COVID-19: What you need to know.

The new SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) belongs to the family of coronaviruses, and it is a new strain of coronavirus that has not been previously identified in humans. It causes a contagious disease, which affects the respiratory system and can lead to severe complications in some cases. This virus was detected in China, then rapidly spread to almost all countries. Because of their complexity and the malignancy of the symptoms, they remain a center of interest for researchers. Herein, we provide a review in terms of transmission, clinical presentation, diagnosis, and treatment options in clinical trials of COVID-19 (coronavirus disease 2019), because readers need to update themselves regularly, and there is still much more to know about it.

Introduction

The first emergence of unidentified pneumonia was reported in Wuhan, China in December 2019 and then the Chinese Center for Disease Control and Prevention confirmed on January 3, 2020, that the disease was caused by a novel member of enveloped RNA coronavirus (SARS-CoV2), while the disease has been named COVID-19 (Mustafa and Selim, 2020) . The coronaviruses are members of the subfamily of Coronavirinae of the family of Coronaviridae, the peculiarity of this virus is a very long RNA genome (from 26 to 32 kb) (Mousavizadeh and Ghasemi, 2020). In 2003, SARS-CoV-1 presumed to spread to humans by an Intermediate host civet cat, and mortality was approximately 9.5% with R0 of 1.7–1.9 (Petrosillo et al., 2020). By 09 June 2020, a total of 7,224,364 cases of coronavirus disease, and 409,247 deaths have been reported worldwide ().

Transmission

COVID-19 at first was considered as a direct zoonosis, but it is now quickly confirmed that its transmission is from human to human, due to the number of cases started to increase exponentially (Huang et al., 2020). If a symptomatic or asymptomatic infected person breathes, sneezes, coughs, spits or talks; droplets (Aerosol) immediately fall to the ground or remain in the air for a long time, and these droplets can be inhaled by other people in the same area (van Doremalen and A. T, 2020). The virus has been shown to remain viable on fomites for a median estimate of approximately 1.1 h (Ong et al., 2020).

A vital measure to prevent the spread of the virus is by avoiding touching the hands with the eyes, mouth and nose, as the virus can be transmitted to the body through the open space of the mouth, nose, and eyes with contaminated fingers (Singhal, 2020). To avoid transmission, a surgical mask worn by the infected person or by their contacts is highly recommended. Cloth masks are not effective than surgical masks (MacIntyre et al., 2015).

However, one study confirmed that transplacental transmission may occur from pregnant women to the fetus (Vlachodimitropoulou et al., 2020). Also, the fecal-oral transmission might be possible; the virus has been detected in the stools of patients (Gu et al., 2020).

Clinical presentation

The clinical features of COVID-19 are diverse, ranging from asymptomatic state, acute respiratory distress syndrome to organ failure and the most common were fever, fatigue, dry cough, and shortness of breath. Besides, some patients experience gastrointestinal symptoms, such as nausea, diarrhea, abdominal pain, and poor appetites (jin Zhang et al., 2020).

Furthermore, an average of 7 days, the disease can progress to respiratory failure, and death; this is associated with an increase of inflammatory cytokines (IL2, IL10, TNFα etc…) (Chen et al., 2020). An increased risk of venous thromboembolism was also related to COVID-19 (Danzi et al., 2020). Regarding cutaneous characteristics, patients had an erythematous viral rash, urticaria and the most distinctive one is “COVID-toes” (Recalcati, 2020; Andina et al., 2020).

Recently, several scientific articles have reported cases of children with a multi-systemic inflammatory syndrome, sometimes critical, often referred to as an atypical form of Kawasaki disease, which affects, in particular, the heart muscle and the digestive system, have recently been highlighted. This syndrome, which affects both patients with positive and negative diagnostic tests for COVID-19, may appear a few weeks after exposure to the virus (Rao and Mrcpch, 2020). The cause of this syndrome, known as PMIS (Pediatric multi-system inflammatory syndrome), appears to be uncertain. Some of these cases suggest the possibility of a toxic shock or an atypical form of Kawasaki disease (Rao and Mrcpch, 2020).

