"Abstract
Objectives: little is known about how the occurrence of long-term symptoms after Omicron infection compared with other variants is modulated by previous infections and/or vaccinations.
Methods: Participants of the DigiHero study provided information about their SARS-CoV-2 infections, vaccinations, and symptoms 12 or more weeks after infection (post-COVID-19 condition - PCC).
Introduction
Post-COVID-19 condition (PCC), commonly referred to as Long COVID, is defined as persisting symptoms 3 or more months after the initial SARS-CoV-2 infection that cannot be explained by an alternative diagnosis... There is a wide range of clinical symptoms associated with PCC, with more than 60 physical and mental sequelae. The symptoms reported most often were fatigue, shortness of breath, muscle, joint and chest pain, headache, cough, loss of taste and/or smell, and diarrhea...
Taking advantage of a large study in Germany, we compared the risk of developing PCC after infection with Wildtype, Alpha, Delta, and Omicron SARS-CoV-2, depending on previous vaccinations and/or infections. We also determined whether the time since previous vaccinations and/or infections plays a role. Furthermore, we evaluated the symptom severity and assessed the differences in the symptoms of PCC among the variants...
Results
Characteristics of the participants: Overall, 48,826 individuals completed the baseline questionnaire until June 15, 2022. We classified 286 (0.6%) participants as false positive, leaving 17,008 (34.8%) participants who had had at least one SARS-CoV-2 infection...
Risk of post-COVID-19 condition: ... Vaccination offered no meaningful protection against developing PCC in case of an infection. In contrast, there was a strong evidence that a previous infection reduced the risk of PCC...
Among those who developed PCC, symptom severity was similar for all variants and did not differ by vaccination status or if participants had had a previous infection...
Discussion
We found that participants infected with the Omicron variant had the lowest risk of developing PCC, followed by the Delta, Alpha, and Wildtype variants. The risk was substantially lower among those who had had previous infections, but it did not differ based on the vaccination status (among those who had been infected). In addition, the symptom severity in the case of developing PCC did not differ by the variant, the vaccination status, or previous infection...
More important is the observation that when distinguishing between the acute outcomes and PCC symptoms, a more recent study showed no protective effects of vaccination on the main PCC symptoms, which is also our finding."
© 2023 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).