Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial

Abstract:

Background: In the context of long COVID, persistent fatigue is among the most prevalent symptoms that can develop after SARS-CoV-2 infection. Mitochondrial myopathy and endothelial dysfunction, which are triggers of inflammation, have emerged as prominent causes of long COVID-induced fatigue. Interestingly, the intake of flavanols, particularly (−)-epicatechin (EC), has been associated with the positive modulation of endothelial and mitochondrial structure and function.
Methods: In this work, we conducted a randomized, double-blind, placebo-controlled clinical trial to determine whether an EC-enriched supplement (ECES) improves plasma markers of inflammation, endothelial structure, and fatigue-related endpoints in patients with long COVID-19.
Results: The study included 46 subjects (mean age 52 years) who were instructed to consume two capsules/day for 90 days of either ECES (n = 23) or placebo (n = 23). Endpoints assessed included mean changes in plasma inflammatory markers (IL-1β, IL-6, and TNF-α) and endothelial dysfunction markers (syndecan-1), handgrip strength, fatigue scale, and quality of life (QoL). The results showed significant improvements in the ECES group for inflammatory markers, syndecan-1, and fatigue compared with the placebo group.
Conclusions: The results yield intriguing positive findings for EC and open a new avenue for treating long COVID.
Source: Munguía L, Silva S, Villarreal F, Nájera N, Ceballos G. Effects of Cacao Flavonoids in Long COVID-19 Patients with Chronic Fatigue: FLALOC, a Placebo-Controlled Randomized Clinical Trial. Journal of Clinical Medicine. 2026; 15(4):1468. https://doi.org/10.3390/jcm15041468 https://www.mdpi.com/2077-0383/15/4/1468 (Full text)

Multimodal Web-Based Telerehabilitation for Patients With Post-COVID-19 Condition: Protocol for a Randomized Controlled Trial

Abstract:

Background: Patients with post-COVID-19 condition (PCC) experience persistent, long-term health consequences following SARS-CoV-2 infection, including fatigue, hyperventilation, cognitive impairment, and limitations in daily activities. There is emerging evidence suggesting that exercise and respiratory therapy-based telerehabilitation is safe and could potentially improve physical capacity while reducing health care costs.

Objective: This study aims to evaluate the superiority of a multimodal, symptom-titrated telerehabilitation program over standard care in patients with PCC who are severely affected, using the highest oxygen uptake rate (VO2peak [mL/min/kg]) achieved during the cardiopulmonary exercise test (CPET) and minute ventilation/carbon dioxide production slope (VE/VCO2 [full slope]) as primary outcomes. In addition, this study seeks to provide novel insights into the clinical and physiological adaptations associated with PCC, informing future rehabilitation strategies.

Methods: This prospective, randomized, waitlist-controlled trial was approved by the Rhineland-Palatinate Medical Association ethics committee. All procedures comply with the Declaration of Helsinki. This study comprises 3 examination time points, which include patient-reported outcomes, clinical assessments, and a CPET. It is structured into an 8-week intervention phase followed by an 8-week follow-up phase. Following baseline assessment, patients will be randomly assigned to either the intervention group (IG) or the control group (CG). During the intervention phase, IG participants will receive a web-based, multimodal, symptom-titrated telerehabilitation program consisting of sports medicine consultations, weekly teleconsultations, a structured pacing approach, and exercise and respiratory therapy. In contrast, CG participants will receive treatment as usual, which includes a single sports medicine consultation on healthy habits and a self-directed pacing approach for managing symptoms and daily activities. During the follow-up phase, IG participants will continue training independently without teleconsultations, whereas CG participants will undergo the same telerehabilitation intervention as the IG. A follow-up assessment will be conducted for both groups to evaluate long-term effects. This study adheres to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines and follows the Consensus on Exercise Reporting Template.

Results: Recruitment began in August 2023 and was extended until March 2025. As of March 2025, 80 participants have been recruited, and data analysis is ongoing. Final results are expected by December 2025, with a cross-sectional analysis of baseline data anticipated by July 2025.

Conclusions: This study is the first randomized controlled trial investigating the effectiveness of multimodal and symptom-titrated telerehabilitation in patients with PCC who are severely affected. The integration of various objective diagnostic systems will provide valuable insights into emerging postviral fatigue syndromes, supporting the development of CPET-based diagnostics, personalized rehabilitation strategies, and future research on long-term telerehabilitation effectiveness. The findings will be disseminated through peer-reviewed publications, professional networks, and patient advocacy groups to ensure scientific, clinical, and public impact.