Neurological manifestations, dizziness, muscle damage, altered awareness of taste and smell have been reported (et al., 2020). Other extrapulmonary manifestations include Myocarditis in adult and ocular manifestations consistent with conjunctivitis (et al., 2020; Doyen et al., 2020).

Diagnosis

There are two types of diagnosis. First, case by case basis, for who have symptoms or risk of disease. Second, for a voluntary screening action. Many laboratories around the world are now able to test COVID-19, but the specificity remains unknown.

Virological tests by PCR (Polymerase Chain Reaction), consist in detecting the presence of the virus. The diagnosis begins with a swab from the nasopharynx or throat; also, the virus may be detected in the blood and stool. After RNA extraction, a specific qRT-PCR analysis is carried out (Corman et al., 2020). In one study, 70% tested positive first by qRT-PCR, but the second test was negative, so the results should be confirmed by a second test (False-negative results with qRT-PCR are way more of a concern than are false-positive results) (Li et al., 2020a). Enzyme-linked immunosorbent assays (ELISA) to detect the antibody of SARS-CoV-2 have been reported (Shen et al., 2020). Commercial IgG and IgA S1 tests have lower specificity, while IgA shows higher sensitivity (et al., 2020). CT scan is only useful for diagnoses if the patient has a lower respiratory tract infection (Zhou et al., 2020). The virus was shed for a median of 14 days in one study, but it is unknown whether patients with small amounts of the detectable virus remain infectious (Hu et al., 2020).

Treatment options in clinical trials

To date, there is no vaccine or drug-specific to COVID-19. However, in light of the growing understanding of the biology of it, several drugs commonly used in other diseases have been proposed as potential treatments. A randomized controlled trial was conducted with 1063 participants, hospitalized in 10 countries, suffering from COVID-19 with the involvement of the lower respiratory tract infection. Patients were assigned either to receive standard care or to receive ten days of intravenous Remdesivir therapy. The analysis showed that Remdesivir is most beneficial for patients with severe disease and assisted by a respirator (Finberg et al., 2020). Chloroquine and hydroxychloroquine (HCQ) are antimalarials with immunomodulatory activity widely used in rheumatology (Linton et al., 2020). Numerous clinical studies conducted in China on patients treated with COVID-19 have demonstrated the efficacy of treatment with HCQ over placebo to inhibit the exacerbation of pneumonia, improve imaging data, promote a negative viral state and reduce the course of the disease in the absence of severe adverse reactions (Gautret et al., 2020a). A recent study of 36 patients in France showed that adding azithromycin to HCQ can reduce viral load (Gautret et al., 2020b). The efficacy of HCQ is controversial due to the risk of adverse events such as QTc prolongation and cardiac arrhythmias (Pastick et al., 2020). Randomized clinical trials on the safety and efficacy of tocilizumab are still in progress (ChiCTR2000029765). A study of 21 patients with severe COVID-19 showed that the use of Tocilizumab (A humanized monoclonal antibody against the IL-6 receptor) had received attention as a potential treatment, at a dose of 4 to 8 mg/kg can improve blood oxygen saturation and improve the number of lymphocytes and make it normal (Xu et al., 2020). Therefore, increasing the production of TNF can promote viral infection and cause organ damage. Indeed, in the context of COVID-19, anti-TNF therapy has been suggested as a possible treatment option, recently registered randomized trial to study adalimumab (ChiCTR2000030089) (Sallard et al., 2020). JAK inhibitors, including ruxolitinib, baricitinib, and fedratinib can inhibit NAK (promotes clathrin-dependent endocytosis for the viral invasion of pneumocytes), and may also limit the systemic inflammatory response and cytokine production by inhibiting the classic JAK-STAT pathway, The other drug currently studied in COVID-19 is rusotinib (ChiCTR2000029580) (Li et al., 2020b). On the other hand, protease inhibitor, as the name of Lopinavir-ritonavir, is used as an antiretroviral agent, did not show any suppressive viral replication in the initial randomized controlled trial (Cao et al., 2020).

Conclusion

Scientists and doctors around the world, including the United States, China, Italy, France..., are working to discover new therapies for the prevention and treatment of this deadly virus. It will be crucial to define a compelling public health strategy to prevent a future pandemic, which should not occur.

Authorship statement

The author conceived of the study, reviewed and revised drafts.