Exploring Current Advances in COVID-19: Global Perspectives on Causes, Prevention, Vaccination, and Medication

Abstract

About 10% of the global population may be infected by October 2020 with COVID-19, which is caused by the new SARS-CoV-2 contagion, the main cause of mortality in the world. This contagious outbreak has easily demonstrated that it is an epidemic. It has caused 6.25 million deaths globally and continues to be a significant issue for frugality, society, and health. Recent studies have unraveled multitudinous mysteries of SARS-CoV-2 pathogenesis and structure. Acute respiratory torture pattern (ARDS), mortality, severe pneumonia, and asymptomatic infection are all included in the illness diagnosis. Transmission occurs primarily through respiratory droplets and aerosols. COVID-19 can be averted through vaccination, mask use, hand hygiene, ventilation, and avoiding close contact. Then we examine the literature on the causes, forestalled, vaccination and efficacy, effectiveness and safety of current remedy strategies for COVID- 19, with an emphasis on antiviral agents, anticoagulants, immunomodulators, anti-inflammatory agents, antimicrobial remedy, negativing antibody curatives, Janus kinase impediments, steroids and vaccination like Pfizer, BioNTech, Spikevax, Janssen, Vaxzevria, CoronaVac, Covishield ™, BIBP/ Sinopharm, Covaxin, and analyses the colourful responses to this global epidemic worldwide, fastening on the conduct taken Worldwide and their issues.

Keywords

Introduction

Fomite transmission, touching contaminated surfaces and then the face (though less common). 

Close contact with infected individuals, especially in poorly ventilated areas. The virus enters the human body mainly via the nasal or oral route and binds to ACE2 (Angiotensin-Converting Enzyme 2) receptors on host cells, especially in the lungs, heart, kidneys, and intestines, allowing viral replication and spread throughout the body [7].

SIGNS AND SYMPTOMS OF SARS-CoV-2 COVID-19

Infections show a variety of signs and symptoms ranging from mild to severe. The most common symptom is fever, affecting about 81% of patients, followed by cough in approximately 58% of cases. Fatigue and muscle pain (myalgia) are also frequent, occurring in nearly 38% and 18% of patients, respectively. Shortness of breath (dyspnea) is observed in around 26% of patients and is more common in severe cases. Other respiratory symptoms, such as sore throat and sputum production, are also reported. Loss of smell (anosmia) and loss of taste (ageusia) are also observed, along with nasal congestion. Overall, the typical clinical picture of COVID-19 includes fever, cough, fatigue, and myalgia [8].

PREVENTION TECHNIQUES                                                         

Despite the tremendous morbidity and mortality caused by the pandemic, new variants such as Delta and Omicron have emerged and continue to pose challenges for global health management. Since SARS-CoV-2 is highly contagious and affects people worldwide, vaccination remains the most crucial method for protecting individuals from COVID-19. A vaccine is a biological substance that stimulates the immune system to recognize and combat pathogens, thereby protecting against disease. The process of administering a vaccine is known as vaccination [9]. Although vaccination does not always provide complete protection against infection, its primary goal is to prevent severe disease and reduce mortality and long-term disability. The process of vaccine development is highly complex and typically takes around 15 years under normal circumstances. However, advances in genetic sequencing, biotechnology, and molecular engineering significantly accelerated the development of COVID-19 vaccines. Due to the speed and flexibility of emerging vaccine technologies, multiple vaccine platforms were able to reach clinical use within a year of the pandemic’s onset [10]. According to Bartsch et al., a vaccine must be at least 70% effective to prevent an epidemic and 80% effective to eliminate one. In addition to efficacy, other factors such as the mode of administration, community acceptance, infection reduction potential, duration of protection, and safety must also be considered. Many SARS-CoV-2 vaccine candidates target the spike (S) protein, particularly its S1 subunit, to induce neutralizing antibodies and protective immunity. There are several types of COVID-19 vaccines, including inactivated virus vaccines, mRNA-based vaccines, live-attenuated vaccines, DNA vaccines, vector-based vaccines, and protein subunit vaccines [10,11]. Each vaccine platform possesses unique characteristics that influence its safety, efficacy, and duration of immune protection. As of February 2022, according to the WHO COVID-19 Vaccine Tracker, 146 vaccines were in clinical development and 195 were in preclinical development. By February 28, 2022, more than 10.7 billion vaccine doses had been administered globally, as reported by the WHO Coronavirus (COVID-19) Dashboard. Ongoing studies continue to investigate the immunological pathways involved in protection following COVID-19 vaccination. Understanding the type and duration of immune responses elicited by various vaccine platforms will be critical for long-term disease prevention. If any adverse effects occur following immunization, all individuals are advised to seek immediate medical attention [12].

