COVID-19 Pharmaceuticals

The Implications of Pfizer’s New Antiviral COVID-19 Pill, Paxlovid

Donna Mahboubi—McMaster Health Sciences 2026

Chances are you’ve heard mentions of a COVID-19 pill, but you may be wondering, “What actually is it?” There are many emerging treatments for COVID-19 meant for people who are already infected with the virus, including treatments taken orally. These treatments differ from vaccinations because they actively treat the virus whereas vaccines are used as a preventative measure to avoid getting infected in the first place. Similarly to the COVID-19 vaccines, however, Pfizer is one of the first to hop onto the COVID-19 pill train, having created the first FDA-approved oral treatment for COVID-19, Paxlovid (1).

What exactly is Paxlovid?

Paxlovid is the combination of two nirmatrelvir pills and one ritonavir pill, all taken twice a day over the span of five days (2). Nirmatrelvir, a drug created by Pfizer, is the drug in Paxlovid that contains Paxlovid’s antiviral properties, limiting the replication of the virus (2). Ritonavir, an existing drug typically used in the treatment of HIV/AIDS among other things, allows nirmatrelvir to remain in the body at higher concentrations for longer periods of time; it does this by being a CYP, cytochrome P450, inhibitor (3). CYPs are enzymes that are involved in the termination of many drugs, including nirmatrelvir, so inhibiting them enhances and prolongs the antiviral properties of nirmatrelvir. It is recommended that Paxlovid is taken within five days of symptom onset (1).



Nirmatrelvir and ritonavir clearly work together to create a powerhouse of a COVID-19 treatment that demonstrates immense benefits. A nearly five-month-long clinical trial conducted by Pfizer, which concluded in December 2021, showed an 89% decrease in severe illness and death when the drug was taken within three days of symptom onset as compared to a placebo (4). This trial, called EPIC-HR was done on adults who present a high risk of COVID-19 progressing to a severe illness. In the same trial, 0.7% of patients who received Paxlovid were hospitalized as opposed to 6.5% who received the placebo being hospitalized or dying (4). In a second trial, EPIC-SR, done on adults at a more standard risk, hospitalization was reduced by 70% as compared to the placebo (4).

However, Paxlovid is not perfect. It’s not recommended for certain populations such as those with severe kidney or liver impairments (1). A lack of research also makes it difficult to prescribe to certain populations such as people under 40 kilograms, pregnant or lactating people, and those on drugs that could have potentially dangerous interactions with Paxlovid (5).

Implications and the Future

Paxlovid has not only paved the way for other COVID-19 antiviral pills, but also for other forms of COVID-19 treatments. These include antiviral-type treatments, such as the oral treatments Paxlovid and Molnupiravir, and the intravenous treatment Remdesivir (6). Monoclonal antibodies are another form of COVID-19 treatment that improve the immune system’s response to the virus as opposed to targeting the actual virus itself. Bebtelovimab is a monoclonal antibody that combats COVID-19 through intravenous injection (6). Paxlovid is just the beginning, and the creation of new COVID-19 treatments can improve the accessibility of a treatment for those who can not take Paxlovid for a multitude of reasons or in situations where Paxlovid is not available.


The accessibility of Paxlovid has actually been a large issue. This is in part due to the lack of transparency that producers of Paxlovid have demonstrated, particularly in the realm of costs and remaining supply. The lack of transparency has led to challenges in lower-income countries receiving the treatments, resulting in the WHO declaring its concerns regarding Paxlovid accessibility (5). The COVID-19 pandemic has already led to great global divides, and Paxlovid’s limited accessibility gives it the potential to further increase disparities within global health.

Although the future of COVID-19 treatments and the potentially negative implications of Paxlovid are greatly unknown, its introduction into the world of healthcare is quite beneficial and exciting. Paxlovid has opened up a new realm of research within the topic of COVID-19 and has provided an amazing opportunity for collaboration to lead to many incredible discoveries!


