Covid-19: Virus Variants and Vaccines Explained

Source: covid-19

People often say that most of the time, the world works like clockwork: things always happen the way they were meant to. However, if any one person were asked over a year ago what they had imagined their next decade would look like, no one would have an accurate answer on depicting the following months, days or even years. No one would have foreseen the world at a complete standstill, at its wits’ end. No one would call this clockwork. It has been 523 days since COVID-19 was first reported in Wuhan, China. 447 days (as of 8th June 2021) since the very genesis of Malaysia’s MCOs and yet here we are, almost 500 days later, back at square one. 

COVID-19 first breached the shores of Malaysia on the fateful Friday of January the 24th, 2020. Eight Chinese nationals were quarantined in Johor Bahru that day, following contact with an infected person in Singapore. Three of the eight were confirmed to be infected and subsequently transferred to Sungai Buloh Hospital in Selangor. Guidelines were published to deal with any positive cases found in the other states of the country, and all direct flights from Malaysia to China were halted indefinitely. Fast-forward exactly a month later and the first Malaysian victim to the virus was a 41-year-old male returning from a recent trip to Singapore. The rest, of course, is a long list of sequential and consequential events that show how quickly one such virus can travel, almost a viable contender of a wildfire. What is the coronavirus? What makes up this novel organism that has wrecked absolute havoc and altered the lives we once knew?

A brief look into the history & origin of COVID-19: 

Chinese authorities first reported a novel coronavirus outbreak in Wuhan, Hubei Province, China, in late December 2019. Cases of a typical pneumonia started surfacing and were linked to the city’s Huanan Seafood Wholesale Market. The mysterious virus was dubbed the 2019 novel coronavirus. On New Year’s day 2020, the Huanan market was effectively shut down by Wuhan authorities. On January 11 2020, the first fatality of the novel coronavirus was reported: A 61-year-old Chinese man who was a regular at the Huanan Market. The following day, Fudan University scientists shared the genetic sequence of the novel coronavirus with the rest of the world. A day later (January 13), the first international case of the virus was reported in Thailand.

By February, the virus’s ability to be transmitted from human to human had been ascertained by China. Immediately after the revelation, Wuhan was completely closed off from the rest of the world. Soon after, a global health emergency declaration was also announced by WHO. 

On February 11 2020, The International Committee on Taxonomy of Viruses (ICTV) agreed on an official name for the virus: severe acute respiratory syndrome coronavirus two or SARS-CoV-2. The name was chosen due to the virus’s similarity with the coronavirus responsible for the SARS outbreak in 2003. Furthermore, the disease caused by SARS-CoV-2 was also given the official acronym, COVID-19. (CO – Corona, VI – Virus, D- Disease). And finally, on March 11 2020, WHO officially declared COVID-19 a global pandemic. 

Flash forward to the present, 172 million total cases have been reported all over the globe, and more than 3.6 million people have perished because of it. 

Source: coronavirus

Fact Sheet: COVID-19

The COVID-19 virus is part of a family of viruses called Coronaviridae, hence the initial name: Coronavirus. Coronaviruses, typically a rough, spherical shape, their sizes vary with an average diameter of 50 to 140 nanometers. Human coronaviruses infect the epithelial (tissue) cells of the respiratory tract while animal coronaviruses generally infect the tissue of the digestive tract. This would prove that COVID-19 indeed spread through aerosol transmission as it is a classified respiratory disease, infecting the respiratory system of the human body first. Based on present studies, the size of the virus is highly important information as it determines the ways in which we can properly protect ourselves from it by taking proper precautions and such. Countless health officials globally have since agreed that mask-wearing and social-distancing (of about 6-feet) are adequate ways to curb the spread of COVID-19. There have been reported cases of reinfection of COVID-19 but they are extremely rare. The fatality rate of COVID-19 remains higher than influenza and thus, more dangerous. The N95 mask is a largely recommended mask for the public as it is structured to remove at least 95% of all particles with an average diameter of 300 nanometers or less.

Like any virus, the COVID-19 virus functions the same way: entering the tissue of a host, hijacking a respiratory cell and hence, altering it to replicate the virus on multiple other cells, leaving the individual sick and infected. However, what differentiates this virus from other viruses such as the common cold, is the duration and severity of symptoms as well as the aggressively contagious nature of the COVID-19 virus. It is possible for an infected person to spread the virus for about 5 to 14 days before any signs or symptoms occur. If a person is found to be positive with the virus and displays symptoms, they are considered contagious for up to 10 days. The same can be said for asymptomatic victims. Individuals with weakened immune systems and hospitalised diseases can be contagious for up to 20 days or more. In the end, it all boils down to how long the virus manages to survive in a host’s body. The more viable the environment in a body is for the virus to grow and mutate, the longer the contagious period becomes as the individual progresses into more severe stages of the disease.

Since it is not a bacteria, antibiotics do not combat the COVID-19 virus. However, vaccines have been developed to fight against the infection rate in individuals and essentially lessen the blow of the virus on the human body. Think of it as a simplifier of the effects of the virus as opposed to an amplifier.

COVID-19 Variants:

Like how – even amongst a particular race – people can be genetically diverse, the same could also be applied to viruses. For example, different ‘forms’ of the original virus are known as variants or strains that usually arise due to genetic mutations. 

Why do mutations occur in the first place? Are mutations bad?

Mutations are commonly referred to as the raw materials for evolution. The fact of the matter is that this phenomenon has been around since time immemorial. Mutation drives evolution and, together with natural selection, gave birth to Homo Sapiens and millions of other species. Although different types of mutations are possible, one central tenet underlies all: genetic mutations occur randomly. Hence, mutations are nothing ominous or new in themselves. 