A) mRNA-Based Vaccines

Because RNA may swiftly break down the single-stranded mRNA structure, mRNA-based vaccines are highly vulnerable to degradation, though they generate a speedy immune response by quickly translating the antigen in the target cell. Using complexing agents based on nanoparticles, including lipids and polymers, the capacity of mRNA vaccines to deliver mRNA to the cytoplasm for translation can be improved. mRNA vaccines could benefit vaccine development since they can mimic natural infections and stimulate the immune system to inhibit their spread. Some of the mRNA-based vaccines for treating COVID-19 are the Comirnaty® (BNT162b2) and Moderna vaccines (mRNA-1273) [9, 13].

1. Comirnaty ® Vaccine – Pfizer BioNTech Pfizer Inc. 

The SARS-CoV-2 contagion's full-length shaft is decoded by this mRNA-grounded vaccine, which is reprised in lipid nanoparticles and modified with two proline mutations (P2S) that are locked into the prefusion conformation to evoke antibody responses that neutralise the contagion. This vaccine, which is presently vended under the brand name Comirnaty, entered its first emergency use authorization (EUA) for COVID-19 prophylaxis from the FDA in December 2020 and approval on August 23, 2021 [14]. It offers 95% protection against COVID-19. The vaccine vials must be stored at −70 °C and have a shelf life of over 6 months. Two boluses (0.3 mL each) are administered intramuscularly, 3 weeks piecemeal, in the upper arm after mixing with saline. Heat, pain, greediness, swelling, fatigue, fever, puking, headache, myalgia, and diarrhea were the most common side effects after administration, and an Anaphylaxis response has also been reported. For people progressed over 18 times, a booster dose is given at least 6 months after the alternate vaccination. The Comirnaty ® vaccine is also extremely effective at precluding the spread of the B.1.351 variant [15, 16]. 

B) Inactivated Virus Vaccines 

An inactivated contagion vaccine can be created by cultivating a contagion in culture and inactivating it with a substance that permits the stable expression of native antigenic epitopes.

Inactivated vaccines use dead contagions as the immunogen to boost protective responses. Although creating inactivated contagions is likely safer, it frequently only offers temporary protection and requires regular boosters. Below is a discussion of the vaccines created by Sinovac, Sinopharm, and Bharat Biotech [17].

1) CoronaVac Vaccine – Sinovac Biotech 

It doesn't need to be frozen, and it can be stably stored at 2 – 8 ? C for up to 3 times. It can be mixed and matched with other vaccines, such as COVID-19 mRNA vaccines (Pfizer or Moderna) or COVID-19 vector vaccines (COVISHIELD or Janssen). It was granted marketing authorization on 6 February 2021 by the China National Medical Products Administration (NMPA). It has shown 83.5 efficacy after 14 days or further from the alternate cure. It involves two 0.5 mL administrations in the deltoid muscle at 2 – 4-week intervals between the first and alternate boluses. The side effects include headaches, fatigue, muscle pain, and vomiting [18].

2) BBIBP- CorV Vaccine- Sinopharm

The BBIBP-CorV is an inactivated viral vaccine created by Sinopharm in association with the Chinese Center for Disease Control and Prevention and the Beijing Institute of Biological Products. It was created by employing Vero cells to cultivate the contagion and β-propiolactone to further inactivate it. Analogous to the inactivated polio vaccine, aluminium hydroxide was employed as the adjuvant. A 0.5 mL lozenge of sterile phosphate-softened saline is contained in each prefilled hype. On December 31, 2020, the China National Medical Products Administration approved its use [19]. Shown that this vaccination has good inheritable stability and is significantly defensive against COVID-19. It should be administered in two boluses spaced three to four weeks piecemeal in the deltoid muscle to those who are at least eighteen years old. The vaccine can be kept between 2 and 8 °C, and its total effectiveness was set up to be 79%. The most common side effects recorded were headaches, weariness, soreness, fatigue, and injection point pain [20].