Trial registration: German Clinical Trials Register (DRKS) DRKS00032394; https://drks.de/search/de/trial/DRKS00032394.

Source: Tomaskovic A, Weber V, Ochmann DT, Neuberger EW, Lachtermann E, Brahmer A, Haller N, Hillen B, Enders K, Eggert V, Zeier P, Lieb K, Simon P. Multimodal Web-Based Telerehabilitation for Patients With Post-COVID-19 Condition: Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2025 May 21;14:e65044. doi: 10.2196/65044. PMID: 40397936. https://www.researchprotocols.org/2025/1/e65044 (Full text)

Designing and optimizing clinical trials for long COVID

Abstract:

Long COVID is a debilitating, multisystemic illness following a SARS-CoV-2 infection whose duration may be indefinite. Over four years into the pandemic, little knowledge has been generated from clinical trials. We analyzed the information available on ClinicalTrials.gov, and found that the rigor and focus of trials vary widely, and that the majority test non-pharmacological interventions with insufficient evidence.

We highlight promising trials underway, and encourage the proliferation of clinical trials for treating Long COVID and other infection-associated chronic conditions and illnesses (IACCIs). We recommend several guidelines for Long COVID trials: First, pharmaceutical trials with potentially curative, primary interventions should be prioritized, and both drug repurposing and new drug development should be pursued.

Second, study designs should be both rigorous and accessible, e.g., triple-blinded randomized trials that can be conducted remotely, without participants needing to leave their homes.

Third, studies should have multiple illness comparator cohorts for IACCIs such as myalgic encephalomyelitis (ME/CFS) and dysautonomia, and screen for the full spectrum of symptomatology and pathologies of these illnesses.

Fourth, studies should consider inclusion/exclusion criteria with an eye towards equity and breadth of representation, including participants of all races, ethnicities, and genders most impacted by COVID-19, and including all levels of illness severity.

Fifth, involving patient-researchers in all aspects of studies brings immensely valuable perspectives that will increase the impact of trials. We also encourage the development of efficient clinical trial designs including methods to study several therapies in parallel.

Source: Vogel JM, Pollack B, Spier E, McCorkell L, Jaudon TW, Fitzgerald M, Davis H, Cohen AK. Designing and optimizing clinical trials for long COVID. Life Sci. 2024 Aug 13;355:122970. doi: 10.1016/j.lfs.2024.122970. Epub ahead of print. PMID: 39142505. https://www.sciencedirect.com/science/article/pii/S0024320524005605 (Full text)

Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19

Highlights:

  • A subset of patients experienced persistent fatigue symptoms after COVID-19.
  • Treatment with low-dose naltrexone (LDN) and NAD+ was well tolerated.
  • Treatment increased SF-36 quality of life scores.
  • Treatment also improved fatigue symptom scores.
  • A subset of patients were clinically responsive.

Abstract:

A subset of patients experiences persistent fatigue symptoms after COVID-19, and patients may develop long COVID, which is characterized by lasting systemic symptoms. No treatments for this condition have been validated and are urgently warranted.

In this pilot study, we assessed whether treatment with low-dose naltrexone (LDN, 4.5 mg/day) and supplementation with NAD + through iontophoresis patches could improve fatigue symptoms and quality of life in 36 patients with persistent moderate/severe fatigue after COVID-19.

We detected a significant increase from baseline in SF-36 survey scores after 12 weeks of treatment (mean total SF-36 score 36.5 [SD: 15.6] vs. 52.1 [24.8]; p < 0.0001), suggestive of improvement of quality of life. Furthermore, participants scored significantly lower on the Chalder fatigue scale after 12 weeks of treatment (baseline: 25.9 [4.6], 12 weeks: 17.4 [9.7]; p < 0.0001).

We found a subset of 52 % of patients to be responders after 12 weeks of treatment. Treatment was generally safe, with mild adverse events previously reported for LDN, which could be managed with dose adjustments. The iontophoresis patches were associated with mild, short-lived skin irritation in 25 % of patients.

