Dr. Deepak Bhardwaj
A microorganism has taken the world by storm, spreading like wildfire to new epicentres around the world. As it left Asia, and leaped towards Iran and Europe, it threatens to infect several lakhs in the US. India is bracing to deal with larger numbers as SARS-CoV-2 is no longer just an unwelcome visitor from abroad but is moving quickly through local communities. Efforts to contain it at every step by implementing quarantines and community lockdowns are frustrated by the fact that for every confirmed case in a community, there are several with undetected infections. At the same time, the scientific community around the world is putting their brains together to deal with this menace in a multi-pronged way. As they come up with preventive methods to recycling drug therapies and new vaccine development, a compressed timeline is making the task more challenging.
While efficacy has not been established for any drug therapy, several known therapies are being considered in the absence of sure-shot treatment plans. Popular antimalarial drugs Chloroquine and Hydroxychloroquine are being used to stop the virus from replicating in the body by inhibiting various viral enzymes. In mid-March, Lopinavir and Ritonavir was approved by the Drug Controller General on an emergency basis to be administered on an infected elderly Italian couple in Jaipur. These are front-line HIV drugs which block Mpro, a key enzyme for coronavirus replication. Also being considered for compassionate use is the antiviral Ebola drug Remdesivir which blocks RNA synthesis, a genetic material of the coronavirus.
Various drugs are being used to control a “cytokine storm,” which is an intense rush of small proteins in response to a virus such as the SARS-CoV-2 when it enters the lungs. Sometimes such self-protective responses from the body’s immune system can turn fatal, killing the patient and need to be controlled by drugs. Tocilizumab, Leronlimab, Sarilumab are reported to enhance the immune response while regulating cytokine storms.
Convalescent plasma and hyperimmune globulin are being looked at as strong contenders, especially in the US. They are derived from the blood of Covid-19 patients who have recovered from the virus. Since they have had a strong immune response to the infection, their blood plasma contains antibodies which can be used to treat others. However, as hopeful it may sound, it is an organisational feat to find donors, extract these therapeutic agents from the blood, and then supply them to either otherwise healthy healthcare workers exposed to high viral loads as a preventive, or to very sick patients who don’t have any other option.
Viruses are inactive on non-living surfaces but the moment they enter living bodies of animals or human beings they become active and pathogenic. Viruses can multiply and complete their life cycle only in living organisms. The SARS-CoV-2 is a single stranded RNA virus which has a protein-based shell with pronounced corona or spikes. Their unique design makes for easy entry and survival in the host. SARS is both severe and acute, and attacks the human respiratory system. But the most troubling part is how rapidly and invisibly it spreads. It can survive on surfaces for several days, waiting for a host to pick it up and accidentally touch their mouth, nose, or eyes.
SARS-CoV-2 has been reported to live for up to three days on hard, shiny surfaces such as utensils, door handles and railings. This is not the case, for example, with HIV, which is also an RNA virus and cannot survive for long in the environment. HIV survives in the fluids like blood and semen only for some hours. When virus-containing fluid leaves the body and is exposed to air, it begins to dry up. As drying occurs, the virus becomes damaged and can become inactive. Once inactive, HIV is “dead” and no longer infectious. Since we are fighting with a more resilient enemy, we need an exact chart on how long SARS-CoV-2 can survive on paper, plastic, fabric, vegetables and cereals - materials that we encounter every day. Most people aren’t aware of sanitising protocols and many lack the resources and protective gear to do so.
Viruses remained an enigma for a long time, an invisible enemy whose effects are often devastating. Several viral diseases such as measles, mumps, rubella, smallpox, chickenpox, polio, hepatitis A and B, rotavirus and haemophilus influenza disease have been controlled. However, no cures have yet been found for HIV, respiratory syncytial virus, the cancer-causing Epstein-Barr virus, Nipah, Lassa and MERS. Vaccines against HIV are still a challenge because HIV divides and mutates so quickly that the antibodies produced by our body become ineffective against newer forms. Antibodies are the defensive proteins produced by the body of a living organism against any foreign matter including viruses.
Many scientists across the globe are working on understanding the structural aspects of the “corona” which is a name for the flared spikes of the virus that latch onto the host cell. If one can hamper its very ability to embed itself in its receptor cell by disarming its spikes, this can help in the development of a vaccination or a cure. According to the International Centre for Genetic Engineering and Biotechnology, New Delhi, the Indian version of SARS-CoV-2 is not as virulent as the one found in Italy due to both its genome sequence as well its corona structure. However, this very difference can also pose a challenge in the development of a universal vaccine.
Vaccine development is going on at breakneck speed. However, it’s unlikely a vaccine can be ready before a year after animal testing and rounds of human trials. Hyderabad-based Bharat Biotech is developing a nasal vaccine called CoroFlu in collaboration with their American counterpart, Flugen, and American virologists. It builds on FluGen’s flu vaccine candidate known as M2SR which is a self-limiting version of the influenza virus that induces an immune response against the flu. The virologists will insert gene sequences from SARS-CoV-2 into M2SR so that the new vaccine will also induce immunity against the novel coronavirus.
American academic labs are using both conventional methods using bits of viral proteins and creative ideas to come up with a vaccine. The University of Pittsburgh is close on the heels of making a durable vaccine patch which consists of hundreds of sugar-protein micro-needles that dissolve into the skin. This high-tech bandaid doesn’t lose potency nor does it need refrigeration.
Many epidemiologists are pinning their hopes on the Bacillus Calmette-Guerin vaccine, widely administered to millions of infants after 1948 as part of India’s universal immunisation programme. It is widely believed that the B.C.G. vaccine, developed to fight tuberculosis, will reduce infections caused by the SARS-CoV-2, and is partly responsible for the reduced number of Covid-19 cases in countries like India and Japan with a history of robust B.C.G. vaccination. Before scientific trials prove its efficacy, officials say one cannot depend on it, advocating quarantine and social-distancing as the only options.
The question is: as infection mounts can the world wait for a year or more before approved drugs and vaccines becomes available? As India enters the third week of the national lockdown, can we protect our most vulnerable groups - our teeming masses on the move to their homes for whom social distancing is an impossible dream, our sick and fragile elderly population, and our security personnel and healthcare professionals?
Assistant Professor
Department of Botany
School of Life Sciences
Central University of Jammu |