3. Covaxin (BBV152) Vaccine-

Bharat Biotech, in collaboration with the Indian Council of Medical Research, National Institute of Virology (ICMR-NIV), Bharat Biotech created Covaxin, the country's domestic COVID-19 vaccine. The use of Covaxin to help with COVID-19 was authorised by the medicines controller general of India (DCGI) on January 3, 2021 [21]. Covaxin was created by using β-propiolactone to inactivate the whole contagion. Only grown-ups over the age of 18 are eligible for the vaccination, which must be given in two 0.5 mL boluses separated by 28 days [22]. It comes in multi-dose vials and does not bear reconstitution or freezing instructions. The drug is fitted intramuscularly and is stable between 2 and 8 °C. Also, it has demonstrated efficacy against the Beta (B.1.351) and Delta (B.1.617.2) genotypes. Adverse symptoms, including injection point pain, itching, headache, fever, body pangs, nausea, and vomiting, have a 77.8% effectiveness rate [21,22].

C) Vaccines Based on Viral Vectors

In a viral vector-ground vaccine, the pathogenic antigen-generating gene is reproduced into either non-replicating or replicating viral vectors. Without the need for an adjuvant, a vaccine made from viral vectors can be produced quickly. Using viral-ground technologies, COVID19- Shield, Sputnik V, and Ad26. COV-2 S has been developed to help with COVID-19 infections [23].

1) Covishield (ChAdOx1 nCoV19) 

The AstraZeneca Covishield (ChAdOx1nCoV19) was developed by Oxford University in the United Kingdom and the British-Swedish company AstraZeneca. It is capitalized under the Names Vaxzevria and Covishield. It is a chimpanzee adenovirus-vector vaccine that encodes for a full-length S-protein of SARS-CoV-2 2 and is produced in genetically modified mortal embryonic kidney (HEK) 293 cells. The Serum Institute of India at Pune is one of its manufacturing sites [24]. It is administered intramuscularly in the upper arm for people above 18 years of age in two shots of 0.5 mL each, 3 months piecemeal, and has shown 90% efficacy. Fatigue, headache, fever, vomiting, chills, diarrhea, and myalgia were the common side effects after vaccination, and anaphylaxis has also been reported. Schultz reported that the cases developed severe thrombosis and thrombocytopenia after entering the first course. The five healthcare workers progressed 32 to 54 times revealed venous thrombosis and thrombocytopenia 7 to 10 days after the original cure. This shows that the thrombocytopenia was caused by a rare vaccine-related type of robotic heparin-induced thrombocytopenia. It is 81% effective against the niche variant (lineage B.1.1.7) and 61% effective against the Delta variant (lineage) [25].

2, Sputnik V (GAM- COVID-Vac)

Vaccine-Kamala, the Russian Defense Ministry, and the Gamaleya Research Institute of Epidemiology and Microbiology developed the Sputnik V Gam COVID vaccine, which is generated from rAd type 26 (rAd26) and rAd type 5 (rAd5) and contains the entire S-protein of SARS-CoV-2. On 11 August 2020, the Russian Federation’s Ministry of Health approved this, the world’s first registered combination vector vaccination, for administration. Sputnik V is the trade name under which it is sold [26]. The name of the vaccine was chosen to honor the launch of the world’s first artificial Earth satellite in 1957. It is administered in two 0.5-mL doses into the deltoid muscle. 21 days apart and stored at −18.5 ?C (liquid form) and 2–8°C (dry form). The effectiveness of the vaccine for symptomatic COVID-19 is 91.6%, preventing the disease completely. Some of the side effects are body soreness, joint pain, chills, injection site pain, redness, fever, and headache [27].