  1. Louisiana Department of Health. FDA authorizes first antiviral pills for COVID-19 [Internet]. [cited 2022 Nov 28]. Available from:
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  1. NIH. Paxlovid Drug-Drug Interactions | COVID-19 Treatment Guidelines [Internet]. [cited 2022 Nov 28]. Available from:–paxlovid-/paxlovid-drug-drug-interactions/
  1. Pfizer. Pfizer Announces Additional Phase 2/3 Study Results Confirming Robust Efficacy of Novel COVID-19 Oral Antiviral Treatment Candidate in Reducing Risk of Hospitalization or Death [Internet]. [cited 2022 Nov 28]. Available from:
  1. Jerving S. WHO recommends Pfizer’s COVID-19 pill, but poor nations may lack access [Internet]. Devex. 2022 [cited 2022 Nov 28]. Available from:
  1. CDC. COVID-19 and Your Health [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2022 Nov 28]. Available from:
  1. CBC News. How do I get the COVID-19 medication Paxlovid? | CBC News [Internet]. CBC. 2022 [cited 2023 Jan 11]. Available from:
  1. CDC. COVID-19 and Your Health [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2023 Jan 11]. Available from:
COVID-19 Sleep

Chronic Fatigue Syndrome in the Time of COVID-19: Understanding the Connection

Bhavana Soma—McMaster Life Sciences 2024

Imagine constantly feeling tired to the point where it is difficult to perform daily activities, having no amount of rest make you feel energized, having difficulty sleeping, taking a long time to recover after physical activity, and having issues with thinking, concentrating and remembering. This miserable slew of symptoms that deeply affect the quality of one’s life is characteristic of a debilitating condition known as chronic fatigue syndrome (CFS). Presentation of these symptoms, in addition to physiological symptoms including heart palpitations, general malaise, flu-like symptoms and body pains, over an extended period of time can lead to a diagnosis of CFS if not thoroughly explained by underlying medical conditions [1]. This complicated disorder affects anywhere between 836 000 to 2.5 million Americans, and millions more worldwide [2].

SOURCE: Medical News Today

Scientists have identified a similar condition in those that have contracted COVID-19. COVID-19 starts with a respiratory infection that produces common flu-like symptoms. However, it can have extensive systemic effects on the body as the virus attacks cells and disrupts bodily functions. This means that it may eventually affect the heart, blood vessels, brain, liver, eyes, and kidneys in the long term, in addition to the respiratory system and immune system [3]. The long-term effects become apparent when the test that initially detected the virus is no longer able to, which implies that affected individuals should return to normal since the virus is no longer present in their bodies [4]. However, COVID-19 research has demonstrated that this is not always the case.

Ongoing research suggests that up to a year after having COVID-19, 20% of adults have at least one medical condition that may be a result of the viral infection. This increases to 25% for seniors above the age of 64 [5]. The development of new conditions may be attributed to damage to different organ systems throughout the body and the experience of severe COVID-19, resulting in hospitalization, could trigger mental health conditions [5]. Not only have individuals been diagnosed with new conditions after supposedly having recovered from COVID-19 within a few weeks, many have been experiencing long-term symptoms including, but not limited to, fatigue, difficulty thinking, remembering or concentrating, cognitive difficulties, sleep disturbances, shortness of breath, increased instance of mental health issues, and body pains [6]. These ongoing symptoms are collectively being referred to as a condition called “Long COVID [4].”


With the significant overlap between the symptoms of Long COVID and CFS, and the fact that the onset of both Long COVID and up to 75% of CFS cases are confirmed to be linked to a viral infection, many researchers have begun to wonder if the two conditions are actually the same the condition [7].

As of present, there is no cure for either condition. The treatment of CFS is mainly concerned with searching for underlying causes and treating any that are found, as well as alleviating symptoms. Doctors attempt to address the most debilitating symptom prior to treating others that are present [8].

As for Long COVID, researchers all over the world are currently conducting studies and trials to learn more about the condition. In one recent study, people who had been infected with the virus prior to vaccination had a 9 percent lower risk of developing Long COVID after receiving two doses of an mRNA or adenoviral vector vaccine. According to many researchers, we can learn more about the disease and how to better treat it by looking at in-depth analyses of markers such as autoantibodies that are associated with the disease. Current trials that are being conducted include anti-inflammatory drugs, and future potential research could be conducted on immune-suppressing drugs [9].

Since the overlap between Long COVID and CFS has been identified and the question of Long COVID being a form of CFS has been raised, influential CFS researchers believe that the similarities between the two could help millions manage their condition. Their research has shown how CFS may develop due to an overactive immune response in the early stages of the disease that results in immune exhaustion which is also found in chronic viral infections. Future research suggestions include examining biological markers of those who successfully made a full recovery from COVID-19 to better understand the mechanisms that result in a full recovery [7].


