COVID-19: Challenges and possibilities of an effective vaccine

Bishaldeep Kakati and Gayatree Hazarika

The global community has been shaken by the pandemic outbreak of a particular Coronavirus disease (COVID-19), which has already led to the death of a huge number of civilians. And the worrying fact is that the number of reported deaths and the number of infected individuals have been simply increasing at a staggering rate. That is the reason, the global population at large is now questioning: When would we witness the discovery of an effective vaccine against this disease?

In fact, at a very short span of time, people at large have already brought into the forum of discussion, the immediate need of an effective vaccine against COVID-19. But the palpable fact is that if till today no effective vaccines could be discovered for diseases like Malaria or HIV, that originated way earlier than COVID-19, then it won’t be a walk in the park in case of  coming out with an effective vaccine against the pandemic COVID-19 as well. Hence in this regard, it is important for the common mass to understand the process of vaccine preparation, and also the challenges to it.

The word “vaccine” originated from the Latin Variolae vaccinae (cowpox), which Edward Jenner demonstrated in 1798 could prevent smallpox in humans. Thereafter in 1885, French chemist Louis Pasteur developed what he called a rabies vaccine, although it was merely a rabies antitoxin that functioned as a post-infection antidote only because of the long incubation period of the rabies germ. However in the modern era, the term vaccine can be defined as all biological preparations made from living organisms to enhance immunity either by treating the disease (therapeutic vaccines) or preventing the same (prophylactic vaccines).

In theory, any infectious disease might be prevented with a vaccine. But in practical terms, the variable nature of the immune response to each specific disease causing organism has meant that the development of vaccines has been limited only to a few viral and bacterial diseases. In fact, even when immune mechanism for specific diseases have been understood, none could still give the guarantee that the same vaccine design could successfully be applied to similar disease agents. That is the reason, the entire process of coming out with an effective vaccine is a complex and time consuming affair.

Furthermore, before a vaccine is licensed, it has to pass through a number of processes. After a vaccine is produced, it is first checked by testing it on animals. If there is no particular harm caused to the animal, then the same vaccine is tried upon a small group of people. And if there is no evidence of harm in human beings, testing proceeds to a large number of people. However, if a safety concern arises at any one phase, it would eventually stop the clinical study from advancing to the next phase.

Moreover, the entire process of vaccine production also faces a number of primary challenges even before the scientists move into the ambit of doing extensive research to discover an effective vaccine against a disease. The very first challenge to the process of vaccine production comprises of adequate funding and concerns regarding safety and contamination. Furthermore, public reactions to a vaccine are also quite strong, since some people view discovery of vaccines as scientific miracles, while others still feel skeptical about the fact that whether or not a particular vaccine could help them recover from a particular kind of disease. It must also be taken into consideration the fact that vaccines are developed and brought to the market by pharmaceutical companies and the major dilemma for the pharmaceutical companies is that demand tends not to coincide with an ability to pay. Added to this, inadequate preclinical data and lack of detailed information on protective correlates of immunity contribute to product failure in clinical trials, which is also a major challenge to the process of vaccine production.

In this context, in case of Covid-19, at least 43 vaccines are in the development stage around the world in places like Brisbane, Hongkong, USA, UK. However, most scientists are not advocating the conventional method of utilizing weakened forms of germ, but are rather focusing on the short copies of parts of the virus’s genetic code i.e., its RNA to produce the vaccine. According to a report given by Anthony Fauci, who is a doctor and head of the US National Institute of Allergy and Infectious Diseases, an American company named Moderna has already started human trials of a possible COVID-19 vaccine in 45 healthy adult individuals. Researchers from around the world have also been concentrating to single out sets of genes that make specific viral proteins such as the S-protein that leads to the formation of the spikes on the virus’s outer envelope, which is a distinct characteristic of the entire coronavirus family, so as to make them act as antigens (weakened form that elicits an immune response in the host). These genes have been synthesized artificially in laboratories by constituting it with the same components that make our DNA, and further the same has been sent for human trials.

Furthermore, Jonathan Heeney, who is a Canadian pathologist has raised certain uncertainties that a possible COVID-19 vaccine might have to face while interacting with human biology. In this regard, Jonathan’s concern cannot be discarded directly since history has many accounts that depict the failure of many vaccines, either because of contamination or specific reactions in human bodies. In 1942, a yellow fever vaccine contaminated with hepatitis B vaccine had taken the lives of almost 150 American troops. The Cutter incident of 1955 in which the Cutter Laboratories failed to properly deactivate the Polio virus, eventually led to 40,000 cases of polio, paralyzing hundreds with the deadly disease. In fact in 1976, in New Jersey, the then President Ford’s plan to vaccinate everyone to protect them from the swine flu, ignoring the warnings coming out of the clinical trials led to around 450 people contracting the Gullain- Barre syndrome(a neurological disorder), out of the 40 million Americans who were vaccinated. Thus history too paints some alarming pictures regarding vaccines adverse reactions on human body.  

Presently, researchers are actually oriented towards coming up with a broad spectrum vaccine that would be effective not just for Covid-19 but also for SARS-CoV and MERS-CoV. Therefore, the emphasis is to design vaccines which would possibly destroy the entire family of a specific virus, so that in near future it would help us win the battle not just for Covid-19 but against all such similar kind of diseases.

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Apr 4, 2020