Additional COVID-19 Vaccines:

The Sinopharm vaccines are two-dose, inactivated virus vaccines that are administered via IM injection. These vaccines are comparatively favorable since they can be disseminated and maintained at regular refrigerated temperatures. They also contain an aluminum hydroxide adjuvant to stimulate the immune system. However, compared to Pfizer and Moderna's vaccines, Sinopharm's data reveal an efficacy of roughly 79% for BB IBP-CorV and 72.8% for WIBP CorV. However, existing data indicate that all recipients develop an effective humoral immune response when both doses are given. Additionally, the current research shows that their vaccines can result in notable levels of neutralizing antibody titers in rats, mice, guinea pigs, rhesus macaques, and pigs. Although the research currently supports the effectiveness of immunizations, there have been conflicting reports about vaccines from China because this is a rapidly shifting field, impeding these vaccinations' transparency, which could cause people to hesitate [28].

Due to SLNs' many benefits, including tailored drug release, cost, and improved stability of pharmaceutical goods, their widespread use has grown quickly. Since the beginning of the COVID-19 pandemic, research on SLNs has increased, and various COVID-19 mRNA vaccines have been developed using lipid nanoparticles as a drug delivery mechanism. However, the fact that both lipids and nucleic acids have negative charges and are consequently not ionizable has caused problems when employing SLNs to carry nucleic acids. Both the Moderna and Pfizer BioNTech (Pfizer) mRNA vaccines, which employ ionizable cationic lipids to encapsulate the nucleoside-modified mRNA encoding a spike protein of SARS-CoV2, have made use of this technology [29,30].

TREATMENT STRATEGIES

Anti-inflammatory agents, hyperinflammation, and cytokine storm are key drivers in the progression of COVID-19 to severe interstitial pneumonia, acute respiratory distress syndrome (ARDS), and coagulopathies. Therefore, identifying therapies that can target both the virus and the resulting. Possible spelling mistake found. It is critical for effective COVID-19 management. Anti-inflammatory treatments used in this context include corticosteroids, intravenous immunoglobulin (IVIG), Janus kinase (JAK) inhibitors, colchicine, and glucocorticosteroids [31].

1. Glucocorticoids 

COVID-19 is a condition associated with multi-organ damage and a strong inflammatory response. In severe cases, elevated levels of inflammatory markers are frequently observed. Glucocorticoids are powerful anti-inflammatory drugs and, despite initial debate about their role in COVID-19 therapy, evidence now shows notable benefits in certain patient groups. Recent studies indicate that glucocorticoids (such as dexamethasone) are effective in hospitalized patients requiring respiratory support, particularly when treatment is initiated after the first week of illness, at which point immune-mediated damage predominates and active viral replication plays a lesser role. However, no benefit—and even potential harm—was observed in patients who did not require respiratory support (oxygen therapy or invasive mechanical ventilation) [32]. It remains unclear how glucocorticoids affect the risk of developing long-term or post-COVID. Due to their potent anti-inflammatory effects, glucocorticoids may not only reduce mortality but also slow disease progression—for example, preventing the need for invasive mechanical ventilation in patients treated with oxygen alone. According to a recent study, hospitalized patients who took oral dexamethasone were less likely to have ongoing symptoms at an 8-month follow-up. However, more investigation is required to ascertain whether glucocorticoids can indeed lower the risk of long-term or post-COVID [33].

2. IVIG, or intravenous immunoglobulin 

IVIG is a blood-derived product that is typically used as a supportive treatment. It is made from the plasma of healthy donors. Polyclonal immunoglobulin G, which is commonly utilized as an immunotherapeutic molecule to treat various autoimmune and inflammatory illnesses, is present in IVIG. IVIG may be used to treat patients with severe COVID-19 according to the positive outcomes of earlier studies on MERS and SARS. IgG antibodies obtained from recovered COVID-19 patients in the same city or the surrounding area can be used to increase the effectiveness of IVIG by increasing the likelihood of neutralizing SARS-CoV-2. High-dose IVIG treatment is thought to boost passive immunity and modulate immunological inflammation. How IVIG benefits patients with severe COVID-19 is still unknown. Shi et al. found that severe COVID-19 patients can be treated without the need for extensive supportive care or mechanical ventilation if plasma exchange and IVIG are started on time. IVIG should therefore be provided before the onset of systemic damage, as this is the primary factor influencing the outcome of IVIG therapy [34].

