Hyderabad (Telangana): Amit K Maiti, PhD and Director of Genomics and Genomics in the United States said that minimizing ways of transmission and herd immunity are the only two ways to stop the coronavirus.
In an exclusive interview with ETV Bharat Assistant News Editor Verghese P Abraham, Maiti said that SARS-COV2 virus is highly infectious and the protein coat of virus is very strong, thus reducing its possibility of getting destroyed in high temperatures.
Here are excerpts from the interview:
Q1 What is the difference between Covid-19 and other respiratory illnesses like SARS and MERS?
A1: SARS-COV2(Covid-19) has much more infective power than SARS-COV and MERS but there are similarities in their structure and genomes. Survivability of SARS-COV2 is much higher as compared to other viruses. Each virus has two main parts-a protein coat with accessory proteins, such as spikes and nucleic acid as genetic material. As it has high infective power, it means that its protein coat is very strong-not easily destroyed by environmental conditions. Its RNA genome amplification system is very efficient (RDRP-RNA Directed RNA polymerase). Genetically SARS-COV2 (covid-19) is 79% identical with SARS-COV and 52% identical with MERS (1).
Q2 How does this virus enter our body and make us sick?
A2: The virus can enter our body when an individual comes in contact with infected persons or through air-droplets by sneezing or coughing from an infected person. The virus can also be contracted through microdroplet airborne which stays in a closed room for at least 30 minutes.
In most of the cases, virus passes from nose to throat and remains there for a few days (1 to 4) and then passes to lung's alveolar cells. Some of them also travel from mouth to throat but if they reach to the stomach, there is no harm as the enzymes digest the virus. Spike protein of the protein coat of the virus attaches to the cell and binds with the cellular receptor, ACE2 (Angiotensin-converting enzyme II-one of the proteins that regulate blood pressure in human body). The virus injects its RNA genome into the throat and alveolar cell, but protein coat is left behind.
It uses host protein machinery in the cell to amplify (with its RDRP) its genome to millions of copies and also synthesize new coat proteins. The RNA genome is wrapped up with new coat protein and make a full-fledged virus. Then the new virus bursts the lung cells and come to blood and infect other alveoli cells and the entire process is repeated. Some of them reach to heart and brain cells too. As it infects alveolar cells it reduces the power of oxygen exchanging ability of the lungs. In cases when the human body cannot regenerate required number of lung cells, body's regenerative power decreases due to age, diabetes and other health conditions. Old aged people have more probability of getting infected.
Q3 It is speculated that this virus jumped from the animals to humans, how often do we see such mutations that cross-species?
A3: There is no time limit. It can come anytime! But it just not jumps, it takes some time. Actually, a virus which is adapted to live in a non-human host, many of them come in contact with the human but cannot survive in their body. But if they get mutated or finds a common cellular receptor then it acquires the ability to infect human. Most of the mutations are deleterious and not selected to survive. SARS-COV2 has 88% identity with a bat virus (SLCOVZC45) to speculate that it has come from bat. However, as it is not 100% identified it means that it could have come from other unknown viruses too.
Q4 Being an RNA virus, what are the chances of the coronavirus mutating further into other strains?
A4: The study says SARS-COV2 genome is more stable does not have much variations. It indicates that it is selected to infect human and there are also little chances that it can be wiped out from the population by mutation.
Q5 Do climatic conditions have an influence over the spread of this virus?
A5: The protein coat of virus gets destroyed by heat like cooking (100 o C) or in UV rays from bright sunlight. But since the protein coat of SARS-COV2 is much stronger than other viruses, so the possibility of getting destroyed in climatic condition (heat, humidity) is less. The rate of infection is high in Iran, Singapore, Peru, Chile, Ecuador, Israel, Saudi Arabia etc.
Q6 Many people have recovered from Covid-19 but there have been deaths. Are comorbidities the reason making Covid-19 worse in patients having underlying health conditions?
A6: Deaths depends on immunity development and regeneration power of the lung cells of the patient. With old age and health issues like diabetes, re-generation power of the lung cells reduces which makes them more prone to the virus. That is why ventilators are used as it regenerates the cell and maintains the pressure of the cell.
Q7 Is there any truth about males being more susceptible to death due to the novel coronavirus as seen in the cases emanating from Spain?
A7: Yes. Although both the genders are equally but males are dying more than females. Detroit data also reveals the death of men due to coronavirus is more than females but the reason is yet to be known.
Q8 How does this virus affect children? Do they fight the virus better than older adults?
A8: Children are actually carriers of the virus. They get infected but do not develop symptoms (like asymptomatic cases). Children can defeat the virus by developing immunity to it but can infect others.
