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.
Yes, there are more similarities between solar cells and pizza than you might think.
I'm a solar energy researcher working towards eliminating the defects in and improving the performance of industrial solar cells. A PhD is a long journey full of untimely experiments and countless sleepless nights, so I often find myself eating while working (definitely not in the labs!) and working while eating. One day, intrigued by how delicious a cheese pizza is, I realized how alike the pizza and the cell samples I work with are.
Build your own Solar Cell
A solar cell is a device that generates electricity when the sun shines over it. A combination of these cells linked in sequence makes a solar panel that can generate significant power, and that is what you see on people's rooftops, in solar-powered streetlights, and calculators. As a good pizza starts with a perfect dough base, solar cells begin with a very pure form of silicon wafer (which is also the second most abundant element in the Earth's crust), scientifically called a 'base.' Some extra elements like boron or phosphorus are then added to this silicon base to make it more conductive.
Then comes the toppings. Yes, both for the pizza and the cells! Pizzas are loaded with a bunch of toppings for various flavors; solar cells are also coated with some very thin layers that help enhance their performance. These layers are called 'dielectrics.' They help reduce the reflection off the surface to increase the light absorption, passivate some surface defects, and possess some hidden benefits for the base. The most common dielectric, silicon nitride, used in the industry is also responsible for the blue color you see on most solar panels (a silicon wafer is otherwise grey!).
We all know that pizza does not taste great after sitting in the fridge for a week. A similar degradation occurs in most solar cells. Once the panels are installed and are out in the sun, their performance degrades after the first few years (anywhere between 2-10% relatively). And losing a slice or two of a pizza might not make a dent in your pocket, but this degradation is responsible for a loss of billions of dollars every year. We call it 'light-induced degradation' (or LID).
Light-Induced degradation (Staleness)
LID is a family of defects that occur in the presence of light; however, technically speaking, the resulting charge carriers are responsible, not the light. This degradation is not a new phenomenon, and researchers have been working on understanding and solving it for years. The good news is one of the most common defects responsible for LID has now been nearly solved in most panels worldwide. Unfortunately, we now have a new variant of LID in all kinds of panels. However, it only occurs at high-temperatures under light: "light- and elevated temperature-induced degradation," or LeTID. More sunlight is essential for higher electricity generation from the solar panels, but higher temperatures are detrimental (we only need the light, not the heat, for solar electricity generation).
This new kind of degradation is a focus of numerous researchers globally, including me. In my research, I work on mitigating this degradation by simply playing with the dielectrics (after all, it is all about the toppings, right?).
Firstly, we have found that reducing the thickness of the dielectrics can significantly mitigate this degradation (1). You can imagine how applying less tomato sauce can prevent the pizza from going soggy. Reducing the thickness means using less material and thus lower costs. However, there is a threshold beyond which reducing the thickness might lead to other kinds of losses.
Secondly, we also devised that the placement of the dielectrics plays a vital role in the extent of potential degradation (2). By studying multiple industrial cells, it was observed that adding a very thin layer of a second dielectric can strongly modulate the degradation. This reduced the degradation by creating a barrier layer between the first dielectric (Silicon nitride) and the silicon base. Another solution we found is the dependence of degradation on the silicon wafer thickness (3). By thinning the wafers, severely low degradation was observed. Similar to how a thin-crust pizza can help prevent you from gaining extra calories if you are on a diet!
These three solutions effectively alleviate the degradation in current solar cells without increasing their manufacturing cost. With solar installations progressing at record levels each year, the mitigation of these defects will accelerate the transition to a cleaner world. So, we can leave the next generations with tastier pizzas and a healthier planet!
1. U. Varshney, M. Abbott, A. Ciesla, D. Chen, S. Liu, C. Sen, M. Kim, S. Wenham, B. Hoex, and C. Chan, "Evaluating the Impact of SiNx Thickness on Lifetime Degradation in Silicon," IEEE J. Photovoltaics, vol. 9, no. 3, pp. 601–607, 2019.
2 . U. Varshney, C. Chan, B. Hoex, B. Hallam, P. Hamer, A. Ciesla, D. Chen, S. Liu, C. Sen, A. Samadi, and M. Abbott, "Controlling Light- And Elevated-Temperature-Induced Degradation with Thin Film Barrier Layers," IEEE J. Photovoltaics, vol. 10, no. 1, pp. 19–27, 2020.
3. U. Varshney, M. Kim, M. U. Khan, P. Hamer, C. Chan, M. Abbott, and B. Hoex, "Impact of Substrate Thickness on the Degradation in Multicrystalline Silicon," IEEE J. Photovoltaics, vol. 11, no. 1, pp. 65–72, 2020.
If I had to go back in time and give myself advice, I’d tell myself to be cautious of advice. Advice isn’t necessarily good or bad, but it’s often misguided or the wrong fit. In your scientific career, especially early on, it’s tempting to trust all the guidance tossed your way. More experienced scientists should know better than you, right? Not necessarily.
Here’s some advice I received and learned — through experience — to disregard.
An upside to academia is the freedom to make your own choices. But with freedom comes uncertainty. Grad school and science careers are challenging to navigate. Suitable, appropriate guidance will help you through, while erroneous, biased advice can hold you back. Practice healthy skepticism, and in the end, always choose what's best for you.
Have you been given extraordinarily ill-fitting advice as a scientist? If so, tell us in the comment section below! Or, tweet at us, @BoldedScience, #BadAdvice.