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The impact of vaccination and SARS-CoV-2 variants on the virological response to SARS-CoV-2 infections during the Alpha, Delta, and Omicron waves in England.

The impact of vaccination and SARS-CoV-2 variants on the virological response to SARS-CoV-2 infections during the Alpha, Delta, and Omicron waves in England.

Authors :
Lunt, Rachel
Quinot, Catherine
Kirsebom, Freja
Andrews, Nick
Skarnes, Catriona
Letley, Louise
Haskins, Donna
Angel, Catriona
Firminger, Skye
Ratcliffe, Kay
Rajan, Shelina
Sherridan, Angela
Ijaz, Samreen
Zambon, Maria
Brown, Kevin
Ramsay, Mary
Bernal, Jamie Lopez
Source :
Journal of Infection; Jan2024, Vol. 88 Issue 1, p21-29, 9p
Publication Year :
2024

Abstract

Vaccination status and the SARS-CoV-2 variant individuals are infected with are known to independently impact viral dynamics; however, little is known about the interaction of these two factors and how this impacts viral dynamics. Here we investigated how monovalent vaccination modified the time course and viral load of infections from different variants. Regression analyses were used to investigate the impact of vaccination on cycle threshold values and disease severity, and interval-censored survival analyses were used to investigate the impact of vaccination on duration of positivity. A range of covariates were adjusted for as potential confounders and investigated for their own effects in exploratory analyses. All analyses were done combining all variants and stratified by variant. For those infected with Alpha or Delta, vaccinated individuals were more likely to report mild disease than moderate/severe disease and had significantly shorter duration of positivity and lower viral loads compared to unvaccinated individuals. Vaccination had no impact on self-reported disease severity, viral load, or duration if positivity for those infected with Omicron. Overall, individuals who were immunosuppressed and clinically extremely vulnerable had longer duration of positivity and higher viral loads. This study adds to the evidence base on disease dynamics following COVID-19, demonstrating that vaccination mitigates severity of disease, the amount of detectable virus within infected individuals and reduces the time individuals are positive for. However, these effects have been significantly attenuated since the emergence of Omicron. Therefore, our findings strengthen the argument for using modified or multivalent vaccines that target emerging variants. • Vaccinated individuals had a shorter duration of positivity, lower viral load and less severe disease. • Effect of vaccination is less obvious for Omicron infections suggesting that vaccines may be less effective against Omicron subvariants. • Vaccinated individuals have significantly lower odds of developing moderate/severe disease. • Immunosuppressed or clinically extremely vulnerable individuals had longer durations of positivity and higher viral load. • Degree of protection offered by vaccine-induced immune responses varied depending on the variant to which an individual was exposed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01634453
Volume :
88
Issue :
1
Database :
Supplemental Index
Journal :
Journal of Infection
Publication Type :
Academic Journal
Accession number :
174604769
Full Text :
https://doi.org/10.1016/j.jinf.2023.10.016