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Previous SARS-CoV-2 infections and their impact on the protection from reinfection during the Omicron BA.5 wave – a nested case-control study among vaccinated adults in Sweden

Kahn, Fredrik LU ; Bonander, Carl ; Moghaddassi, Mahnaz LU ; Christiansen, Claus Bohn ; Bennet, Louise LU orcid ; Malmqvist, Ulf ; Inghammar, Malin LU and Björk, Jonas LU (2024) In IJID Regions 10. p.235-239
Abstract

Objectives: We evaluated the protection afforded by SARS-CoV-2 infection-induced immunity against reinfection among working-age vaccinated individuals during a calendar period from June to December 2022 when Omicron BA.5 was the dominating subvariant in Scania County, Sweden. Methods: The study cohort (n = 71,592) mainly consisted of health care workers. We analyzed 4144 infected cases during the Omicron BA.5 dominance and 41,440 sex- and age-matched controls with conditional logistic regression. Results: The average protection against reinfection was marginal (16%, 95% confidence interval [CI] 7-23%) during the study period but substantially higher for recent infections. Recent infection (3-6 months) with Omicron BA.2 and BA.5 offered... (More)

Objectives: We evaluated the protection afforded by SARS-CoV-2 infection-induced immunity against reinfection among working-age vaccinated individuals during a calendar period from June to December 2022 when Omicron BA.5 was the dominating subvariant in Scania County, Sweden. Methods: The study cohort (n = 71,592) mainly consisted of health care workers. We analyzed 4144 infected cases during the Omicron BA.5 dominance and 41,440 sex- and age-matched controls with conditional logistic regression. Results: The average protection against reinfection was marginal (16%, 95% confidence interval [CI] 7-23%) during the study period but substantially higher for recent infections. Recent infection (3-6 months) with Omicron BA.2 and BA.5 offered strong protection (86%, 95% CI 68-94% and 78%, 95% CI 69-84%), whereas more distant infection (6-12 months) with Omicron BA.1, BA.2, and the variants before Omicron offered marginal or no protection. Conclusions: These findings suggest that infection-induced immunity contributes to short-term population protection against infection with the subvariant BA.5 among working-age vaccinated individuals but wanes considerably with time, independent of the virus variant.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Epidemiological surveillance, SARS-CoV-2 infection, Variant of concern
in
IJID Regions
volume
10
pages
5 pages
publisher
Elsevier
external identifiers
  • pmid:38532742
  • scopus:85187403707
ISSN
2772-7076
DOI
10.1016/j.ijregi.2024.02.004
project
Improved preparedness for future pandemics and other health crises through large-scale disease surveillance
language
English
LU publication?
yes
id
385e7a63-9aed-4b3d-b38b-a068f6769609
date added to LUP
2024-04-09 12:02:03
date last changed
2024-04-23 14:52:42
@article{385e7a63-9aed-4b3d-b38b-a068f6769609,
  abstract     = {{<p>Objectives: We evaluated the protection afforded by SARS-CoV-2 infection-induced immunity against reinfection among working-age vaccinated individuals during a calendar period from June to December 2022 when Omicron BA.5 was the dominating subvariant in Scania County, Sweden. Methods: The study cohort (n = 71,592) mainly consisted of health care workers. We analyzed 4144 infected cases during the Omicron BA.5 dominance and 41,440 sex- and age-matched controls with conditional logistic regression. Results: The average protection against reinfection was marginal (16%, 95% confidence interval [CI] 7-23%) during the study period but substantially higher for recent infections. Recent infection (3-6 months) with Omicron BA.2 and BA.5 offered strong protection (86%, 95% CI 68-94% and 78%, 95% CI 69-84%), whereas more distant infection (6-12 months) with Omicron BA.1, BA.2, and the variants before Omicron offered marginal or no protection. Conclusions: These findings suggest that infection-induced immunity contributes to short-term population protection against infection with the subvariant BA.5 among working-age vaccinated individuals but wanes considerably with time, independent of the virus variant.</p>}},
  author       = {{Kahn, Fredrik and Bonander, Carl and Moghaddassi, Mahnaz and Christiansen, Claus Bohn and Bennet, Louise and Malmqvist, Ulf and Inghammar, Malin and Björk, Jonas}},
  issn         = {{2772-7076}},
  keywords     = {{Epidemiological surveillance; SARS-CoV-2 infection; Variant of concern}},
  language     = {{eng}},
  pages        = {{235--239}},
  publisher    = {{Elsevier}},
  series       = {{IJID Regions}},
  title        = {{Previous SARS-CoV-2 infections and their impact on the protection from reinfection during the Omicron BA.5 wave – a nested case-control study among vaccinated adults in Sweden}},
  url          = {{http://dx.doi.org/10.1016/j.ijregi.2024.02.004}},
  doi          = {{10.1016/j.ijregi.2024.02.004}},
  volume       = {{10}},
  year         = {{2024}},
}