Amazon Foundation for Research Support/ (FAPESPA #006/2020 and #060/2020); Secretary of Science, Technology, and Higher, Professional and Technological Education (SECTET #09/2021); Brazilian Council of Scientific and Technological Development Agency (CNPq #401235/2020-3); and Conselho Nacional de Desenvolvimento Científico e Tecnológico—Brasil (INCT: 406360/2022-7).State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil / Federal University of Pará. Tropical Medicine Center. Belém, PA, Brazil / São Paulo University. School of Medicine. São Paulo, SP, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Virology. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil.Federal University of Pará. Institute of Health Sciences. Belém, PA, Brazil.Federal University of Pará. Institute of Health Sciences. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil / Federal University of Pará. Institute of Health Sciences. Belém, PA, Brazil / Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Genetic of Complex Discasse. Belém, PA, Brazil / Federal University of Pará.
Graduate Program in Biology of Infectious and Parasitic Agents. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil / Ministério da Saúde. Secretaria de Vigilância em Saúde e Ambiente. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Virology. Belém, PA, Brazil / Federal University of Pará. Graduate Program in Biology of Infectious and Parasitic Agents. Belém, PA, Brazil.State University of Pará. Center for Biological Health Sciences. Belém, PA, Brazil / São Paulo University. School of Medicine. São Paulo, SP, Brazil.A persistent state of inflammation has been reported during the COVID-19 pandemic. This study aimed to assess short-term heart rate variability (HRV), peripheral body temperature, and serum cytokine levels in patients with long COVID. We evaluated 202 patients with long COVID symptoms categorized them according to the duration of their COVID symptoms (≤120 days, n = 81; >120 days, n = 121), in addition to 95 healthy individuals selected as controls. All HRV variables differed significantly between the control group and patients with long COVID in the ≤120 days group (p 120 days group in all regions analysed (p < 0.05). Cytokine analysis showed higher levels of interleukin 17 (IL-17) and interleukin 2 (IL-2), and lower levels of interleukin 4 (IL-4) (p < 0.05). Our results suggest a reduction in parasympathetic activation during long COVID and an increase in body temperature due to possible endothelial damage caused by the maintenance of elevated levels of inflammatory mediators. Furthermore, high serum levels of IL-17 and IL-2 and low levels of IL-4 appear to constitute a long-term profile of COVID-19 cytokines, and these markers are potential targets for long COVID-treatment and prevention strategies
