Johnson and Johnson recently announced that they have met their COVID-19 vaccine trial’s primary endpoint. They are now seeking Emergency Use Authorization from the FDA for their one-dose vaccine for Sars-Cov-2 called JNJ-78436735 or Ad26.COV2.S by J&J’s pharmaceutical arm Janssen who developed the product.
A meeting will be held on February 26, 2021, to determine if the first single-dose vaccine will receive emergency use authorization. According to Johnson and Johnson the vaccine is overall 66% effective in preventing moderate to severe COVID-19, 28 days after vaccination. Unlike Pfizer and Moderna this vaccine leverages a more traditional vaccine technology called AdVac.
Instead of using mRNA, AdVac is a vector (carrier) technology, the vector is based on a genetically modified version of the adenovirus, which carries in the genetic code of an antigen (pieces of viruses, bacteria, or pathogens). Explained by Janssen:
“The AdVac® technology works by using an adenovirus as a vector (a carrier) of an antigen’s genetic code, to mimic components of a pathogen (a bacterium, virus, or other disease-causing organisms). Antigens (components of a pathogen) are produced to mimic the pathogen, without causing severe disease.”
Although this technology has produced several vaccine candidates for viruses such as HIV, RSV, and Zika it has never been licensed in the United States. The previously mentioned vaccines are currently only candidates. Janssen’s Ebola two-dose regimen vaccine Zabdeno® (Ad26.ZEBOV) and Mvabea® (MVA-BN-Filo), was approved by the European Commission. However, this is the only vaccine based on this technology to receive any kind of approval.
With few vaccines of this type, and none currently on the market in the US, or many other countries, it is difficult to know the future outcomes of a Sars-Cov-2 vaccine made with this technology.
The technology claims to activate both the humoral immune response as well as a “cellular immune response“. However, the video does not specify if the “cellular immune response” it speaks of is a truly cell-mediated response or a TH2 response. If it is truly able to activate a balanced TH1and TH2 response it would be the first vaccine to do so. Traditional vaccines favor a TH2 response, and although TH2 is said to be “anti-inflammatory,” it is more likely to induce long term inflammatory effects and lead to less cell memory. This is the reason that multiple doses and booster shots are required after the initial vaccination. Vaccine immunity wanes over time because it is TH2 weighted and the cells are not able to induce sufficient memory.
Similar to the AstraZeneca shot, there are also questions about residual human DNA in the J&J vaccine.
As seen above, J&J has used PER.C6, a human fetal cell line. According to Creative Biolabs, which help to produce cell lines including PER.C6:
“The PER.C6 cell line is derived from human embryonic retinal cells, originally from the retinal tissue of an 18-week old fetus aborted in 1985 and further developed and prepared as cell line by transfection with defined E1 region of the adenovirus type 5 followed by selection for transfectants with an immortal phenotype.”
This would explain why AdVac technology, being used by J&J, utilizes PER.C6 cells. They were prepared with adenovirus type 5 which is what the AdVac technology is all about, using vectors created from genetically modified adenoviruses to transport antigens.
Of course, this presents ethical complications as well as possible health risks for those considering getting this brand of the vaccine.
There is much more to cover about J&J’s vaccine trials leading up to EUA. I will be writing about these in more detail in a future post. However, for now, please note that J&J added a co-primary end-point and changed many of its stipulations surrounding calculating efficacy shortly before announcing its “successful” reaching of the study’s endpoint.
Lastly, of course we will be adding Johnson and Johnson’s new vaccine to our guide, Everything You Need to Know About the COVID-19 Vaccine– specifically if it received Emergency Use Authorization from the FDA.