Is the immune neuroendocrine system the connection between epipharyngitis and chronic fatigue syndrome induced by HPV vaccine? : Editorial

Transitional Changes in Fatigue-Related Symptoms Due to Long COVID: A Single-Center Retrospective Observational Study in Japan

Background and Objectives: Changes in post COVID-19 condition (PCC) characteristics caused by viral variants have yet to be clarified. We aimed to characterize the differences between clinical backgrounds and manifestations in long COVID patients who were infected with the Delta variant and those who were infected with the Omicron variants. Materials and Methods: This study was a single-center retrospective observational study for patients who visited our COVID-19 aftercare outpatient clinic (CAC) established in Okayama University Hospital (Japan) during the period from 15 February 2021 to 15 July 2022. We classified the onset of COVID-19 in the patients into three groups, the preceding, Delta-dominant, and Omicron-dominant periods, based on the prevalent periods of the variants in our prefecture. Results: In a total of 353 patients, after excluding 8 patients, 110, 130, and 113 patients were classified into the preceding, Delta-dominant, and Omicron-dominant periods, respectively. Patients infected in the Omicron-dominant period had significantly fewer hospitalizations, milder illnesses, more vaccinations and earlier visit to the CAC than did patients infected in the Delta-dominant period. Patients infected in the Omicron-dominant period had significantly lower frequencies of dysosmia (12% vs. 45%, ** p < 0.01), dysgeusia (14% vs. 40%, ** p < 0.01) and hair loss (7% vs. 28%, ** p < 0.01) but had higher frequencies of fatigue (65% vs. 50%, * p < 0.05), insomnia (26% vs. 13%, * p < 0.05) and cough (20% vs. 7%, ** p < 0.01) than did patients infected in the Delta-dominant period. Conclusions: The transitional changes in long COVID symptoms caused by the two variants were characterized.

The immune-neuroendocrine system in COVID-19, advanced age and rheumatic diseases

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The immune-neuroendocrine system is essential to maintain homeostasis specially during stress situations. COVID-19 infection, produce stress, and activates the immune–neuroendocrine system. During the COVID-19 pandemic, multiple studies indicate that the most vulnerable populations are older adults and patients with comorbidities including autoimmune rheumatic diseases. These patients suffer from extremely important situation that favors the inflammatory hyper response due to an inadequate reaction of the immune-neuroendocrine system. This review aims to analyze the findings of the effect of COVID-19 on the hypothalamic–pituitary–adrenal, hypothalamic–pituitary–gonadal, hypothalamic–pituitary–thyroid, hypothalamic–pituitary–prolactin axes, and central nervous system, as well as the response to this viral infection in older adults and patients with rheumatic diseases and perspectives about this subject.