3. Janus Kinase Pathway Inhibitors (JAK):

In COVID-19 patients, the presence of proinflammatory and chemoattractant cytokines indicates activation of the Janus Kinase–Signal Transducer and Activator of Transcription (JAK-STAT) pathway. Ruxolitinib was the first JAK inhibitor to receive authorization. Reports suggest that it is generally well-tolerated, with minimal side effects. Preliminary findings suggest that combining JAK inhibitors with Remdesivir may help shorten recovery time in hospitalized patients. Serum levels of proinflammatory cytokines and chemokines—such as IFN-γ, TNF-α, IP10, G-CSF, IL-2, IL-6, IL-8, IL-9, IL-10, and IL-17 are elevated in patients with severe COVID-19 and show a strong correlation with disease progression [35]. The JAK/STAT signaling pathway regulates many inflammatory cytokines and growth factors by transmitting signals from cell surface receptors to the nucleus, thereby influencing hematopoiesis, lactation, immune function, and mammary gland development. JAKs are tyrosine kinases that attach to the cytoplasmic domains of type I and II cytokine receptors. When a ligand binds to its receptor, JAKs are activated, which in turn recruit and phosphorylate STATs. These cytokines are crucial for triggering and coordinating both innate and adaptive immune responses, but in COVID-19, they may also contribute to uncontrolled inflammation and tissue injury. The involvement of the JAK/STAT pathway in cancer and autoimmune diseases has been widely documented, which makes its inhibition an attractive therapeutic strategy. They have already shown effectiveness in several immune-mediated inflammatory disorders, including rheumatoid arthritis (RA), myelofibrosis, and polycythemia Vera. Since severe COVID-19 is closely linked to SARS–CoV–2–driven hypercytokinemia and inflammation, several JAK inhibitors— such as baricitinib, ruxolitinib, tofacitinib, and nerizutinib— have demonstrated significant benefits in improving outcomes among hospitalized COVID-19 patients. Their therapeutic effect arises from suppressing virusinduced immune activation and inflammatory signaling [36].

A. Baricitinib

Baricitinib is a selective JAK1/JAK2 inhibitor that interferes with cytokine and growth factor receptor signaling, thereby dampening downstream immune cell activity. It is approved for the treatment of rheumatoid arthritis (RA) and has demonstrated effectiveness in clinical studies involving RA patients. The drug is well absorbed when taken orally, making it highly bioavailable and generally well tolerated. In COVID-19, cytokine signaling pathways such as IL6, IL-2, IL-10, IFN-γ, and GM-CSF become unregulated during hyperinflammatory states; baricitinib counteracts these pathways and helps mitigate the inflammatory response [37].

B. Tofacitinib

Tofacitinib is an orally administered JAK inhibitor that suppresses inflammatory cytokines, including IL-2, IL-4, IL-6, and IL-7, by targeting JAK1 and JAK3(L), and is approved for the treatment of autoimmune disorders and rheumatoid arthritis. Evidence from multiple studies indicates that tofacitinib therapy can be safely continued in patients with COVID-19. The cumulative rate of death or respiratory failure by day 28 was 18.1% in the tofacitinib group compared with 29.0% in the placebo group. Notably, 28-day all-cause mortality was significantly lower in patients receiving tofacitinib than those on placebo (2.8% vs 5.5%). Another study by Roman et al., including 62 patients with severe COVID-19, demonstrated that patients treated with tofacitinib had lower mortality and reduced rates of ICU admission compared with the control group (16.6% vs. 40.0% and 15.6% vs 50.0%, respectively) [38].