Q9 Being quite infectious, do you think that minimizing human contacts is the only way to stop this virus?
A9: Minimizing ways of transmissions and herd immunity are the only ways to stop this virus. But people must be careful with food packets, groceries and postal mails. Asymptomatic people are rapidly spreading the virus.
Q10 Do masks actually protect a person from the coronavirus?
A10: Yes. But to avoid transmission by air droplet and microdroplet, one must use masks properly and make sure that eyes. nose and mouth are not touched while wearing it.
Q11 They say a person infected with a contagious pathogen can make it global within 18 hours. Is globalization and ease of global travel to be blamed?
A11: It's true that a person can transmit the virus if they trave across the globe but it's impossible to ban global travel nowadays. If the government would have taken the testing process earlier at the airport, this pandemic could have been avoided. The process of testing started very late.
Q12 What is the concept of herd immunity? Britain opted for this strategy but later dropped it, how does this work?
A12: Herd immunity is resistant to infection by developing immunity. It can be achieved by vaccination and by developing any medicine that helps to build immunity. Britain dropped the idea because they could not find any vaccine or medicine to resist the virus. So, they had to drop the strategy of herd immunity.
Q13 Is there any truth that countries going for universal coverage of BCG vaccine have seen population been given a fighting chance against the virus?
A13: There is no proof that BCG vaccine is effective against COVID-19 (WHO). But some researchers believe that it may be helpful based on the fact that the countries those are least affected like Portugal, Ireland where BCG is acquired during childhood. BCG works in a different manner as it does not raise specific antibodies. It pushes your innate immunity but more research has to be done on the same.
Q14 The demand for anti-malarial drugs have risen and many believe that it could help in the fight against the novel coronavirus. Is chloroquine helpful?
A14: Apparently NOT! In some cases, covid-19 patients are getting cured by hydroxychloroquine or chloroquine but it's discrete. To test antimalarial drugs for a population, proper clinical-set up is required. In two small clinical trials (one in the USA and other in Brazil), it failed with severe side effects. There have been reports of China using it initially but later it was withdrawn due to side effects. Although NIH sponsored large clinical trial is going on, but its outcome is yet to come. So it cannot be confirmed that hydroxychloroquine can be used as a drug to control the virus.
Q15 Initially, there were experiments with retroviral drugs being used to treat Covid -19 patients. Are these drugs effective?
A15: No. Retroviral drugs failed in initial clinical trials, but they are pushing it for large clinical trials as they showed some insignificant benefits. In covid-19, the death rate is 2-12%. We cannot claim that it's effective.
Q16 Vaccines are said to be at least 2 years away, why does it take such a long time for vaccines to be made?
A16: Generally vaccines are antibodies that are developed by introducing the inactive virus as a whole or a part of the key protein, such as spike protein (that are used by the virus to attach the cell membrane).But in later days, vaccines are generally not developed against the whole virus due to disadvantages like large size and inactive virus which may become active in the body, etc. Developing antibodies is not difficult. Even many antibodies of SARS-COV2 are already in the market. But their success depends on how much properly it has been made, how they are delivered into the blood cells, how many doses of protein or DNA can be pushed into a human body. However, excess foreign protein, DNA and MRNA can have some bad effects on the human body.
This decision has to be taken on a population level like giving a vaccine to 5000 people and checking its results. So, these experiments are time-consuming with a lot of precautions. In the next 2 years, the chance of getting a workable vaccine is very less. Even if the patient is recovered, it cannot be confirmed that the medicine is working.
Q17 Does SARS-COV2 infect specific individual or specific group of people?
A17: Yes. Our proposition is that an individual with a particular genotype is susceptible to SARS-COV2 infection. A mutation in IFIH1 gene that is responsible for viral sensing in the body and induces interferon-ß to trigger 1st line of defence acts as immune response which is anti-viral. This mutation carries a model of human IFIH1 gene that are resistant to lethal coronavirus viral attack. If in a population, an individual has C genotype which means CT or TT, that person is more prone to covid-19. Persons with T genotype can resist the virus.
Q18 Once recovered from Covid-19, whether he/she can be infected again?
A18: Yes, it has been observed that in Wuhan, many of recovered patients were tested negative and were tested positive again.
Q19 Will plasma therapy work?
A19: It may work but there are limitations of plasma therapy. Only one person's plasma can be given to one patient. But if the recovered persons did not develop enough antibody it will not have any help. It has other limitations such as any other antigen (HPV, HCV or AIDs) which can be transmitted to other patients.
