Abstract
Background: Both infection and vaccination, alone or in combination, generate antibody and T cell responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the maintenance of such responses—and hence protection from disease—requires careful characterization. In a large prospective study of UK healthcare workers (HCWs) (Protective Immunity from T Cells in Healthcare Workers [PITCH], within the larger SARS-CoV-2 Immunity and Reinfection Evaluation [SIREN] study), we previously observed that prior infection strongly affected subsequent cellular and humoral immunity induced after long and short dosing intervals of BNT162b2 (Pfizer/BioNTech) vaccination.
Methods: Here, we report longer follow-up of 684 HCWs in this cohort over 6–9 months following two doses of BNT162b2 or AZD1222 (Oxford/AstraZeneca) vaccination and up to 6 months following a subsequent mRNA booster vaccination.
Findings: We make three observations: first, the dynamics of humoral and cellular responses differ; binding and neutralizing antibodies declined, whereas T and memory B cell responses were maintained after the second vaccine dose. Second, vaccine boosting restored immunoglobulin (Ig) G levels; broadened neutralizing activity against variants of concern, including Omicron BA.1, BA.2, and BA.5; and boosted T cell responses above the 6-month level after dose 2. Third, prior infection maintained its impact driving larger and broader T cell responses compared with never-infected people, a feature maintained until 6 months after the third dose.
Conclusions: Broadly cross-reactive T cell responses are well maintained over time—especially in those with combined vaccine and infection-induced immunity (“hybrid” immunity)—and may contribute to continued protection against severe disease.
Funding: Department for Health and Social Care, Medical Research Council.
Methods: Here, we report longer follow-up of 684 HCWs in this cohort over 6–9 months following two doses of BNT162b2 or AZD1222 (Oxford/AstraZeneca) vaccination and up to 6 months following a subsequent mRNA booster vaccination.
Findings: We make three observations: first, the dynamics of humoral and cellular responses differ; binding and neutralizing antibodies declined, whereas T and memory B cell responses were maintained after the second vaccine dose. Second, vaccine boosting restored immunoglobulin (Ig) G levels; broadened neutralizing activity against variants of concern, including Omicron BA.1, BA.2, and BA.5; and boosted T cell responses above the 6-month level after dose 2. Third, prior infection maintained its impact driving larger and broader T cell responses compared with never-infected people, a feature maintained until 6 months after the third dose.
Conclusions: Broadly cross-reactive T cell responses are well maintained over time—especially in those with combined vaccine and infection-induced immunity (“hybrid” immunity)—and may contribute to continued protection against severe disease.
Funding: Department for Health and Social Care, Medical Research Council.
| Original language | English |
|---|---|
| Pages (from-to) | 191-215.e9 |
| Number of pages | 35 |
| Journal | Med |
| Volume | 4 |
| Issue number | 3 |
| Early online date | 16 Feb 2023 |
| DOIs | |
| Publication status | Published - 10 Mar 2023 |
UN SDGs
This output contributes to the following UN Sustainable Development Goals (SDGs)
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SDG 3 Good Health and Well-being
Keywords
- SARS-CoV-2
- COVID-19
- COVID vaccine
- T cells
- antibody
- immunity
Fingerprint
Dive into the research topics of 'Evolution of long-term vaccine-induced and hybrid immunity in healthcare workers after different COVID-19 vaccine regimens'. Together they form a unique fingerprint.Projects
- 1 Finished
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Investigation of proven vaccine breakthrough by SARS-CoV-2 variants in established UK healthcare worker cohorts: SIREN consortium & PITCH Plus Pathway
Richter, A. (Principal Investigator)
13/08/21 → 10/02/23
Project: Research Councils
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