As the world grapples with coronavirus pandemic, researchers are racing against time to find an immediate cure for the disease and also develop a vaccine against the new respiratory pathogen.
While the development of a vaccine is at least a year away, an international collaborative effort by researchers and medical professionals is now focused on testing the efficacy of a cocktail of antiviral drugs to treat the Covid-19 patients.
The challenge before the healthcare professionals is all the more daunting because there are no approved treatments as of now, nor are there any approved vaccines for the new strain.
Despite advancements in genomics and improved global coordination, vaccine development still remains an expensive and lengthy process.
Once a coronavirus infection is confirmed, the present line of treatment is mainly supportive, making sure the patient gets enough oxygen, managing the fever and using a ventilator to push air into the lungs if necessary.
Patients with mild cases are told to rest and drink plenty of fluids while the immune system does its job and heals itself. Most people with mild infections recover in about two weeks.
Symptomatic care for patients with mild infection and optimised supportive care for those with severe disease are the key components of the treatment intervention now.
Cocktail of drugs
A number of drugs are currently being tested as potential treatments, including an antiviral medication called remdesivir, which appears to be effective in animals and was used to treat the first American patient in Washington State.
In animal models, scientists have found that remdesivir, which was developed to treat Ebola, can knock down similar coronaviruses, such as the ones that cause Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS).
Despite its use in an emergency situation, the drug “has not been demonstrated to be safe or effective for any use,” Gilead Sciences, the American biopharmaceutical company that is developing the drug, said in a statement.
The California-based company has started clinical trials in China after peer-reviewed journals showed its antiviral candidate having positive results. It is working with governments to provide the drug as an emergency treatment in the absence of other options.
Similarly, another group of researchers found that chloroquine —a widely used anti-malarial and autoimmune disease drug— was also effective in stopping the virus from spreading in human cells in the lab.
The research findings were published in the journal “Cell Research”. Interestingly, both the drugs were effective at low concentrations and were not toxic to human cells.
Since remdesivir and chloroquine have shown a satisfactory safety track record and are effective against various ailments, the process to assess their efficacy in Covid-19 patients is being fast-tracked.
A World Health Organization (WHO) assessment described remdesivir as the “most promising candidate” against COVID-19.
A combination of anti-HIV drugs, lopinavir and ritonavir, was used on a coronavirus-infected elderly Italian couple at a hospital in Jaipur.
“The female has tested negative now and her condition has improved while the 69-year-old male is still positive and on non-invasive ventilation (NIV) support,” said Dr DS Meena, Medical Superintendent of SMS Hospital at Jaipur.
However, no conclusion can be drawn with a single patient experiment.
In another instance, the researchers have said that Camostat mesylate, a drug approved in Japan for use in pancreatic inflammation, could work to combat Covid-19, as it was found to block the entry of the virus into lung cells.
The 2019-nCoV belongs to Betacoronavirus family which also contains SARS-CoV and MERS-CoV. Several drugs, such as ribavirin, interferon, lopinavir-ritonavir and corticosteroids, have been used in patients with SARS or MERS, though the efficacy of some drugs remains controversial.
A Japanese drugmaker Takeda Pharmaceutical Co. has announced that it was developing a new coronavirus drug derived from the blood plasma of people who have recovered from Covid-19.
Its approach is based on the idea that antibodies developed by recovered patients might strengthen the immune system of new patients.
To turn that into a drug, the plasma is harvested, tested for safety, and purified to isolate those protective antibodies. When injected into a new patient, the “plasma-derived therapy” provides “passive immunity” until the patient’s immune system can generate its own antibodies.
Viruses are not as easy as bacteria to treat. That is because they are very diverse, with unique characteristics that can’t be targeted with a broad-spectrum drug like a general antibiotic.
Also, viruses hijack the human cellular machinery to create proteins that help them to replicate. So, targeting viruses while not damaging human cells can prove very challenging.
Once researchers identify the specific protein on the outside of human cells that the new coronavirus uses to gain entry, then they will be able to find small molecules that can block the binding of the virus into cells.
After the SARS outbreak in 2003, it took researchers about 20 months to get a vaccine ready for human trials. By the time of the Zika outbreak in 2015, the vaccine development timeline was down to six months.
Now, they hope that lessons learnt from past outbreaks will help cut the timeline further. Several pharmaceutical research companies are working on vaccine candidates.
India has become the fifth country in the world, after the US, Japan, Thailand and China, to successfully isolate the virus strain. However, development of vaccine will take at least two years, the Indian Council of Medical Research (ICMR), the apex health research body, said.
The isolation of the virus is the first step towards expediting the development of drugs, vaccines and rapid diagnostic kits. The scientists at the National Institute of Virology (NIV), Pune, have isolated 11 strains of the Covid-19. Still, they will need between 18 months and two years to develop a vaccine even if the clinical trials are expedited.
While the immediate response is crucial, longer-term solutions come from essential research into this novel virus.
“Coronavirus was very difficult to isolate. The strains are the prerequisite for conducting any research related to viruses,” said Raman R. Gangakhedkar, head of the epidemiology and communicable diseases division at the ICMR.