A Chronological History of the COVID-19 Pandemic
This article is Coronavirus Timeline Part 3. To visit Coronavirus Timeline Part 2 click here.
- June 2, 2021: Prior SARS-CoV-2 infection rescues B and T cell responses to variants after first vaccine dose. A boost from infection. During clinical trials of severe acute respiratory syndrome coronavirus 2 vaccines, no one who had survived infection with the virus was tested. A year after the pandemic was declared, vaccination of previously infected persons is a reality. Reynolds et al. address the knowledge gap in a cohort of UK health care workers given the Pfizer/BioNTech vaccine in which half of the participants had experienced natural virus infections early in the pandemic (see the Perspective by Crotty). Genotyping indicated that a genetic component underlies heterogeneity in immune responses to vaccine and to natural infection. After vaccination, naïve individuals developed antibody responses similar to those seen in naturally infected persons, but T cell responses were more limited and sometimes absent. However, antibody and memory responses in individuals vaccinated after infection were substantially boosted to the extent that a single vaccine dose is likely to protect against the more aggressive B.1.1.7 variant. It is possible that the messenger RNA vaccine has an adjuvant effect, biasing responses toward antibody generation.
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