Our data suggest treatment with LDN and NAD+ is safe and may be beneficial in a subset of patients with persistent fatigue after COVID-19. Larger randomized controlled trials will have to confirm our data and determine which patient subpopulations might benefit most from this strategy.

Source: Anar Isman, Andy Nyquist, Bailey Strecker, Girish Harinath, Virginia Lee, Xingyu Zhang, Sajad Zalzala. Low-dose naltrexone and NAD+ for the treatment of patients with persistent fatigue symptoms after COVID-19. Brain, Behavior, & Immunity – Health, Volume 36, 2024, 100733, ISSN 2666-3546, https://doi.org/10.1016/j.bbih.2024.100733. https://www.sciencedirect.com/science/article/pii/S2666354624000115 (Full text)

Herbal Medicines for Long COVID: A Phase 2 Pilot Clinical Study

Abstract:

Background: Infections of Coronavirus Disease-2019 (COVID-19) can cause long-term effects known as long COVID. This pilot study aimed to evaluate the feasibility of a clinical study as well as the efficacy and safety of traditional East Asian herbal medicines in alleviating fatigue and cognitive dysfunction “brain fog” in patients with long COVID.

Methods: This prospective pilot study investigated the use of three types of herbal medicines, Bojungikki-tang (BIT), Kyungok-go (KOG), and Cheonwangbosim-dan (CBD), for a 12-week period as potential treatments for fatigue and cognitive dysfunction in patients with long COVID. Forty-five patients with long COVID were recruited, and one of three drugs was given based on the patient’s symptoms and pattern identification. The effect of herbal medications on fatigue and cognitive function outcomes was assessed over a 36-week period, with patient adherence closely monitored.

Results: After 12 weeks of herbal drug administration, fatigue symptoms improved significantly across all groups, with treatment success rates of 80%, 53.33%, and 46.67% in the BIT, KOG, and CBD groups, respectively. However, “brain fog” symptoms showed less improvement, with treatment success rates of 40%, 46.67%, and 13.33% in the BIT, KOG, and CBD groups, respectively. All adverse events reported were mild and unrelated to the medication. The study design was found to be feasible with high medication adherence.

Conclusions: This study demonstrated the feasibility of conducting a clinical trial with three herbal medicines to treat long COVID symptoms like fatigue and “brain fog.”

Source:Kim, T.; Yoon, J.; Kim, S.; Kang, B.; Kang, J.W.; Kwon, S. Herbal Medicines for Long COVID: A Phase 2 Pilot Clinical Study. Preprints 2024, 2024011605. https://doi.org/10.20944/preprints202401.1605.v1 https://www.preprints.org/manuscript/202401.1605/v1 (Full text available as PDF file)

Creatine supplementation combined with breathing exercises reduces respiratory discomfort and improves creatine status in patients with long-COVID

Abstract:

Eight long-COVID patients with moderate fatigue that had lasted for ≥3 months were recruited. All patients were allocated in a double-blind parallel-group design to receive either 4 g of creatine per day plus breathing exercises (study group) or breathing exercises only (control group) for 3 months.

Creatine induced a significant increase in tissue total creatine levels for all 14 locations evaluated in the present study (P < 0.05), while its levels significantly dropped in the right frontal gray matter and left parietal mesial gray matter at follow-up in the control group (P < 0.05).

No change in time to exhaustion was demonstrated in the control group (P > 0.05), while the mean time to exhaustion was significantly improved for 54 s in the study group post-administration (P = 0.05).

These preliminary findings suggest that creatine is as an effective adjuvant therapeutic to breathing exercises for tackling the clinical features in long-COVID.

Source: Slankamenac, J; Ranisavljev, M; Todorovic, N; Ostojic, J; Stajer, V; Ostojic, SM. Creatine supplementation combined with breathing exercises reduces respiratory discomfort and improves creatine status in patients with long-COVID. Journal of Postgraduate Medicine ():, December 07, 2023. | DOI: 10.4103/jpgm.jpgm_650_23  https://journals.lww.com/jopm/abstract/9000/creatine_supplementation_combined_with_breathing.99983.aspx (Full text available as PDF file)

Experimental drugs in randomized controlled trials for long-COVID: what’s in the pipeline? A systematic and critical review

Article highlights:

