Editor’s word: On Tuesday, Feb. 24, the U.S. Food and Drug Administration (FDA) launched the outcomes of its trial of the Johnson & Johnson coronavirus vaccine. The FDA discovered the vaccine to be secure and efficient, and it’s anticipated to grant emergency use authorization within the coming days. Maureen Ferran, a virologist on the Rochester Institute of Technology, explains how this new vaccine works and explores the variations between it and the already permitted Moderna and Pfizer–BioNTech vaccines.
1. How does the Johnson & Johnson vaccine work?
The Johnson & Johnson vaccine is what’s referred to as a viral vector vaccine.
To create this vaccine, the Johnson & Johnson staff took a innocent adenovirus – the viral vector – and changed a small piece of its genetic directions with coronavirus genes for the SARS-CoV-2 spike protein.
After this modified adenovirus is injected into somebody’s arm, it enters the particular person’s cells. The cells then learn the genetic directions wanted to make the spike protein, and the vaccinated cells make and present the spike protein on their very own floor.
The particular person’s immune system then notices these international proteins and makes antibodies in opposition to them that may defend the particular person if they’re ever uncovered to SARS-CoV-2 sooner or later.
The adenovirus vector vaccine is secure as a result of the adenovirus cannot replicate in human cells or trigger illness, and the SARS-CoV-2 spike protein cannot trigger COVID–19 with out the remainder of the coronavirus.
2. How efficient is it?
The FDA’s analysis discovered that, within the US, the Johnson & Johnson COVID-19 vaccine was 72 % efficient at stopping all COVID-19 and 86 percent effective at preventing severe cases of the disease.
While there’s nonetheless an opportunity a vaccinated particular person might get sick, this implies they might be a lot much less more likely to want hospitalization or to die from COVID-19.
An identical trial in South Africa, the place a brand new, extra contagious variant is dominant, produced comparable outcomes. Researchers discovered the Johnson & Johnson vaccine to be barely much less efficient at stopping all sickness there – 64 % total – however was nonetheless 82 % efficient at preventing severe disease.
The FDA report additionally signifies that the vaccine protects against other variants from Britain and Brazil too.
3. How is it totally different from the Moderna and Pfizer vaccines?
The most simple distinction is that the Johnson & Johnson vaccine is an adenovirus vector vaccine, whereas the Moderna and Pfizer vaccines are each mRNA vaccines.
Messenger RNA vaccines use genetic directions from the coronavirus to inform an individual’s cells to make the spike protein, however these do not use one other virus as a vector. There are many practical differences, too.
Both of the mRNA-based vaccines require two pictures. The Johnson & Johnson vaccine requires only a single dose. This is vital when vaccines are briefly provide.
The Johnson & Johnson vaccine can be saved at a lot hotter temperatures than the mRNA vaccines. The mRNA vaccines have to be shipped and saved at under–freezing or subzero temperatures and require a complicated cold chain to soundly distribute them. [Ed. note: The FDA announced Thursday that Pfizer’s vaccine can be stored at temperatures found in pharmaceutical freezers for a period of up to two weeks.]
The Johnson & Johnson vaccine will be saved for a minimum of three months in a regular refrigerator, making it a lot simpler to make use of and distribute.
As for efficacy, it’s troublesome to immediately examine the Johnson & Johnson vaccine with the mRNA vaccines resulting from differences in how the clinical trials were designed.
While the Moderna and Pfizer vaccines are reported to be roughly 95 % efficient at stopping sickness from COVID–19, the trials have been accomplished over the summer and fall of 2020, earlier than newer, more contagious variants were circulating widely.
The Moderna and Pfizer vaccines may not be as efficient in opposition to the brand new variants, and Johnson & Johnson trials have been accomplished extra lately and keep in mind the vaccine’s efficacy in opposition to these new variants.
4. Should I select one sort of vaccine over one other?
Although the general efficacy of the Moderna and Pfizer vaccines is larger than the Johnson & Johnson vaccine, you should not wait till you’ve your selection of vaccine – which is probably going a good distance off anyway. The Johnson & Johnson vaccine is almost pretty much as good because the mRNA-based vaccines at stopping serious disease, and that is what actually issues.
The Johnson & Johnson vaccine and different viral-vector vaccines just like the one from AstraZeneca are notably essential for the global vaccination effort.
From a public well being perspective, it is essential to have multiple COVID-19 vaccines, and the Johnson & Johnson vaccine is a really welcome addition to the vaccine arsenal. It does not require a freezer, making it a lot simpler to ship and retailer. It’s a one-shot vaccine, making logistics a lot simpler in contrast with organizing two doses per particular person.
As many individuals as attainable have to be vaccinated as shortly as attainable to limit the development of new coronavirus variants. Johnson & Johnson is anticipated to ship out practically four million doses as quickly because the FDA grants emergency use authorization.
Having a 3rd approved vaccine within the US will likely be an enormous step in the direction of assembly vaccination demand and stopping this pandemic.