In addition to many other changes felt profoundly as a result of the COVID-19 pandemic, vaccines have assuredly become a hot topic of discussion. Over the last nine months or so, worldwide, people began exploring and researching vaccine production and distribution, ingredients, side effects, and effectiveness. The more generic conversation about vaccines was then escalated as three different COVID-19 vaccines received an emergency use authorization from the U.S. Food & Drug Administration. Specifically, “Pfizer’s vaccine was authorized Dec. 12, 2020; Moderna’s version received authorization Dec. 18, 2020; and Johnson & Johnson’s was authorized Feb. 27, 20211.” The introduction of three separate vaccines by three separate pharmaceutical companies brought to the forefront the following burning questions: what is the real difference in the vaccines and which vaccine is the “right” vaccine to get?
Generally speaking, vaccines help people develop immunity to a virus or other germ by introducing a less harmful part of that germ, or something created to look or act like it, into a person’s body, to create an immune response that ideally keeps the person from getting sick1. As there is so much unknown about COVID-19 or coronavirus and the impact of it has been so widespread and pervasive, it’s understandable that folks had some questions or concerns. A source of greater confusion is the Johnson & Johnson (“J&J”) vaccine, as it is marketed as a one dose vaccine, unlike the Moderna and Pfizer vaccine, which are both characterized as two-dose vaccinations.
Let’s start with what we know about the J&J vaccine. First of all, you might also see the vaccine referred to as the Janssen Pharmaceuticals vaccine, as Janssen is owned by J&J. The J&J vaccine is a viral vector vaccine, which we will explore later on. Like the Moderna and Pfizer vaccines, it is administered into the muscle of the upper arm and some of its side effects have been described as pain, redness, and swelling at the injection site; tiredness, headache, muscle pain, chills, fever and nausea. It was reported as 66.3% effective in clinical trials and people had the most protection two (2) weeks after receiving the vaccine. The J&J vaccine has been reported by The Centers for Disease Control and Prevention has highly effective at “preventing hospitalization and death in people who did get sick.” In fact, no one who got COVID-19 at least four weeks after receiving the J&J vaccine had to be hospitalized, and early evidence suggests that it might actually offer protection against asymptomatic infection2.
What is a viral vector vaccine and how does that differ from the type of vaccine that Moderna and Pfizer produced? Well, viral vector vaccines use a modified version of a different virus, which is called the vector, to deliver necessary instructions to our cells. In the case of the J&J COVID-19 vaccine, the vector, which is not the virus that causes COVID-19, but a different, harmless virus, enters a cell in our body and then triggers the cell to produce a harmless piece of the virus that causes COVID-19, which is known as a spike protein3. The Moderna and Pfizer vaccines are a relatively new type of vaccine called mRNA vaccines, which were developed exclusively to protect the population against infectious diseases. Rather than using a weakened or inactivated germ, the vaccine actually teaches our cells to generate a protein, or a piece of a protein, that causes an immune response, enabling us to fight off the disease4.
At the end of the day, experts are imploring people not to get caught up in the details, but to ultimately respect the science and feel comfortable in knowing that each of the vaccines has been thoroughly vetted and tested and all are proven highly effective in the fight against COVID-19 infection. In fact, the American Medical Association Chief Health and Science Officer Mira Irons, MD, was quoted as follows: “Don’t get caught up necessarily on the numbers game, because it’s a safe and effective vaccine and what we need is to have as many effective vaccines as possible…” [rather than focusing on efficacy rates,] “accept the fact that now you have three highly effective vaccines5.”
That sounds great, but the question of one dose versus two still looms. On one hand, one dose means one trip to the vaccination site and one incidence of potential side effects. On the other hand, we are conditioned to believe that two might indeed be better than one when it comes to medication or treatment. University of California San Francisco infectious disease expert Monica Gandhi, MD, MPH, was asked about the science between one shot and simple advised that “the J&J vaccine went into Phase III trials as a one-dose vaccine because earlier phase trials had shown strong immune responses after just one dose. After one dose, across all populations, even in older people, the antibody response and T-cell response were excellent and increased over time6.” In other words, the data following one dose of the J&J vaccine was similar to that following two doses of the Moderna and Pfizer vaccines. Simply put, one dose works.
Questions emerge every day that call into question the effectiveness and utility of all three vaccinations; new strains and variants, asymptomatic patients, and the progressive return to “normal” life activities and events. However, while there is still some uncertainty and it is known that no identified vaccine can prevent all COVID-19 infections, all three approved vaccines offer a high level of protection against COVID-19 and seem to reduce the viral load in those who still become infected post-vaccination6.