Long COVID: Clinical Findings, Pathology, and Endothelial Molecular Mechanisms

SARS-CoV-2 evolution has increased resistance to monoclonal antibodies and first-generation COVID-19 vaccines: Is there a future therapeutic role for soluble ACE2 receptors for COVID-19?

COVID-19 has caused calamitous health, economic and societal consequences. Although several COVID-19 vaccines have received full authorization for use, global deployment has faced political, financial and logistical challenges. The efficacy of first-generation COVID-19 vaccines is waning and breakthrough infections are allowing ongoing transmission and evolution of SARS-CoV-2. Furthermore, COVID-19 vaccine efficacy relies on a functional immune system. Despite receiving three primary doses and three or more heterologous boosters, some immunocompromised patients may not be adequately protected by COVID-19 vaccines and remain vulnerable to severe disease. The evolution of new SARS-CoV-2 variants has also resulted in the rapid obsolescence of monoclonal antibodies. Convalescent plasma from COVID-19 survivors has produced inconsistent results. New drugs such as Paxlovid (nirmatrelvir/ritonavir) are beyond the reach of low- and middle-income countries. With widespread use of Paxlovid, it is likely nirmatrelvir-resistant clades of SARS-CoV-2 will emerge in the future. There is thus an urgent need for new effective anti-SARS-CoV-2 treatments. The in vitro efficacy of soluble ACE2 against multiple SARS-CoV-2 variants including omicron (B.1.1.529), was recently described using a competitive ELISA assay as a surrogate marker for virus neutralization. This indicates soluble wild-type ACE2 receptors are likely to be resistant to viral evolution. Nasal and inhaled treatment with soluble ACE2 receptors has abrogated severe disease in animal models of COVID-19. There is an urgent need for clinical trials of this new class of antiviral therapeutics, which could complement vaccines and Paxlovid.

Diaphragmatic strengthening exercises for patients with post COVID-19 condition after mild-to-moderate acute COVID-19 infection: a randomized controlled study

OBJECTIVE

To assess the clinical effects of incentive spirometry (IS) and diaphragmatic breathing (DB) in patients with post COVID-19 condition and diaphragmatic dysfunction as compared with the standard care alone.

METHODS

The present longitudinal randomized study included 60 patients with post COVID-19 condition and diaphragmatic dysfunction. Patients were equally randomized to receive standard care plus IS (G1), standard care plus DB (G2) or standard care alone (G3) for 8 weeks. The primary outcome is clinical improvement as evaluated by the modified Medical Research Council (mMRC) dyspnoea scale.

RESULTS

Comparison between the studied groups revealed significant improvement in G1 and G2 in all parameters at the end of follow-up. However, no significant improvement was found in G3. At the end of follow-up, 15 patients (75.0%) in G1, 11 patients (55.0%) in G2, and 3 patients (15.0%) in G3 showed improvement on the mMRC dyspnoea scale. Multivariate logistic regression analysis identified mild acute COVID-19 infection (p = 0.009), use of IS (p < 0.001), and use of DB (p = 0.023) as significant predictors of improvement on the mMRC dyspnoea scale.

CONCLUSIONS

IS or DB training in addition to the standard care in post COVID-19 condition was associated with better clinical improvement as compared with the standard care alone.

Long COVID or Post-COVID-19 Condition: Past, Present and Future Research Directions

The presence of symptoms after an acute SARS-CoV-2 infection (long-COVID) has become a worldwide healthcare emergency but remains underestimated and undertreated due to a lack of recognition of the condition and knowledge of the underlying mechanisms. In fact, the prevalence of post-COVID symptoms ranges from 50% during the first months after the infection up to 20% two-years after. This perspective review aimed to map the existing literature on post-COVID symptoms and to identify gaps in the literature to guide the global effort toward an improved understanding of long-COVID and suggest future research directions. There is a plethora of symptomatology that can be due to COVID-19; however, today, there is no clear classification and definition of this condition, termed long-COVID or post-COVID-19 condition. The heterogeneity in the symptomatology has led to the presence of groups/clusters of patients, which could exhibit different risk factors and different mechanisms. Viral persistence, long-lasting inflammation, immune dysregulation, autoimmune reactions, reactivation of latent infections, endothelial dysfunction and alteration in gut microbiota have been proposed as potential mechanisms explaining the complexity of long-COVID. In such an equation, viral biology (e.g., re-infections, SARS-CoV-2 variants), host biology (e.g., genetics, epigenetics) and external factors (e.g., vaccination) should be also considered. These various factors will be discussed in the current perspective review and future directions suggested.