COVID-19 Mechanisms in the Human Body—What We Know So Far

Parashar

Journal of Medical Virology

et al. 2021

Self Cite

Young age, female sex, absence of comorbidities, and prior infection or vaccination are known epidemiological barriers for contracting the new infection and/or increased disease severity. Demographic trends from the recent coronavirus disease 2019 waves, which are believed to be driven by newer severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, indicate that the aforementioned epidemiological barriers are being breached and a larger number of younger and healthy individuals are developing severe disease. The new SARS-CoV-2 variants have key mutations that can induce significant changes in the virus-host interactions. Recent studies report that, some of these mutations, singly or in a group, enhance key mechanisms, such as binding of the receptor-binding domain (RBD) of the viral spike protein with the angiotensin-converting enzyme 2 (ACE2) receptor in the hostcells, increase the glycosylation of spike protein at the antigenic sites, and enhance the proteolytic cleavage of the spike protein, thus leading to improved host-cell entry and the replication of the virus. The putative changes in the virus-host interactions imparted by the mutations in the RBD sequence can potentially be the reason behind the breach of the observed epidemiological barriers. Susceptibility for contracting SARS-CoV-2 infection and the disease outcomes are known to be influenced by host-cell expressions of ACE2 and other proteases. The new variants can act more efficiently, and even with the lesser availability of the viral entryreceptor and the associated proteases, can have more efficient host-cell entry and greater replication resulting in high viral loads and prolonged viral shedding, widespread tissue-injury, and severe inflammation leading to increased transmissibility and lethality. Furthermore, the accumulating evidence shows that multiple new variants have reduced neutralization by both, natural and vaccine-acquired antibodies, indicating that repeated and vaccine breakthrough infections may arise as serious health concerns in the ongoing pandemic.

Section: Wild-type Sars-cov-2mentioning

confidence: 99%

Emerging SARS‐CoV‐2 variants can potentially break set epidemiological barriers in COVID‐19

Parashar

Journal of Medical Virology

et al. 2021

Self Cite

“…As expected, the score was predictive independently of the pandemic waves. In fact, regardless of new emerging variants or the introduction of vaccines, COVID-19 patients continue to suffer from the same respiratory, cardiovascular, renal, digestive, and neuronal virusrelated problems, which, in turn, can all be ascribed to uncontrolled immune response (34). Since the combination of cellular parameters on which the score is based can reflect the capability of the immune system to respond to the infections, a high score always reflected a patient in critical condition and a low score always reflected a patient under mild conditions.…”

Section: Discussionmentioning

confidence: 99%

Definition of the Immune Parameters Related to COVID-19 Severity

et al. 2022

A relevant portion of patients with disease caused by the severe acute respiratory syndrome coronavirus 2 (COVID-19) experience negative outcome, and several laboratory tests have been proposed to predict disease severity. Among others, dramatic changes in peripheral blood cells have been described. We developed and validated a laboratory score solely based on blood cell parameters to predict survival in hospitalized COVID-19 patients. We retrospectively analyzed 1,619 blood cell count from 226 consecutively hospitalized COVID-19 patients to select parameters for inclusion in a laboratory score predicting severity of disease and survival. The score was derived from lymphocyte- and granulocyte-associated parameters and validated on a separate cohort of 140 consecutive COVID-19 patients. Using ROC curve analysis, a best cutoff for score of 30.6 was derived, which was associated to an overall 82.0% sensitivity (95% CI: 78–84) and 82.5% specificity (95% CI: 80–84) for detecting outcome. The scoring trend effectively separated survivor and non-survivor groups, starting 2 weeks before the end of the hospitalization period. Patients’ score time points were also classified into mild, moderate, severe, and critical according to the symptomatic oxygen therapy administered. Fluctuations of the score should be recorded to highlight a favorable or unfortunate trend of the disease. The predictive score was found to reflect and anticipate the disease gravity, defined by the type of the oxygen support used, giving a proof of its clinical relevance. It offers a fast and reliable tool for supporting clinical decisions and, most important, triage in terms of not only prioritization but also allocation of limited medical resources, especially in the period when therapies are still symptomatic and many are under development. In fact, a prolonged and progressive increase of the score can suggest impaired chances of survival and/or an urgent need for intensive care unit admission.

“…Signs and symptoms, however, can affect several organs. Other systems can be involved, such as the central nervous system (hypo-anosmia, loss of the sense of taste, speech disturbances, dizziness, alterations of the consciousness and behavior, impaired walking and maintenance of upright position, impaired hearing and vision), the cardiovascular system (alterations in hemostasis, arrhythmia, heart failure), the gastrointestinal system (nausea, emesis, diarrhea, abdominal pain), the renal system, neuromuscular (myalgia) and skin adnexa [ 26 ].…”

Section: Clinical Manifestation Of Covid-19 and Post-acute (Long) Cov...mentioning

confidence: 99%

“…The persistence of fatigue, headache, and anosmia, the onset of anxiety and a depressive state are symptoms that have recently been included in the so-called post-acute (long) COVID-19 [ 26 , 33 , 34 ].…”

Section: Clinical Manifestation Of Covid-19 and Post-acute (Long) Cov...mentioning

confidence: 99%

COVID-19 2022 update: transition of the pandemic to the endemic phase

et al. 2022

COVID-19, which is caused by the SARS-CoV-2, has ravaged the world for the past 2 years. Here, we review the current state of research into the disease with focus on its history, human genetics and genomics and the transition from the pandemic to the endemic phase. We are particularly concerned by the lack of solid information from the initial phases of the pandemic that highlighted the necessity for better preparation to face similar future threats. On the other hand, we are gratified by the progress into human genetic susceptibility investigations and we believe now is the time to explore the transition from the pandemic to the endemic phase. The latter will require worldwide vigilance and cooperation, especially in emerging countries. In the transition to the endemic phase, vaccination rates have lagged and developed countries should assist, as warranted, in bolstering vaccination rates worldwide. We also discuss the current status of vaccines and the outlook for COVID-19.