C. Ruxolitinib  

Ruxolitinib, an inhibitor of JAK1 and JAK2 protein kinases, can reduce cytokine production linked to conditions such as myelofibrosis, polycythemia vera, and acute graft-versus-host disease, which shares similarities with SARS-CoV-2 infection. Its antiviral activity has also been demonstrated against HIV and Epstein–Barr virus. Because ruxolitinib has proven effective in treating diseases associated with hyperimmune syndromes, it has been applied in the management of COVID-19. Moreover, a multicenter study involving 43 patients with COVID-19 pneumonia reported positive outcomes with ruxolitinib. In this trial, 90% of patients receiving ruxolitinib showed improvements on computed tomography by day 14, compared with 61.9% in the placebo group. Three patients in the control group died from respiratory failure, resulting in a 28-day mortality rate of 14.3%, while no deaths occurred in the ruxolitinib-treated group. These findings suggest that ruxolitinib may accelerate clinical recovery in COVID-19 patients [39].

Anti-Viral Agents 

Antiviral medicines are drugs that stop the contagion from multiplying inside the body. In COVID-19, these medicines target different stages of the SARS-CoV-2 contagion life cycle — similar to contagion entry, replication, or release — to reduce the quantum of contagion in the body (called the viral cargo). Antiviral medicines can directly interfere with the replication and proliferation of the contagion in host cells, thereby reducing viral cargo and transmission. Antiviral agents are small molecules that act as impediments to different stages of the contagion life cycle. “The main antiviral agents reported against COVID-19 include polymerase inhibitors, protease inhibitors, nucleoside and nucleotide rear transcriptase inhibitors, entry and uncoating impediments, and other antiviral medicines [40]. 

1. Polymerase inhibitors :

The main polymerase inhibitors for COVID-19 are Remdesivir, Favipiravir, and Molnupiravir. Remdesivir has been linked as one of the most promising antiviral agents tested for the treatment of COVID-19 [41].

1) Remdesivir  is an adenosine analog that enters the host cell as a monophosphoramidate prodrug and is also metabolized into an adenosine triphosphate (ATP) analog. It targets the RNA-dependent RNA polymerase (RdRp) enzyme of the contagion, blocking viral replication by causing unseasonable termination of RNA recap. This medicine exhibits broad- diapason antiviral activity against several contagion families, including paramyxoviruses, pneumoviruses, filoviruses, and coronaviruses such as MERS-CoV and SARS-CoV [42]. " Remdesivir treatment for three days was set up to be safe and reduced the threat of hospitalization or death by 87 compared to the placebo in the enrolled cases". Studies have shown that treatment with remdesivir shortens the recovery time of adults rehabilitated with COVID-19 and lower respiratory tract infections. Still, some exploration, including a multicenter trial conducted in 10 hospitals in Hubei, China, showed no statistically significant difference in the Remdesivirtreated COVID-19 cases' clinical condition in comparison to usual care. Likewise, experimenters explored the combination of baricitinib and remdesivir in rehabilitated COVID19 cases [43]. The results indicated that the combination remedy was more effective than remdesivir alone in reducing recovery time and improving clinical symptoms. Recently, the National Institutes of Health guidelines suggested that combining Remdesivir with antiinflammatory medicines such as Tocilizumab, corticosteroids, and Baricitinib can increase the benefit observed across all endpoints in cases with pneumonia and on oxygen support [44].

2) Favipiravir 

An antiviral drug provides antiviral goods against a contagion by specifically inhibiting its  RNA polymerase variety of RNA contagions. According to clinical exploration, regular probative care combined with early recovery times was vastly improved by oral favipiravir monotherapy in mild-to-moderate COVID-19 cases compared with standard probative care alone. Favipiravir is a broad-based antiviral medicine that acts as a picky asset of viral RNAdependent RNA polymerase ( RdRp), an enzyme essential for the replication of RNA viruses, including SARS-CoV-. Inside the host cell, favipiravir is converted into its active form, favipiravirribofuranosyl5 ′ triphosphate ( favipiravirRTP), which is honored by the viral RdRp and incorporated into the growing viral RNA chain. This objectification leads to unseasonable chain termination or the preface of murderous mutations, eventually inhibiting viral RNA conflation and replication. During the COVID-19 epidemic, favipiravir was repurposed and evaluated in several clinical trials, showing potential benefits in reducing viral load and shortening recovery time in cases with mild to moderate COVID-19. Still, its efficacy in severe cases remains limited, and further large-scale studies are demanded to confirm its overall clinical effectiveness [45].

