aged mice also showed increased susceptibility to re-infection due to insufficient immune protection acquired during primary infection. Importantly, two-dose COVID-19 mRNA vaccination conferred limited adaptive immune response among the aged mice which rendered them susceptible to SARS-CoV-2 infection. Collectively, our findings call for tailored and optimized treatment and prevention strategies against SARS-CoV-2 among the older individuals.
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