BACKGROUND OF COVID-19

The origins of COVID-19, or the coronavirus disease, is currently
unknown. Although many theories exist about the origins of
COVID-19 in Asia, there is no concrete evidence to support these
theories. One theory is that COVID-19 arose in the Wuhan
Institute of Virology in China, an institute that analyzes viruses
associated with bats and the genomes of these viruses. This
theory arose due to the fact that the Wuhan Institute of Virology is
located near the live animal Wuhan market in which early cases of
COVID-19 were detected in December. Critics, along with U.S.
President Donald Trump, have speculated that the COVID-19
disease could have been released into the market due to low
biosecurity measures in the institute. However, further
microanalysis of the genome of the COVID-19 virus indicates that
this theory is not plausible as the virus does not have a structure
that seems to have been engineered or built off of a previous, or
existing, virus structure. Although the origins of COVID-19 are
unknown, the virus shows a striking similarity to zoonotic viruses
from bats. After researchers analyzed the genome of the virus in
the Wuhan Institute of Virology, they found that the genome was
very similar to coronaviruses from horseshoe bats. In the past,

such zoonotic diseases have been looked over as many people
believed that these diseases from animals could not harm
humans. However, after zoonotic diseases from bats, such as
SARS and MERS which impacted millions of people across the
world, the world has grown to fear such zoonotic diseases. In the
transmission of coronaviruses, such as COVID-19, an
intermediate animal is necessary if the disease is to pose any
harm to a human. Originally, snakes were thought to be the
intermediate between bats and humans in the transmission of
COVID-19. However, this possibility was ruled out after
researchers found that a strain of coronavirus in pangolins, a type
of anteater, had a 91% similarity to COVID-19, indicating that
pangolins were indeed the intermediate animal for this zoonotic
virus. To address over 5 million cases of COVID-19 worldwide and
over 400,000 deaths, researchers are analyzing how pangolins
are able to remain unaffected as carriers of COVID-19 to engineer
a vaccine for COVID-19.

VACCINE INTRODUCTION

In engineering a COVID-19 vaccine, many considerations need to
be taken into account. To begin with, the safety of the vaccine
needs to be tested. Although animals have been used to test the
safety of potential COVID-19 vaccines, the vaccines have never
succeeded in preventing complete infection. The tested vaccines
have only been partially successful in improving survival. Even
along the lines of improving the survival of the patient, the vaccine

also needs to be tested to ensure that it can prevent reinfection by
lingering remnants or dormant remnants of the original COVID-19
virus. The next consideration when making a vaccine is
considering the mechanism of vaccination. The purpose of a
vaccine is to activate a patient’s immune system to make target
antibodies to fight against the virus at the moment of infection and
memory antibodies to be able to fight against the virus if a
recurrence of the virus occurs. Types of potential vaccines include
live vaccines, which are weaker forms of the virus. Because this
form is weak, the immune system is given time to recognize the
antigens of the virus but is not directly harmed by the introduction
of the virus. This recognition of the antigens can be later used to
fight the stronger, original virus. Another type of vaccine is
inactivated vaccines, which are dead viruses which the patient’s
immune system can use to learn about the antigens and
characteristics of the original virus. Genetically engineered
vaccines utilize RNA and DNA to make S proteins that are used to
activate the immune system of the patient. All of these
considerations are required to make a successful vaccine for
COVID-19.

TYPES OF VACCINES

Although there is no concrete COVID-19 vaccine being distributed
currently, many candidates for the COVID-19 vaccine are being
considered. The first example is the mRNA-1273 vaccine
introduced by Moderna, a health company. This vaccine consists

of a lipid-nanoparticle vector that contains a S-protein whose
purpose is to boost the patient’s immune system. Moderna
conducted a study to test the effectiveness of the mRNA-1273
vaccine by giving 8 candidates the lowest dose (25 mg) and the
middle dose (100 mg). The results showed that neutralizing
antibodies for the coronavirus were generated to the extent of the
antibodies generated when a person recovered from COVID-19.
However, an issue arises with the limited sample size and also the
fact that older people would need a more tailored vaccine as their
immune systems do not respond as well to vaccines. In addition,
another issue that arises with this vaccine is that patients often
developed redness when given more than 100 mg and for certain
patients, the levels of antibodies significantly exceeded those of a
healthy person. Another example of a vaccine is Ad5-nCoV, which
is an adenovirus vector vaccine that also contains the S protein
that was developed in China. Adenovirus vectors indicate that the
vector or virus were first discovered in adenoid tissue. This
vaccine uses the common cold virus to introduce viruses spiked to
cells to trigger the immune system of a patient. The first human
trial of Ad5-nCoV on May 22, 2020 shows that 1 dose of Ad5-
nCoV in a human patient led to the development of killer cells for
the virus and antibodies specific to the COVID-19 within 14 days.
However, one issue with the vaccine is that 75% of the candidates
given a high dosage reported negative side effects within 7 days.
However, this vaccine shows great promise as a potential vaccine
candidate. Another example of a potential vaccine is INO-4800.
Developed by Inovio, this vaccine delivers DNA plasmids to the

cells that work to generate proteins through transcription and
translation that can activate the immune system and produce T-
cells, or killer cells of the virus, to fight off coronavirus. Phase 1
testing of INO-4800 in humans has only recently begun and
results for this vaccine’s success are expected in June 2020.
Another example is LV-SMENP-DC. This vaccine addresses
dendritic cells, which are cells that present antigens and act as an
interface between immune systems. It uses lentiviruses, or a type
of retroviruses, to modify dendritic cells to present COVID-19
antigens to activate the immune system. This leads to the
production of cytotoxic T-lymphocytes which target and kill the
COVID-19 virus. However, an issue with this type of vaccine is
that the safety and efficiency of this vaccine have yet to be tested.
Hence, this prevents its implementation on human patients for
COVID-19. Finally, another potential candidate for vaccine is
pathogen-specific aAPC. This vaccine examines protein domains
of the virus and makes mini lentiviral, or retroviral, genes to
express COVID-19 antigens to activate the immune system. The
safety of this vaccine and the safety of dosages at different times
(0, 14, 28 days) are currently being tested. In terms of a feasible
candidate of a COVID-19 vaccine, a vaccine has recently been
developed in Oxford. Also known as ChAdOxl nCoV-19, this
vaccine is one of the leading vaccines in the world against
COVID-19. This vaccine targets the virus’s spike protein, or
infecting mechanism, which ensures that the disease will not have
the ability to increase its infectivity. However, this vaccine only has
a 50% success rate among its patients. The above information of

potential vaccines and relatively feasible vaccines shows that,
although the world does have its work cut out for it regarding
vaccines for COVID-19, significant progress has been made.

CONCLUSION

COVID-19, originally only seen in Asia, has grown to impact the
entire world. COVID-19 has reached every continent, except for
Antarctica, and has resulted in millions of cases and thousands of
deaths worldwide. Although researchers are piecing together the
story of COVID-19, from its origins, to its intermediates and
methods of transmission, more work is still required to engineer a
successful and feasible vaccine. Potential candidates include
retrovirus technology, viral vector machines, adenovirus vectors,
spike protein removal technology, and various other technologies.
However, the success of these vaccines is yet to increase above a
50% success rate. As a global society, it is our responsibility to
respond to the challenges posed by COVID-19 by ensuring
sanitization, reporting cases to WHO, gathering information about
COVID-19 mitigation, and helping in the dissemination of this
information. Through the work and efforts of researchers and
scientists, the world will hopefully be able to use existing
knowledge and discover new ideas to prevail against COVID-19.