Johnson & Johnson's COVID-19 Vaccine: How Does It Work?

By Sheeva Azma (of Fancy Comma) and Nidhi Parekh (of The Shared Microscope) 

Operation Warp Speed, launched in early 2020, helped speed up the pace of vaccine innovation, turning the normally 10+ year clinical trials process into one that takes less than a year. To learn more about the vaccine development process, check out this post by Nidhi.

Although vaccine development has been significantly accelerated, it is essential to understand that vaccine development has not been rushed. In fact, despite operating in a public health emergency (the COVID-19 pandemic), vaccine research has been thriving. This is thanks to scientific collaboration, funding, and a quick and thorough review process, allowing scientists across the globe to develop the COVID-19 vaccines in under a year. 

In this article, we will discuss Johnson & Johnson's COVID-19 vaccine. The Johnson & Johnson (J&J) vaccine will likely be approved by the US Food and Drug Administration (FDA) for use by late February or early March. The J&J vaccine is different from other COVID-19 vaccines in that it only requires one dose. As such, it may be the saving grace to the seemingly slow and clunky vaccination rollout in various countries, including the United States.

Why might the J&J vaccine be the pandemic saving grace?

The J&J vaccine may be the next one to receive approval -- i.e., after the Moderna vaccine and the Pfizer vaccine. There are various advantages and disadvantages to using this vaccine.

The biggest drawback of the J&J vaccine is that it has lower efficacy than the Moderna and Pfizer vaccines. To understand the science of vaccine efficacy better, check out Sheeva's post. More specifically, the J&J vaccine has an efficacy of 72% in the United States, 66% in Latin America, and 57% in South Africa. By contrast, Moderna's COVID-19 vaccine has an efficacy of 94.5%, and the Pfizer COVID-19 vaccine has an efficacy of 95%.

Despite the lower efficacy rate, the J&J vaccine remains quite promising. The vaccine only requires a single dose, significantly simplifying the logistics required for local health departments and clinics. Additionally, the vaccine is stable in a refrigerator for several months (36°F - 46°F or 2°- 8°C). Contrarily, other vaccines, such as the Moderna and Pfizer vaccines, require freezing at significantly lower temperatures of -4°F or -20°C and –94°F or –70°C, respectively.

Johnson & Johnson's COVID-19 vaccine and the AdVac technology

The Johnson & Johnson vaccine in development (which is now seeking FDA approval in the United States) goes by two names -- JNJ-78436735 or Ad26.CoV2-S. The vaccine is developed by J&J's pharmaceutical arm, Janssen, using Johnson & Johnson's AdVac technology.

According to the Janssen website, AdVac technology is "based on development and production of adenovirus vectors (gene carriers)." The AdVac technology enables effective development of an adenovirus-based vaccine in response to emerging diseases, such as COVID-19, in a cost-effective and large-scale manner. 

What is an adenovirus-based vaccine?

To explain what an adenovirus-based vaccine is, we first have to talk about the basics of viral vector vaccines. The Oxford/AstraZeneca and J&J vaccines are both viral vector immunizations, meaning that a non-infectious virus is used as a shuttle to deliver the virus's genetic contents into our bodies. 

Think of a viral vector vaccine as a "cut-and-paste" vaccine. Parts of one virus are cut and pasted into another to create a viral vector vaccine. An adenovirus-based viral vaccine uses part of an adenovirus as a shell and a gene encoding a part of another virus (such as the novel coronavirus) is shoved into that shell.

In both the Oxford and J&J viral vector vaccines, the gene encoding the coronavirus spike protein is pasted into a "hollow" shell of an adenovirus. J&J specifically uses an adenovirus strain named adenovirus 26 (Ad26). When the vaccine (i.e., the Ad26 shell and with the spike protein center) is administered, it invokes an immune response in the body. (Learn more about the spike protein here.) 

After being vaccinated, our body will be able to respond to the virus more effectively to eliminate the risk of infection. This is done through the quick and effective recruitment of immune cells and antibodies to prevent the virus from inducing COVID-19 disease. To learn more about J&J's COVID-19 vaccine, check out Nidhi's post here. You can also learn more about the other top COVID-19 vaccines here.

Johnson & Johnson's FDA Emergency Use Authorization

On February 24, 2021, the FDA granted Emergency Use Authorization (EUA) for J&J's single-shot COVID-19 vaccine. The company's EUA approval is based on the efficacy and safety data from the Phase 3 trials. The J&J vaccine will be a pivotal step towards putting an end to the pandemic due to its single-dose requirements that also require normal refrigeration rather than super cold storage.

Author

Nidhi Parekh blogs at The Shared Microscope.  You can follow her work on Twitter, Facebook, and Instagram for informative, effective illustrations of concepts in biology.




​Sheeva Azma is a founder and lead writer/researcher at science writing company Fancy Comma, LLC, which can be found on LinkedIn, Facebook, Twitter, and Instagram.Write something about yourself. No need to be fancy, just an overview.