2. Protease Inhibitors

In COVID-19, Lopinavir was studied because it's a protease inhibitor — it blocks the viral protease enzyme that the infection needs to cut large proteins into smaller functional pieces needed for replication. Scientists hoped it might also block the main protease (Mpro) of SARSCoV-2 2, which is analogous to the one set up in HIV. Lopinavir/ ritonavir may be more effective when combined with other antiviral treatments. In one study, four COVID-19 cases entered a combination remedy that included lopinavir/ritonavir, arbidol, and Shufeng Jiedu Capsule (a traditional Chinese drug). The pneumonia-related symptoms of three cases showed significant enhancement. Still, the efficacy of this combination remedy requires further studies to be verified [46]. Lopinavir has a short half-life; therefore, to increase its half-life, it's used together with Ritonavir. Ritonavir, a cytochrome CYP3A4 substrate, inhibits the metabolism of Lopinavir by inhibiting cytochrome P450 and functions as a pharmacokinetic enhancer of Lopinavir. Ritonavir/ Lopinavir indicated antiviral goods against MERS-CoV and SARS-CoV1 by inhibiting 3- chymotrypsin- suchlike protease activity [47]. 

3. Nucleoside and nucleotide reverse transcriptase inhibitors

Azvudine (FNC) is a nucleoside reverse transcriptase inhibitor with broad-spectrum antiviral activity, including activity against HIV-1. FNC was approved by the National Medical Products Administration (NMPA China) for AIDS treatment on 21 July 2021. Clinical trials have also evaluated FNC for COVID-19 treatment. In one study, oral FNC (5 mg, once daily) cleared the virus in COVID-19 patients, with viral RNA turning negative in approximately 3.29 ± 2.22 days, demonstrating its potential effectiveness against SARS-CoV-2. Another clinical trial in China showed that FNC shortened the time to viral RNA negativity compared with standard antiviral drugs in patients with mild to moderate COVID-19. These findings suggest that FNC is effective against COVID-19, though larger clinical trials are needed to confirm its efficacy.

Recently, the NMPA conditionally approved FNC for treating common COVID-19 in adults on 25 July 2022(122). Azvudine demonstrates excellent oral bioavailability, approximately 82.7%, in animal models, suggesting efficient absorption in humans [48]. Azvudine has demonstrated a favourable safety profile in clinical trials. Reported adverse effects are generally mild and transient, with no significant hepatotoxicity observed. This makes it a promising option for patients with comorbidities. Azvudine’s efficacy was comparable to that of nirmatrelvir ritonavir (Paxlovid) in hospitalized COVID-19 patients. Both treatments showed similar outcomes in terms of clinical improvement and mortality rates. However, Azvudine was associated with a lower incidence of platelet decline, a side effect noted more frequently with Paxlovid. Aziudine’s mechanism involves the inhibition of viral RNAdependent RNA polymerase (RdRp), a crucial enzyme for viral replication. By terminating RNA chain elongation, it effectively halts the propagation of the virus within the host.

Azvudine stands out as a broad-spectrum antiviral agent with demonstrated efficacy against HIV, HCV, EV71, and SARS-CoV-2. Its favorable pharmacokinetic properties, combined with a robust safety profile, make it a valuable addition to the antiviral therapeutic arsenal Ongoing and future studies will further elucidate its role in treating various viral infections [49].

4. Entry and uncoating inhibitors

Entry and uncoating inhibitors are classes of antiviral drugs that block the early stages of viral infection — specifically, the entry of the virus into the host cell and the release (uncoating) of the viral genome inside the cell. To prevent SARS-CoV-2 from entering human cells, mainly by blocking the interaction between the viral spike (S) protein and the ACE2 receptor on host cells, or by interfering with the membrane fusion process. To block the release (uncoating) of viral RNA once the virus enters the cell. However, SARS-CoV-2 uncoating mechanisms differ from those of influenza or enteroviruses, and traditional uncoating inhibitors (like amantadine or rimantadine) do not work effectively against SARS-CoV-2. Drugs that are used as entry and uncoating inhibitors are Arbidol, Camostat mesylate, Nafamostat mesylate, etc [50].

