Malika Seydou Beidari
Self-reported symptoms of Post COVID-19 Condition after a SARS-CoV-2 vaccine dose: study of the factors associated with symptoms deterioration
As of November 2023, over 772 million people have been infected with COVID-19 worldwide. It is estimated that over 200 million people have been affected by the long-term effects of COVID-19. According to current data, 10-20% of infected people will continue to experience debilitating symptoms 12 weeks after initial infection, which could affect up to 2.6 million Canadians. During the first 18 months of the pandemic, this phenomenon was called the “long COVID” or “post-acute sequelae of COVID-19 (PASC)”. In October 2021, the World Health Organization (WHO) determined the official name of this syndrome to be “Post-COVID-19 Condition” (PCC) and developed a clinical case definition: “Post-COVID-19 Condition occurs in people with a history of probable or confirmed SARS-CoV-2 infection, usually 3 months after initial infection with COVID-19 with symptoms that persist for at least 2 months and cannot be explained by another diagnosis“.
PCC constitutes a wide range of new, recurrent, or persistent symptoms that people experience after being infected with the SARS-CoV-2 virus. Since this phenomenon was recognized, many research efforts have been deployed to understand the pathophysiology of the syndrome. Depending on the systems affected, the proposed development mechanisms are different (6). Many people with PCC have systemic inflammation, immune dysregulation, and elevated inflammatory biomarkers after the initial infection. While there are biological factors of PCC according to some studies, other hypotheses focus on psychological or social causes.
From the beginning of the vaccination campaign, hypotheses emerged suggesting that the vaccines could have an impact on the evolution of PCC symptoms. Vaccines have unequivocally demonstrated efficacy in reducing disease incidence, virus transmission, hospitalizations and deaths from COVID-19. There is also strong evidence to support that vaccination prevents the development of PCC. However, there is a lack of evidence about the impact of post-infection vaccination on PCC symptoms. The existing literature is inconsistent on this question. Existing systematic reviews suggest variable impacts, such as improvement, deterioration, or status quo on persistent COVID-19 symptoms. Many of these authors call for additional research to explore the impact of vaccination on PCC symptoms in patients who have PCC. In CCEDRRN data published in Nature communications, we observed that a higher proportion of patients with persistent PCC symptoms reported a deterioration of their symptoms after a vaccine dose. For this reason, it is important to investigate this result to develop a better understanding of the relationship between post-infection SARS-CoV-2 vaccination and the deterioration of PCC symptoms.
The primary objective of this study is to identify the risk factors that are related to the deterioration vs. non-deterioration of PCC symptoms after a dose of vaccination against SARS-CoV-2. This will allow us to understand the profile of patients (e.g., age, sex, comorbidities, symptom profile) associated with a deterioration of their PCC symptoms post vaccination.