  • Presently, no standard treatment exists for long-COVID, a post-coronavirus disease 2019 (COVID-19) syndrome, characterized by symptoms such as fatigue and brain fog lasting for 3 months or more after acute COVID-19.
  • Owing to increased funding, increasing numbers of randomized controlled trials (RCTs) on drug treatments for long-COVID are being conducted. We systematically and critically reviewed these RCTs to pinpoint drugs with high potential for treating long-COVID.
  • Of the four completed RCTs identified, three examined long-COVID prevention, of which only metformin was deemed to exhibit high potential in preventing long-COVID when administered during acute COVID-19. Only one RCT investigated the potential efficacy of a drug (Treamid) in treating ongoing long-COVID, showing low to modest potential due to its inefficacy in improving the more meaningful outcomes of long-COVID.
  • Of the 22 ongoing RCTs identified, only rintatolimod and LYT-100 (deupirfenidone) were judged as possessing modest to high potential for treating long-COVID.
  • The fact that nearly all of the drug candidates did not seem to exhibit high potential in treating long-COVID is a testament to the ordeal of treating long-COVID.
  • Given that long-COVID is a multifaceted condition with multiple proposed subtypes, its treatment may need to be tailored to specific subtypes.

Abstract:

Introduction: Over three years have passed since the emergence of coronavirus disease 2019 (COVID-19), and yet the treatment for long-COVID, a post-COVID-19 syndrome, remains long overdue. Currently, there is no standardized treatment available for long-COVID, primarily due to the lack of funding for post-acute infection syndromes (PAIS). Nevertheless, the past few years have seen a renewed interest in long-COVID research, with billions of dollars allocated for this purpose. As a result, multiple randomized controlled trials (RCTs) have been funded in the quest to find an effective treatment for long-COVID.

Areas covered: This systematic review identified and evaluated the potential of current drug treatments for long-COVID, examining both completed and ongoing RCTs.

Expert opinion: We identified four completed and 22 ongoing RCTs, investigating 22 unique drugs. However, most drugs were deemed to not have high potential for treating long-COVID, according to three pre-specified domains, a testament to the ordeal of treating long-COVID. Given that long-COVID is highly multifaceted with several proposed subtypes, treatments likely need to be tailored accordingly. Currently, rintatolimod appears to have modest to high potential for treating the myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) subtype, LTY-100 and Treamid for pulmonary fibrosis subtype, and metformin for general long-COVID prevention.

Source: Yong SJ, Halim A, Halim M, Ming LC, Goh KW, Alfaresi M, AlShehail BM, Al Fares MA, Alissa M, Sulaiman T, Alsalem Z, Alwashmi ASS, Khamis F, Al Kaabi NA, Albayat H, Alsheheri A, Garout M, Alsalman J, Alfaraj AH, Alhajri M, Dhama K, Alburaiky LM, Alsanad AH, AlShurbaji AT, Rabaan AA. Experimental drugs in randomized controlled trials for long-COVID: what’s in the pipeline? A systematic and critical review. Expert Opin Investig Drugs. 2023 Aug 4:1-13. doi: 10.1080/13543784.2023.2242773. Epub ahead of print. PMID: 37534972. https://pubmed.ncbi.nlm.nih.gov/37534972/

Where are the long COVID trials?

The news in early July, 2023, that STOP-PASC, a clinical trial at Stanford University, CA, USA, testing nirmatrelvir-ritonavir in patients with long COVID, is closing enrolment before the full study size has been reached, is disheartening. STOP-PASC is one of the few clinical trials studying a pharmacological intervention for long COVID and although the reason for termination hasn’t been confirmed yet, it adds to the dismal state of clinical research relative to the substantial burden of the condition.
ClinicalTrials.gov currently lists 386 trials under the search term Long COVID. However, only 94 of those studies are classed as interventional and are currently recruiting, and even more disturbing, only 12 trials are testing pharmacological interventions. The rest comprise follow-up of trials in acute infection, rehabilitation, food supplements, telehealth, psychological support, physiotherapy, acupuncture, light therapy, Chinese herbal medicine etc. While the list ranges from “nice to have additional support” to questionable alternative cures or even potentially harmful treatments, we are clearly lacking tested pharmacological interventions that treat the underlying pathophysiology.
There is a desperate need for long COVID treatments. Although estimates vary quite widely between populations and studies and depending on the definitions and methods used, 1 in 10 people experiences long COVID after infection. Lasting symptoms range from mild to disabling, with people unable to work or even bed-bound and unable to take care of basic personal needs. These individual tragedies have wide-ranging repercussions, leading to lost earnings, a shrinking workforce, and increased healthcare and social care costs. Again, estimates vary widely, but the impact is in the range of billions to trillions US dollars globally. Why do we only have 12 pharmacological interventional trials then?
Read the rest of this article HERE.
Source: Where are the long COVID trials? EDITORIAL, The Lancet Infectious Diseases, VOLUME 23, ISSUE 8, P879, AUGUST  Published:August, 2023. DOI: https://doi.org/10.1016/S1473-3099(23)00440-1 https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(23)00440-1/fulltext (Full text)

