A Comparative Study on the Pain Threshold Experienced by Fibromyalgia Patients Following Acute SARS-CoV-2 Infection

Significant gaps remain in the understanding of the etiology and pathogenesis of fibromyalgia (FM), and the COVID-19 pandemic has introduced even more unknowns. Social factors specific to that period, the viral infection itself, and/or vaccination are additional elements that can complicate the progression of the disease or the response to treatment. Aim: The primary hypothesis to be evaluated in this study is that an acute COVID-19 infection, even when considered recovered, may induce changes in the response to non-pharmacological treatment in FM patients, particularly concerning pain. Results: We included 128 patients diagnosed with FM before the pandemic began. The patients were divided based on their history of acute SARS-CoV-2 infection and COVID-19 vaccination status. All patients followed the same rehabilitation program (cognitive therapy, kinesitherapy). Perceived pain: The non-COVID-19 patient groups showed a statistically significant reduction in pain at the final evaluation compared to patients with a history of acute SARS-CoV-2 infection (p < 0.001). Algometric evaluation: Patients without COVID-19 infection and that were vaccinated exhibited the best improvement in pain threshold, both across evaluation times (p < 0.001) and compared to any of the other three groups studied (p < 0.001). Using the WHYMPI questionnaire, the same group of patients (those not having experienced acute COVID-19 and who were vaccinated) was the only group with a statistically significant improvement in pain severity (p = 0.009). In conclusion, to control and improve FM pain symptoms, in addition to appropriate medication, we propose paying additional attention to the history of acute SARS-CoV-2 infection and the COVID-19 vaccination status.