By: Tali Elias (MS2)

In less than a year since the outbreak of the COVID-19 pandemic, pharmaceutical companies Pfizer and Moderna developed vaccines that promise an impressive 90-95% efficacy in protecting against the virus. Yet, the terrifying reality of receiving a novel vaccine with such limited data has cast a dark shadow over this groundbreaking advancement. Using revolutionary mRNA technology, these vaccines work by delivering genetic information instructing our cells to encode the spike proteins that coat the virus. A remarkably efficient mechanism, this vaccine trains the body’s immune system to mount an attack against the virus upon future exposure, without any exposure to the virus itself.  This method not only makes the vaccine safer than others by avoiding exposure to any live or inactivated forms of the virus, but it has also facilitated the unprecedented speed at which mass quantities of these vaccines were able to be developed under the urgency of the pandemic.

Compared to complex previous technologies that required growing large amounts of a virus and then weakening it by extracting critical components, it is relatively easy to make large amounts of mRNA in a laboratory. Though the mRNA vaccine for COVID-19 is the first of its type to be approved, research into this technology did not begin with COVID-19 and has been under investigation for over 30 years, ultimately yielding the development of a non-infectious, effective vaccine that is easier and quicker to produce. Additionally, while this strain of coronavirus is novel, research on previous coronaviruses such as SARS and MERS gave researchers a jump start in understanding the viral genome and the protein that would become critical in the development of a vaccine. The obvious question then becomes: if the mRNA vaccine is not only not inferior to previous methods, but arguably superior and the technology was at the point where it had overcome the challenges to ensure it could work as intended, why was it not used until this point? The answer is also nothing new. In science, moving forward into unknown territory sometimes requires an even greater threat to come along to give progress the push it needs.

Challenges regarding the scientific integrity of this vaccine, however, were only the first hurdle it had to face, as social media quickly spread the theory that the vaccine might be capable of negatively impacting female fertility. Claiming that there is a similarity between the COVID 19 spike protein produced by the mRNA vaccine and the syncytin-1 protein, a protein necessary for formation and adherence of the uterus to the placenta, proponents of this theory suggested the vaccine could elicit an immune response against the placenta, thereby endangering a woman’s fertility. This theory, however, has been proven wrong on multiple fronts. While sequences for the two proteins share a few of the same amino acids, the proteins are completely different and nowhere near similar enough to elicit cross-reactivity. While some of the legitimate fear surrounding the vaccine and fertility stems from a place of ‘we simply don’t know yet’ due to lack of longitudinal data, what we do know is that women who have had the virus have not displayed any increased difficulties getting pregnant. The vaccine is simply an artificial means of producing an identical protein that the virus would have to produce in order to infect an individual. If one wanted make an argument that the vaccine causes an autoimmune response, enabling the immune system to target the syncytin-1 protein, that would also mean that anyone who had been infected by the virus and was therefore exposed to the virus’ endogenous S-protein should also have had this immune response, an event which simply has not happened. Ultimately, despite the fact that the theory has zero scientific legitimacy, the sentiment that the vaccine may cause female infertility was contagious, leaving many fearful of the vaccine despite scientific proof that should have convinced a person otherwise.

While for some people reservations regarding the vaccine stem from blatant misconceptions, others simply feel uncomfortable about a new vaccine for a virus that has taken so many unexpected turns over the course of a year, transforming the world as we know it and baffling scientists and doctors at the tops of their fields. Those in the latter camp may be further swayed by the belief that the virus has proven less deadly for their respective demographics, and conclude that the minimal risk does not demand a need for a vaccine, especially one that we are only still learning about as increasing numbers of the population are vaccinated. As real-life accounts unfold at a faster rate than the data can be analyzed and understood, new narratives surrounding the vaccine will emerge and the arguments advocating for the vaccine will likely continue to face opposition, whether legitimate or not.

Though it may be optimistic to think these vaccines are a checkmate that gives us a clear endgame for coronavirus, what is clear is that a virus that claimed over 2 million lives in one year cannot be expected to disappear on its own. As the virus continues to spread and mutate, the threat of COVID 19 and its accompanying unknowns will persist, and without the vaccine, there is no hope of stopping it.


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Fertility and Sterility. (2021, January 25). COVID-19 vaccine and infertility: Baseless claims and unfounded social media panic. Retrieved January 28, 2021, from

Fiore, K. (2020, December 03). Want to Know More About mRNA Before Your COVID Jab? Retrieved January 28, 2021, from

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