  1. Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) [Internet]. NHS. NHS; 2021 [cited 2022 Nov 28]. Available from:
  2. Institute of Medicine, Board on the Health of Select Populations, Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Beyond myalgic encephalomyelitis/chronic fatigue syndrome: Redefining an illness. Washington, District of Columbia: The National Academies Press; 2015. 
  3. How COVID-19 affects your body in pictures [Internet]. WebMD. WebMD; 2020 [cited 2022 Nov 28]. Available from:
  4. Komaroff AL, Bateman L. Will COVID-19 lead to myalgic encephalomyelitis/chronic fatigue syndrome? Frontiers in Medicine. 2021;7. 
  5. Mayo Clinic Staff. Covid-19: Long-term effects [Internet]. Mayo Clinic. Mayo Foundation for Medical Education and Research; 2022 [cited 2022 Nov 28]. Available from:
  6. Public Health Agency of Canada. Government of Canada [Internet]. Post-COVID-19 condition (long COVID) – / Gouvernement du Canada; 2022 [cited 2022 Nov 28]. Available from:
  7. Is long covid really chronic fatigue syndrome by another name? [Internet]. Columbia University Mailman School of Public Health. Columbia University Irving Medical Center; 2021 [cited 2022 Nov 28]. Available from:
  8. Chronic fatigue syndrome [Internet]. Mayo Clinic. Mayo Foundation for Medical Education and Research; 2022 [cited 2022 Nov 28]. Available from:
  9. Ledford H. Long-Covid Treatments: Why the world is still waiting [Internet]. Nature News. Nature Publishing Group; 2022 [cited 2022 Nov 28]. Available from:
COVID-19 Pharmaceuticals

The Future of Vaccine Companies: Unceasing Competition

Seonhwa Lee—McMaster Honours Human Behaviour 2024

With decreasing trend in infection cases and lighter restrictions following the expedite development of effective vaccine supply, it seemed like the world was finally coming back to normal. This hope is now shattered with the recent emergence of omicron, the new variant of COVID virus. At this time of inflection, what is the future of major vaccine companies?

Engaging Variant and Booster Vaccines

Omicron varies from other COVID viruses in its numerous mutations in the spike protein, which the vaccine aims to mimic to produce antibodies. In fact, studies were conducted by Pfizer and BioNTech to see a significant decrease in the number of virus-targeting antibodies in omicron (1). They also found evidence to support the efficacy and efficiency of booster shots in increasing the production of antibodies as well (1). Booster shot is injected after an individual has received one or two previous doses of regular vaccine against COVID depending on the type.

SOURCE: The Sudbury Star

The Canadian government had authorized companies producing viral vector-based vaccines such as Janssen and AstraZeneca for adults over 18 years of age, and mRNA vaccines such as Moderna and Pfizer and BioNTech (2-5). mRNA vaccines were given full approval to give children over 5 (Pfizer-BioNTech) and 12 (Moderna) with reduced dose, and Spikevax by Moderna was especially approved as a booster shot in November (4-6). Pfizer and BioNTech is also planning to drop their new vaccine adjusted to target omicron in March 2022 depending on the need, as well as 4 billion more of their current Comirnaty vaccine supply (1).

Antiviral Pills

 Aside from vaccines, companies are also striving to develop pills to cure. Pfizer is in the lead among major companies with their two-pill antiviral named Paxlovid, which showed outstanding efficacy by dropping hospitalization and death by 89% (1). Paxlovid is used to treat relatively mild symptoms in unvaccinated individuals and the above-mentioned result was when patients took the pill within three days of symptoms (1).

Merck also dropped a one-pill antiviral called Molnupiravir less impact than Paxlovid by reducing hospitalization and death by 30% when taken within five days after symptoms first appeared but is still clearly in lead compared to other companies (1).

Progress on making the most effective vaccine or cure is a key factor in the inevitable competition among these pharmaceutical companies.

Side Effects and Post-Pandemic

Despite the fact that all types of vaccine currently used by countries are authorized and approved for its “safety”, current vaccines are suspected of possible side effects spanning from light redness and swelling to serious hear inflammation (7).

