Long-term prognosis at 1.5 years after infection with wild-type strain of SARS-CoV-2 and Alpha, Delta, as well as Omicron variants

The study, titled “Long-term prognosis at 1.5 years after infection with wild-type strain of SARS-CoV-2 and Alpha, Delta as well as Omicron variants,” focuses on the long-term prognosis of patients with long COVID.

Here are the detailed findings:

  1. Study Objectives and Methods: The study aimed to understand how different SARS-CoV-2 variants, including the Omicron variant, affect the prognosis of long COVID. The primary method involved a Post-COVID symptom Questionnaire (PCQ) and standard health scores, which were assessed at several points up to 1.5 years after infection.
  2. Participants and COVID-19 Variants: A total of 806 patients were enrolled, with cases including those infected with the wild-type strain, Alpha, Delta, and Omicron variants. Patients were grouped according to the dominant variant periods.
  3. Severity of Long COVID Symptoms: Patients infected in the Delta period exhibited more severe long COVID symptoms (mean PCQ of 43) compared to those infected in the wild-type period (mean PCQ of 38). Omicron-infected patients showed similar PCQ scores to wild-type patients but had more impaired functional levels and lower health-related quality of life.
  4. Trajectory of Long COVID: There was an initial significant reduction in median PCQ score from 7 to 10 months after infection. However, the severity of long COVID then plateaued, with no further decline observed until the end of the 18-month follow-up. This trend was consistent across all COVID-19 variants.
  5. Failure to Improve: Approximately 57% of the patients failed to show improvement above the minimal clinically important difference in PCQ. This lack of improvement was similar across all COVID-19 variants, indicating that more than half of the patients did not experience any improvement in long COVID severity 1.5 years after infection, regardless of the variant.
  6. Demographics and Severity Across Variants: The demographics of patients with long COVID did not vary significantly across the different SARS-CoV-2 variant periods. Interestingly, the severity of long COVID symptoms was similar when comparing Alpha, Delta, and Omicron periods to the wild-type period. More than 50% of patients did not improve during the follow-up period, irrespective of the variant.
  7. Study Limitations: The study acknowledges certain limitations, such as the potential influence of referral patterns to the Post-COVID Clinic, the variability in patients’ health literacy, and the evaluation of long COVID symptoms. Additionally, the study did not report vaccination status, although Denmark had high vaccine coverage before the Omicron period. It also did not register reinfections, which could have affected the severity of symptoms.

In conclusion, this study provides valuable insights into the long-term impacts of long COVID across different SARS-CoV-2 variants. It highlights the persistent nature of long COVID symptoms and the lack of significant improvement in many patients over time, regardless of the infecting COVID-19 variant.

Read More: https://www.ijidonline.com/article/S1201-9712(23)00760-9/fulltext#%20

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