Arbidol

Arbidol is a non-nucleoside antiviral agent that prevents viral entry into host cells by inhibiting the fusion between the viral lipid envelope and the host cell membrane (wang L) s1. In addition, it enhances the host immune response by inducing the production of interferons (IFNs) and activating macrophages. Arbidol has been shown to have antiviral properties against a number of viruses, including influenza, adenovirus, hepatitis C and B viruses, and respiratory syncytial viruses. Arbidol can inhibit SARS-CoV-2 infection, with an EC?? value of 4.11 μM. A retrospective trial conducted by Deng and coworkers revealed that the negative conversion rates of SARS-CoV-2 tests on days 7 and 14 were significantly higher in patients treated with a combination of Ritonavir/Lopinavir plus oral Arbidol compared to those treated with Ritonavir/Lopinavir alone. Moreover, the combination therapy remarkably improved chest CT scan results after 7 days of treatment [51].

Camostat mesylate

Camostat mesylate, a serine protease inhibitor, is a potent inhibitor of TMPRSS2 and has been proposed as a potential antiviral agent against SARS-CoV-2. Both in vivo and in vitro studies have demonstrated that Camostat mesylate blocks virus–cell membrane fusion, thereby inhibiting viral replication [52]. 

Amantadine

An antiviral drug traditionally used for the treatment of influenza A acts by blocking the early stage of viral replication. Due to its lipophilic and alkaline physicochemical properties, amantadine can cross the lysosomal membrane and prevent the release of viral RNA into host cells, thereby inhibiting viral replication. Therapeutic potential in COVID-19 patients. Interestingly, a preliminary study has suggested that adamantane derivatives may exert protective effects against COVID-19; however, these findings are limited by the small sample size and lack of large-scale clinical validation, indicating the need for further well-controlled studies to confirm their efficacy against SARS-CoV-2. In addition, Enfuvirtide, a fusion inhibitor peptide originally developed for HIV-1, has been proposed as another potential antiviral candidate for COVID-19 treatment. Enfuvirtide functions by blocking the fusion between the viral envelope and the host cell membrane, thereby preventing viral entry into the cell [53]. 

CONCLUSION

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, has emerged as one of the most significant global health challenges of the 21st century. Since its initial outbreak in Wuhan, China, in late 2019, the virus has spread rapidly across continents, resulting in substantial morbidity, mortality, and socioeconomic disruption. Continuous global research efforts have significantly advanced understanding of the virus’s structure, transmission dynamics, and prevention strategies. The disease primarily spreads through respiratory droplets and aerosols, making preventive measures such as mask-wearing, hand hygiene, social isolation, and proper ventilation highly effective in controlling transmission. Vaccination has proven to be the most powerful tool for mitigating the spread and severity of COVID-19. Different vaccine platforms, including mRNA-based vaccines (Pfizer-BioNTech, Moderna), viral vector vaccines (Covishield, Sputnik V, Janssen), and inactivated vaccines (Covaxin, CoronaVac, Sinopharm), have demonstrated strong immunogenicity and acceptable safety profiles. These vaccines have substantially reduced hospitalization and death rates globally. However, the emergence of new variants like Delta and Omicron highlights the need for continuous vaccine updates and booster programs to sustain immunity. In addition to vaccination, various therapeutic agents have been explored to treat COVID-19 and manage its complications. Antiviral drugs such as Remdesivir, Favipiravir, and Molnupiravir target viral replication, while anti-inflammatory and immunomodulatory drugs—such as corticosteroids, intravenous immunoglobulin (IVIG), and Janus kinase (JAK) inhibitors—help in controlling hyperinflammation and cytokine storms. These treatment strategies have significantly improved patient recovery and reduced mortality rates. Despite these advances, equitable access to vaccines and therapeutics remains a challenge, particularly in developing nations. Strengthening healthcare infrastructure, encouraging global collaboration, and investing in pandemic preparedness are essential for preventing future outbreaks. Finally, a combination of preventive measures, effective vaccination, timely therapeutic interventions, and global cooperation is crucial to controlling COVID-19 and minimizing its long-term impact on public health and the global economy.   

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