SOURCE: Today Show

Once confirmed cases decrease again and the pandemic gets closer to the end, the corporates will likely have a decreased stock value and maybe change the price to directly target the public with COVID products remaining on the market and focusing more on regular products they had before the virus; if they are still authorized despite the side effects with no immediate threat.


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  2. Canada H. Government of Canada [Internet]. / Gouvernement du Canada; 2021 [cited 2021Dec11]. Available from:
  3. Canada H. Government of Canada [Internet]. / Gouvernement du Canada; 2021 [cited 2021Dec11]. Available from:
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  5. Canada H. Government of Canada [Internet]. Pfizer-BioNTech Comirnaty COVID-19 vaccine – / Gouvernement du Canada; 2021 [cited 2021Dec11]. Available from:
  6. Canada H. Health Canada authorizes the use of the Moderna Spikevax COVID-19 vaccine as a booster shot [Internet]. Government of Canada; 2021 [cited 2021Dec11]. Available from:
  7. Gatlin A. Is moderna stock a buy or sell as shares Yo-Yo on the omicron threat? [Internet]. Investor’s Business Daily. 2021 [cited 2021Dec11]. Available from:

mRNA Vaccines and the Future of Vaccination

Rodrigo Hontoria — McMaster University Honours Life Sciences 2023

Over the past 3 decades, scientists have been working with messenger RNA (mRNA) as a potential new method of producing simpler and more effective vaccines1 2. mRNA is a promising topic to assess because of its ability to produce a vast number of proteins, all depending on the coding of each mRNA. In a cell, mRNA is transcribed from DNA and undergoes a series of modifications that provide protection from the cellular environment, before finally being released into the cytoplasm for translation. Incorporating mRNA into modern vaccinations would provide three very beneficial outcomes:

  1. Safety – unlike other vaccines that require a weakened/damaged strain of the virus, mRNA vaccines provide a non-infectious route to immunity1 2. Also, after translation has occurred, mRNA is quickly degraded by the cell avoiding any long-lasting effects1.
  1. Efficacy – mRNA vaccines provide a highly detailed method for producing an immune response by inducing the production of whichever desired viral protein. In other words, mRNA strands can be made to encode the exact viral protein, without any of the deleterious and self-replicating genes of the virus. The lifespan/stability of mRNA can also be adjusted through changes in its 5’ cap and poly-A tail, or carrier molecule to change the time span of its desired effects2.
  1. Cost of production – Synthetic viral mRNAs are significantly less costly to produce compared to the manufacturing of proteins and viral antigens1.
A diagram of an mRNA vaccine in action. It shows a synthetic mRNA being translated by a ribosome into individual proteins from SARS-CoV-2, which induce an immune response.
Source: The Conversation

Setbacks and Advancements

In 1990, a group of scientists performed the first successful mRNA injection using reporter genes to induce the production of the corresponding proteins in mice1. In follow up experiments, physiological effects were observed in mice after the uptake of synthetic mRNA that stimulates the release of different hormones1 2. Although these early successes were very exciting and provided a potentially prosperous technology, many advancements in research were still necessary to achieve safety and efficiency. mRNA vaccine setbacks have been outlined thoroughly in past research projects, some of the most notable being: 

  1. Passage of mRNA from the bloodstream into the cell – through vaccination, mRNA will directly enter the bloodstream but how will cells be encouraged to uptake the mRNA?
  1. Stability/protection of mRNA when inside the cell – how will the mRNA be protected to avoid mutagenesis or breakdown?

To overcome these problems, companies such as Pfizer, BioNTech, and Moderna invested a lot of time, money, and effort into making mRNA vaccines effective. To facilitate transport of mRNA into the cell, common transfection reagents such as cationic lipids, calcium phosphate, and cationic polymer liposomes are used3 4. mRNA stability was achieved with the addition of untranslated regions (UTRs) added to the 5’ and 3’1 3

COVID-19 and Future Applications

On January 9, 2020, the Global Health Organization along with Chinese Health Authorities identified the novel coronavirus as 2019-nCoV (COVID-19)6. 2 days later, the Chinese government globally released the genomic sequence of the virus6. Pfizer, BioNTech, and Moderna were quick to start working on the vaccine. Only 11 months after COVID-19 was identified, the United States and United Kingdom established the latest mRNA vaccines as safe and effective1

Pfizer-BioNTech and Moderna mRNA vaccines code for a spike protein found on the membrane of the virus. Cellular uptake of the mRNA induces the production of a spike protein inside the host cell. The spike protein by itself is harmless and non-infectious but nonetheless, causes an immunological response that is remembered by the immune system. Pfizer-BioNTech and Moderna both require two doses of the vaccine, Pfizer-BioNTech requiring 21 days of separation, and Moderna requiring 28 days. Pfizer-BioNTech has a high effectiveness rate of 95% while Moderna is slightly lower at 94.1%.