Autonomic Nervous System Affection Due to Post Covid Syndrome

Identification of the Effects of Post Covid Syndrome on the Autonomic Nervous System With Heart Rate Variability

Post-Covid syndrome is defined as symptoms that develop in addition to respiratory symptoms in individuals who have had Covid-19 infection for more than 12 weeks. Symptoms such as fatigue, headache, cognitive impairment, dyspnea, heart palpitations, heat intolerance, digestive system disorders, sleep disorders, dermal problems, orthostatic intolerance come to the fore in individuals with post-Covid syndrome. It has been tried to be revealed in some studies that Covid-19 infection affects the autonomic nervous system (ANS) and the relationship between Post-Covid 19 syndrome and ANS dysfunction.
Heart rate variability (HRV) measurement method can be used to evaluate ANS activity. HRV is a non-invasive method and is a measure of the change in heart rate over a period of time. HRV is a scalar quantity that shows the time between two beats of the heart and defines the oscillations between the R-R intervals. In HRV measurements, time-dependent and frequency-dependent measurement results are obtained and from these measurements, time-dependent RMSSD (square root of the square of the difference of the R-R intervals) and frequency-dependent high-frequency (HF) and low frequency (LF) measurement components are used in relation to the sympathetic nervous system (CNS) and parasympathetic nervous system (PSS). HRV can be measured in short-term (5 minutes) in terms of measurement time.
The aim of this study is to clearly reveal the relationship between Post-Covid 19 syndrome and ANS dysfunction and to provide standardization related to HRV measurement method and sub-parameters.
Source: Ali Veysel Özden, M.D. Bahçeşehir University. Istanbul, Beşiktaş, Turkey, 34000. ICH GCP US Clinical Trials Registry, Clinical Trial NCT05502094 https://ichgcp.net/clinical-trials-registry/NCT05502094

Co-production of a feasibility trial of pacing interventions for Long COVID

Abstract:

Background: The high incidence of COVID-19 globally has led to a large prevalence of Long COVID but there is a lack of evidence-based treatments. There is a need to evaluate existing treatments for symptoms associated with Long COVID. However, there is first a need to evaluate the feasibility of undertaking randomised controlled trials of interventions for the condition. We aimed to co-produce a feasibility study of non-pharmacological interventions to support people with Long COVID.

Methods: A consensus workshop on research prioritisation was conducted with patients and other stakeholders. This was followed by the co-production of the feasibility trial with a group of patient partners, which included the design of the study, the selection of interventions, and the production of dissemination strategies.

Results: The consensus workshop was attended by 23 stakeholders, including six patients. The consensus from the workshop was to develop a clinical trial platform that focused on testing different pacing interventions and resources. For the co-production of the feasibility trial, patient partners selected three pacing resources to evaluate (video, mobile application, and book) and co-designed feasibility study processes, study materials and undertook usability testing of the digital trial platform.

Conclusion: In conclusion, this paper reports the principles and process used to co-produce a feasibility study of pacing interventions for Long COVID. Co-production was effective and influenced important aspects of the study.

Source: Turner GM, McMullan C, Aiyegbusi OL, Hughes SE, Walker A, Jeyes F, Adler Y, Chong A, Buckland L, Stanton D, Davies EH, Haroon S, Calvert M. Co-production of a feasibility trial of pacing interventions for Long COVID. Res Involv Engagem. 2023 Mar 30;9(1):18. doi: 10.1186/s40900-023-00429-2. PMID: 36997975; PMCID: PMC10061378. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10061378/ (Full text)