How does mutation affect the virus structure?

Whenever a virus replicates within a host cell, there is a chance that the replicating mechanism will make a mistake and introduce an error into the genome, introducing an unwanted change or a genetic mutation. The severity of this mutation depends on the type of mutation and the altered gene. Still, most of the time, the effects are harmless. However, over time, these mutations may accumulate and modify their surface characteristics (surface proteins).

The immune system depends on these surface proteins to identify and fight the virus. Without such ‘markers’, viruses can safely evade detection from the body’s antibodies. 

How quickly a virus mutates is essentially dictated by how widely it is circulated in the population. For every individual infected, there exists a chance for the virus to mutate. Hence higher the number of people infected, the higher the likelihood of a mutation. In reality, there exist thousands of variants for SARS-CoV-2, but only some are of particular concern, these being the aptly named ‘Variants Of Concerns (VOC)’. 

Variants Of Concerns (VOC) in Malaysia

According to Dr Noor Hisham, three variants of concern have been detected in Malaysia; these being the South African variant (B.1.351), the United Kingdom variant (B.1.1.7) and the Indian variant (B.1.167). 

B.1.351 – First discovered in Nelson Mandela Bay, South Africa, in October 2020. The virus is reported to have a faster transmission rate, up to 50% more contagious than original strains. It is suspected to be the main culprit for the resurgence of cases in South Africa during January 2021. It is also alleged to confer some resistance against current vaccines.

B.1.1.7 – Originally from the United Kingdom, this strain was first detected in December 2020. It has since spread globally and is now the most dominant variant of SARS-CoV-2 in the United States. Research has attributed it to being 50% more contagious and having a higher mortality rate – up to 60% higher than prior widely circulating strains. 

B.1.167 – The main driver for India’s devastating second wave; this Indian strain was first detected in Maharashtra in October 2020. Although the information is still emerging, it is known to be an extremely contagious strain. The UK’s NHS estimates its transmission rate to be equal to or even surpasses that of the UK variant. However, it is still unclear whether it is more severe than the original virus. 

Source:  vaccines

COVID-19 Vaccines: 

For a virus to enter the host cells, viruses require the aid of protrusions on their surfaces known as spike (S) proteins. Thus, if these spikes were somehow neutralised, it would effectively ward off access into the human body. And this is precisely what most vaccines seek to accomplish.

Three of the most popular COVID-19 vaccines currently include the Pfizer BioNTech mRNA vaccine, the Moderna mRNA vaccine and the AstraZeneca adenovirus vaccine.

What are the mRNA vaccines, and how do they work?

Both Pfizer BioNTech and Moderna constitute a new type of vaccine known as the nucleoside-modified messenger RNA (mRNA) vaccines.

Typically, to trigger an immune response in our body, vaccines would use an altered or harmless form of the original virus. However, in the case of mRNA vaccines, it possesses no such thing; it instead houses the virus’s genetic code in a molecule known as mRNA. mRNA (messenger RNA), similar to DNA, carries the instructions needed by an organism to synthesise proteins.

Once the mRNA is inserted into the body (host), it will hijack the host immune cells to read the instructions in the mRNA and synthesise the distinct spike proteins of SARS-CoV-2. Afterwhich, The immune cell will then ‘wear’ and display the spike proteins on its surface. As part of a normal immune response, the immune system will detect the unusual surface proteins and recognise them as foreign to the body. In response, the immune system will start building an immune response by producing specialised antibodies, similar to what would have happened if the body got infected with Covid-19 naturally. 

Within a few days, the mRNA will be degraded by the body, but the specific antibodies will remain, constantly prowling the body for any signs of SARS-CoV-2. The main benefit is that the body now has some knowledge and preparation against the actual virus, should it encounter it. Instead of searching for a mysterious killer, the immune cells now have a wanted poster to go by.

What about the AstraZeneca vaccine?

The AstraZeneca vaccine does not use mRNA technology but instead a chimpanzee-derived adenovirus vector (carrier). The adenovirus is a harmless virus that is often used as vectors in vaccines. The adenovirus is genetically altered to pose no danger to humans. Within the vector is a part of the genetic sequence of SARS-CoV-2 that is responsible for producing the spike protein. Once the vector reaches the nucleus, it will create an mRNA strand to synthesise the spike proteins. The body will then develop immunity in the same way as the case for the other vaccines. 

Present Day

Currently, the world is still reeling from the very seeds of fear this pandemic has sown in the hearts of the public. Sure, society has made progress in terms of developing vaccines and guidelines for the prevention of the infection rate among individuals but it should be clear that this biological warfare is far from over. For the next decade or so, the world will forever need to remain cautious and keep up with the latest ways to secure immunity against this disease. Hopefully through mass immunisation, herd immunity will be developed and the burden of combating this virus will be lighter on the shoulders of frontliners, and health officials. Does the current prerogative society still hold? Hence, everyone should be vaccinated where possible, with whichever vaccine that is available, remain informed on developments regarding the virus and continue practicing and adhering to all guidelines regarding social gatherings, quarantining and all things virus-related. One should not take this virus lightly as it has cost the lives of many and the livelihoods of many more. The sooner every member of society realizes their duty and responsibility to uphold these regulations seriously, the closer we are to finally regaining the stability we once had pre-covid. 

Sources:

Coronavirus (COVID-19) frequently asked questions

The Size of SARS-CoV-2 and its Implications (news-medical.net)

COVID-19: Myths and facts

Coronavirus disease (COVID-19)

Covid-19’s Death Toll Compared to Other Things that Kill Us

By: Hannah Rahel & Yun Jing

Edited by: Maki

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