Further applications for mRNA vaccines are contributing to the treatment of many more viral agents, among these are Ebola, Zika and Influenza. Cancer treatments, and genetic therapies are also looking at mRNA vaccines as a potential treatment to produce proteins that the body requires. 

Image result for covid 19 vaccines
Source: Aljazeera


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A Closer Look at the Janssen Vaccine: How Effective is it?

Madison Norris — McMaster University Honours Life Sciences 2023

Over the last two years, the COVID-19 pandemic has completely changed the way in which we go about our everyday lives. The shift to online classes, working from home, social distancing restrictions and stay at home orders have left many yearning for a sense of normalcy. The only feasible solution to see us through the pandemic is the mass vaccination of the majority of the population.

Johnson and Johnson recently announced the completion of phase 3 clinical trials of the single dose Janssen vaccine. The Janssen vaccine contains viral DNA within a modified adenovirus that codes for the spike protein found on the surface of the SARS-CoV-2 virus. (1) Adenovirus-based vaccines use adenoviruses as vessels that will release genetic material upon entry into the cells of an inoculated host. The purpose of the vaccine is to protect against moderate to severe COVID-19 infections, including emerging variants of the virus, such as the B.1.351 variant proliferating in South Africa. (2)

In phase 3 clinical trials, 43,783 participants, 18 years of age or older, participated in a randomized double-blind study that compared the safety and efficacy of the Janssen vaccine to a placebo control. (2) The study population represented 8 different countries, including the United States, countries in Central and South America and South Africa. The study also included participants with comorbid conditions, such as obesity, type 2 diabetes, hypertension and immunocompromising conditions. (2) 28 days following vaccination, the Janssen vaccine demonstrated 66% efficacy. (2) However, it is important to note that differences in efficacy were found across geographical regions. The vaccine was observed to be most effective in the United States (72%) and less effective in Latin America (66%) and South Africa (57%). (2) In addition, the Jassen vaccine demonstrated similar rates of efficacy across age groups, including adults over the age of 60. The only side effect observed was a fever in approximately 9% of participants. As of March 5th, Health Canada has approved the Janssen vaccine.            

A notable difference between the Janssen vaccine and other competitor vaccines (Moderna and Pfizer) is that it can be stored for longer periods of time at refrigerator temperatures. To illustrate, the Janssen vaccine can be stored at 2°C to 8°C for 3 months, whereas the Moderna vaccine can only be stored at these temperatures for 30 days (3/4). Moreover, the Pfizer vaccine cannot be stored at refrigerator temperatures at all, and must remain in -60°C to -80°C conditions. (4) The ability to store the Janssen vaccine for longer periods of time at refrigerator temperatures presents the opportunity to transport vaccines to remote locations.

Another distinction of the Janssen vaccine is that while it has been observed to be less effective (66%) it only requires one dose. In contrast, both Moderna and Pfizer require two doses but are remarkably more effective at 94.1% and 95% efficacies, respectively. (5,6) This offers a potential solution to countries financially unable to fully vaccinate their citizens with a two dose vaccine. A more feasible alternative could be to vaccinate the elderly and at-risk populations with either the Pfizer or Moderna vaccines, as they are more susceptible and will experience more severe symptoms of the virus. The remaining population could then be vaccinated with the Janssen vaccine, as they have stronger immune systems that will allow for greater rates of recovery. (7)

In sum, the Janssen vaccine demonstrated an overall efficacy of 66%. The vaccine offers solutions to transportation, storage and financial barriers to vaccination. Following FDA approval, the administration of the Janssen vaccine brings the global population closer to herd immunity and one step closer to returning to normal life.


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  1. CBC News. Johnson & Johnson single-shot COVID-19 vaccine appears 66% effective overall in global trial. The Associated Predd [internet]. 2021 Jan 29 [cited 2021 Feb 24]; Health: [about 1 p.]. Available from: