CORONAVIRUS, THE TWO TYPES, TREATMENTS, AND POSSIBLE CURES
Before we go to the treatments, let me first explain what is the difference between SARS-CoV-2 and COVID-19.
According to LOINC, SARS-CoV-2 is the name of the virus that causes the COVID-19 disease. COVID-19 stands for Coronavirus Disease 2019. The LOINC Component represents the analyte being tested for, which is why the Components include “SARS Coronavirus 2” rather than “COVID-19”.
- SARS-related coronavirus (SARS-related CoV) is a species of coronavirus in the sub-genus called Sarbecovirus. SARS-related CoV includes SARS coronavirus (SARS-CoV), SARS coronavirus 2 (SARS-CoV-2), and bat SARS coronaviruses.
- SARS-CoV is the specific virus responsible for Severe Acute Respiratory Syndrome, which was identified in 2003.
- SARS-CoV-2 is the virus responsible for COVID-19. It was previously known as 2019 Novel coronavirus (2019-nCov).
- Our current understanding of “SARS-like coronavirus” (SARS-like CoV) is that it is a group of viruses that are genetically similar to SARS-CoV but that the group does not include SARS-CoV or SARS-CoV-2. In other words, SARS-related CoV = SARS-CoV + SARS-CoV-2 + SARS-like CoV.
Another similar disease, that is a viral respiratory disease caused by the novel coronavirus (Middle East respiratory syndrome coronavirus, or MERS‐CoV) that was first identified in Saudi Arabia in 2012. Coronaviruses are a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS).
Typical MERS symptoms include fever, cough and shortness of breath. Pneumonia is common, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported. Some laboratory-confirmed cases of MERS-CoV infection are reported as asymptomatic, meaning that they do not have any clinical symptoms, yet they are positive for MERS-CoV infection following a laboratory test. Most of these asymptomatic cases have been detected following aggressive contact tracing of a laboratory-confirmed case. Approximately 35% of reported patients with MERS-CoV infection have died.
Although most of human cases of MERS-CoV infections have been attributed to human-to-human infections in health care settings, current scientific evidence suggests that dromedary camels are a major reservoir host for MERS-CoV and an animal source of MERS infection in humans. However, the exact role of dromedaries in transmission of the virus and the exact route(s) of transmission are unknown.
According to WHO, the virus does not seem to pass easily from person to person unless there is close contact, such as occurs when providing unprotected care to a patient. Health care associated outbreaks have occurred in several countries, with the largest outbreaks seen in Saudi Arabia, United Arab Emirates, and the Republic of Korea.
So what are the differences between the two?
The severe acute respiratory syndrome outbreak in 2002 and 2003 led to more than 8,000 infections worldwide and killed close to 10% of those infected.
It was caused by a coronavirus that made a species jump from bats to humans through the intermediate host of farmed civet cats bred for human consumption in China. From recognition of the outbreak to identification of the agent and animal reservoir, to containment and resolution, the outbreak occurred during a 9-month period.
According to Healio, SarsCov originated from bats, that then spread to humans. The discovery of civet cats as an infection source of SARS for humans occurred about 4 months after the international recognition that there was an outbreak of a new disease. In contrast, it was not until 10 months after the recognition of MERS that camels were suspected as the possible intermediate host.
Between the two, SarsCov spreads much more faster than MERSCov. SARS had a 10% death rate but spreads faster with 8,000 cases worldwide in a span of 18 months, while MERS had an astounding 40% death rate, it spreads slower and only 200 confirmed cases were confirmed in the 18 month period (2002-2003).
SARS were primarily seen in young people, while older people showed symptoms of MERS. Specifically, MERS was seen in people who are 50 years old above. More than 70% severe cases and deaths were listed. While SARS on the other hand, affected male and female equally.
TREATMENTS AND POSSIBLE CURES
-REMDESIVIR
It is an experimental antiviral made by a biotech firm called Gilead Sciences, and it has garnered the attention in today’s pandemic. This has been the most used treatment to severe and critical cases of SARS-CoV-2. This drug has been used in US, China, and Italy.
Remdesivir isn’t specifically designed to destroy SARS-CoV-2. Instead, it works by knocking out a specific piece of machinery in the virus, known as "RNA polymerase," which many viruses use to replicate. Its effectiveness is still being debated, and much more rigorous study will be needed before this becomes a general treatment for SARS-CoV-2, if it does at all.
-FAVIPAVIR
This is the drug used in Wuhan and Shenzhen by Chinese scientists. On March 18, the patients of the Japanese Inlfuenza drug (it was originally made for Japanese Influenza) claimed that the drug managed to shorten the course of the disease, with patients who were given the treatment clearing the virus after just four days, while the others took 11 days to be cleared off.
The drug is manufactured by Fujifilm Toyama Chemical, but the company has declined to comment on the claims. Favipiravir, also known as Avigan, is an antiviral and is designed to target RNA viruses which include coronaviruses and influenza viruses. The drug is thought to disrupt a pathway which helps these viruses to replicate inside cells. According to the Guardian, a source within the Japanese health ministry suggests the drug is not effective in patients showing severe symptoms.
The first COVID-19 patient diagnosed in the United States—a young man in Snohomish County, Washington—was given remdesivir when his condition worsened; he improved the next day, according to a case report in the New England Journal of Medicine (NEJM). A Californian patient who received remdesivir—and who doctors thought might not survive—recovered as well.
In short, Remdesivir is ideal to those who had severe and critical cases of SARS while Favipavir are for those who have mild cases.
OTHER TREATMENTS:
-CHLOROQUINE
This drug had been used to treat malaria for around 70 years and became a potential candidate as treatment for SARSCoV-2. It is stated that chloroquine is abled to block viruses from binding to human cells and getting inside them to replicate. It also stimulates the immune system. A letter to the editor in journal Nature on Feb. 4 showed chloroquine was effective in combating SARS-CoV-2. A Chinese study originating from Guangdong reports chloroquine improved patient outcomes and "might improve the success rate of treatment" and "shorten hospital stay."
According to the journal Nature on March 18, they suggested that hydroxychloroquine, which is a less toxic derivative of the drug, is effective at inhibiting SARS-CoV-2 infection.
-RITONAVIR/ LOPINAVIR
According to ScienceMag,org, this combination drug, sold under the brand name Kaletra, was approved in the US in 2000 to treat HIV infections. Abbott Laboratories developed lopinavir specifically to inhibit the protease of HIV, an important enzyme that cleaves a long protein chain into peptides during the assembly of new viruses. Because lopinavir is quickly broken down in the human body by our own proteases, it is given with low levels of ritonavir, another protease inhibitor, that lets lopinavir persist longer.
The combination can inhibit the protease of other viruses as well, specifically coronaviruses. It has shown efficacy in marmosets infected with the MERS virus, and has also been tested in SARS and MERS patients, though results from those trials are ambiguous.
The first trial with COVD-19 was not encouraging, however. Doctors in Wuhan, China, gave 199 patients two pills of lopinavir/ritonavir twice a day plus standard care, or standard care alone. There was no significant difference between the groups, they reported in NEJM on 15 March. But the authors caution that patients were very ill—more than a fifth of them died—and so the treatment may have been given too late to help. While the drug is generally safe it may interact with drugs usually given to severely ill patients, and doctors have warned it could cause significant liver damage.
Keep safe everyone.
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