Viruses (Sep 2024)

The Omicron Variant Is Associated with a Reduced Risk of the Post COVID-19 Condition and Its Main Phenotypes Compared to the Wild-Type Virus: Results from the EuCARE-POSTCOVID-19 Study

  • Francesca Bai,
  • Andrea Santoro,
  • Pontus Hedberg,
  • Alessandro Tavelli,
  • Sara De Benedittis,
  • Júlia Fonseca de Morais Caporali,
  • Carolina Coimbra Marinho,
  • Arnaldo Santos Leite,
  • Maria Mercedes Santoro,
  • Francesca Ceccherini Silberstein,
  • Marco Iannetta,
  • Dovilé Juozapaité,
  • Edita Strumiliene,
  • André Almeida,
  • Cristina Toscano,
  • Jesús Arturo Ruiz-Quiñones,
  • Chiara Mommo,
  • Iuri Fanti,
  • Francesca Incardona,
  • Alessandro Cozzi-Lepri,
  • Giulia Marchetti

DOI
https://doi.org/10.3390/v16091500
Journal volume & issue
Vol. 16, no. 9
p. 1500

Abstract

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Post COVID-19 condition (PCC) is defined as ongoing symptoms at ≥1 month after acute COVID-19. We investigated the risk of PCC in an international cohort according to viral variants. We included 7699 hospitalized patients in six centers (January 2020–June 2023); a subset of participants with ≥1 visit over the year after clinical recovery were analyzed. Variants were observed or estimated using Global Data Science Initiative (GISAID) data. Because patients returning for a post COVID-19 visit may have a higher PCC risk, and because the variant could be associated with the probability of returning, we used weighted logistic regressions. We estimated the proportion of the effect of wild-type (WT) virus vs. Omicron on PCC, which was mediated by Intensive Care Unit (ICU) admission, through a mediation analysis. In total, 1317 patients returned for a post COVID visit at a median of 2.6 (IQR 1.84–3.97) months after clinical recovery. WT was present in 69.6% of participants, followed by the Alpha (14.4%), Delta (8.9%), Gamma (3.9%) and Omicron strains (3.3%). Among patients with PCC, the most common manifestations were fatigue (51.7%), brain fog (32.7%) and respiratory symptoms (37.2%). Omicron vs. WT was associated with a reduced risk of PCC and PCC clusters; conversely, we observed a higher risk with the Delta and Alpha variants vs. WT. In total, 42% of the WT effect vs. Omicron on PCC risk appeared to be mediated by ICU admission. A reduced PCC risk was observed after Omicron infection, suggesting a possible reduction in the PCC burden over time. A non-negligible proportion of the variant effect on PCC risk seems mediated by increased disease severity during the acute disease.

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