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COVID-19 (Coronavirus Disease-2019) is a highly contagious respiratory disease caused by a novel coronavirus named SARS-CoV-2. The perilous coronavirus has sent a shiver down the spines. This virus belongs to family of coronaviruses. They infect mostly bats, pigs, and small mammals. But due to their ability to mutate, they can jump from animals to humans, a process called zoonosis, and then from one human to another. The COVID-19 was discovered in Wuhan, China in December 2019 and has spread globally. Seven members of coronavirus family have infected humans including this new virus. Four of these are responsible for common colds but two others were among the deadliest human infections i.e. Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). COVID-19 is less deadly as compare to related pathogen, SARS and MERS, but it spreads more easily from one person to another.

Viruses reproduce inside the human cells as they are obligatory intracellular parasites. Human cell, once infected with virus, produces viral proteins to create new viruses, then the viruses come out of the cell and infect other cells. SARS-CoV-2 infects the lower respiratory tract. Symptoms include fever, cough, shortness of breath and can lead to pneumonia in severe cases. Other symptoms include sore throat, headache, fatigue, and nausea, with diarrhea and vomiting. Some individuals become mildly ill for few days and recover, and some are infected but do not get sick, but they might spread their infection. The rate of mortality ranges between 2% to 4.5% according to the confirmed cases and casualties, which is changing every day. Therefore, the exact rate cannot be determined until the figures of all people who have been infected including those who never had symptoms or had a flu like illness but were not tested for COVID-19. The disease is still deadlier than seasonal flu which has a mortality rate of 0.1%. People get sick between 2-14 days after infection but in a report, illness appeared after 27 days. According to Chinese researchers, an average incubation period is 5.2 days.

A global arms race for a coronavirus vaccine is underway. China, Europe and the US are trying their best to become the first to produce a vaccine against coronavirus

Although, to eradicate any disease, vaccine is the ultimate solution, but it will need time and combined efforts of scientific community. Currently, scientists around the world are scrambling to find a drug that can kill the lethal virus. Here, I am going to discuss few drugs which are serious contenders against coronavirus.

Remdesivir

It is an anti-viral drug which was developed against Ebola. It inhibits the virus production by paralyzing the RNA polymerase enzyme. It has been published in esteemed scientific journal Nature that remdesivir is highly effective in the control of novel coronavirus (SARS-CoV-2) infection in vitro (means in the lab). Remdesivir is in phase III clinical trial and first results were released on 29th April and good news is that these first results proved that Remdesivir is effective against COVID-19. The results of second trial with a different group of patients are expected to come in late May. The drug is also going to be used in combination with Chloroquine, an anti-malarial drug. The combination is under trial and required more studies before we can use it in patients.

Chloroquine phosphate

It has been widely used as an anti-malarial drug as well as an autoimmune disease drug. Recently, it was tested in China and South Korea on COVID-19 patients and results were promising against the virus. The Wuhan institute of Virology also suggested that this drug is highly effective in lab tests. Officials of both countries believe that drug has potential to treat COVID-19 patients. Studies have shown that Chloroquine can inhibit the virus infection by increasing pH of the area of cells where virus attacks and makes it difficult for virus to replicate. It also interferes with viral entry into the cells. Experts in Italy, Netherland, US and France are working on this drug to be used against coronavirus.

Hydroxychloroquine

This is another form of Chloroquine reported in Cell Discovery (published by Nature) by Chinese scientists suggesting that it shares similar chemical structures and mechanisms as well as its less toxic. , Hydroxychloroquine is also in phase III clinical trials and results are expected to come in a couple of months. Professor Didier Raoult from Marseille, France has recently published an article showing that COVID-19 patients treated with Hydroxychloroquine and combination of Hydroxychloroquine and Azithromycin have seen a rapid and effective healing process. French health officials are now planning on a larger trial of the drug. Although, the head of clinical care for WHO’s emergence program, Janet Diaz stated that more clinical trials are required to confirm efficacy and safety of the drug.

Lopinavir/ritonavir

It is an anti-HIV drug used in the individuals containing virus to inhibit its progressing into AIDS. A group of scientists in Asan Medical Center, Seoul, South Korea has shown the antiviral activity of lopinavir/ritonavir against SARS-CoV-2 in vitro. This drug is a protease inhibitor that blocks the replication of the virus. According to Chinese media, it was successfully used to treat patients of coronavirus, but clinical trials have not been proven scientifically yet.

Favipiravir

Favipiravir was used by the doctors in China against coronavirus in 80 patients in Wuhan and Shenzen. Doctors declared that it was clearly effective in patients. It is an active ingredient in a flu drug called Avigan. The drug neutralizes an important enzyme (RNA polymerase) that is used by the virus to reproduce. The drug reduced lung damage and enhance recovery without any specific side effects.

Ivermectin

Researchers have seen promising results of head lice drug, Ivermectin, against COVID-19 in lab studies. Ivermectin is anti-parasitic drug.

Vaccines

A global arms race for a coronavirus vaccine is underway. China, Europe and US are trying their best to become the first to produce a vaccine against coronavirus. Researchers at Academy of Military Medical Sciences have developed the vaccine candidate and recruiting volunteers for clinical trials. Moreover, scientists at Oxford University, UK, will start a safety trial next month on humans to develop UK’s first vaccine against SARS-CoV-2. Importantly, the first human trial of a vaccine against pandemic coronavirus has started in Seattle, the US. Eight individuals were injected with different doses. This vaccine cannot infect or spread COVID-19 as it is just a harmless genetic code (messenger RNA) copied from the COVID-19. The code is for a spike-like protein on the virus surface which attaches to the human cells and helps virus entry into the cells. Scientists are hopeful to observe immune response against virus, but it will take many months to know about the vaccine response and safety tests before it will be available for public.

Either it is a drug or a vaccine, it will take from weeks to months to develop. Therefore, till the availability of a drug or vaccine, the only solution against the spread of this lethal virus is containment and isolation. Social distancing is required to flatten the transmission curve.

The writer is PhD-Molecular & Cellular Biology (University of Strasbourg France) Postdoc (University of Pennsylvania, America).