- Published
- 13 December 2023
- Journal article
Effect of second booster vaccinations and prior infection against SARS-CoV-2 in the UK SIREN healthcare worker cohort
- Authors
-
- Source
- The Lancet Regional Health - Europe
Abstract
Background
The protection of fourth dose mRNA vaccination against SARS-CoV-2 is relevant to current global policy decisions regarding ongoing booster roll-out. We aimed to estimate the effect of fourth dose vaccination, prior infection, and duration of PCR positivity in a highly-vaccinated and largely prior-COVID-19 infected cohort of UK healthcare workers.
Methods
Participants underwent fortnightly PCR and regular antibody testing for SARS-CoV-2 and completed symptoms questionnaires. A multi-state model was used to estimate vaccine effectiveness (VE) against infection from a fourth dose compared to a waned third dose, with protection from prior infection and duration of PCR positivity jointly estimated.
Findings
1298 infections were detected among 9560 individuals under active follow-up between September 2022 and March 2023. Compared to a waned third dose, fourth dose VE was 13.1% (95% CI 0.9 to 23.8) overall; 24.0% (95% CI 8.5 to 36.8) in the first 2 months post-vaccination, reducing to 10.3% (95% CI −11.4 to 27.8) and 1.7% (95% CI −17.0 to 17.4) at 2–4 and 4–6 months, respectively. Relative to an infection >2 years ago and controlling for vaccination, 63.6% (95% CI 46.9 to 75.0) and 29.1% (95% CI 3.8 to 43.1) greater protection against infection was estimated for an infection within the past 0–6, and 6–12 months, respectively. A fourth dose was associated with greater protection against asymptomatic infection than symptomatic infection, whilst prior infection independently provided more protection against symptomatic infection, particularly if the infection had occurred within the previous 6 months. Duration of PCR positivity was significantly lower for asymptomatic compared to symptomatic infection.
Interpretation
Despite rapid waning of protection, vaccine boosters remain an important tool in responding to the dynamic COVID-19 landscape; boosting population immunity in advance of periods of anticipated pressure, such as surging infection rates or emerging variants of concern.
Cite as
Kirwan, P., Hall, V., Foulkes, S., Otter, A., Munro, K., Sparkes, D., Howells, A., Platt, N., Broad, J., Crossman, D., Norman, C., Corrigan, D., Jackson, C., Cole, M., Brown, C., Atti, A., Islam, J., Dembinsky, M., Goldberg, D., Haahr, L., Jorgenson, A., Matuluko, A., Nuryunarsih, D., Price, L., Sergenson, N., Stewart, S., Presanis, A., Charlett, A., De Angelis, D., Hopkins, S. & SIREN Study Group 2023, 'Effect of second booster vaccinations and prior infection against SARS-CoV-2 in the UK SIREN healthcare worker cohort', The Lancet Regional Health - Europe, 36, article no: 100809. https://doi.org/10.1016/j.lanepe.2023.100809