The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that causes COVID-19 pandemic has spread to over 220 countries and territories around the world as of July 2021. Up to the last 30 days, the ongoing pandemic has been causing ~186 million reported cases and ~4.0 million deaths globally. (1)
In response to global health crisis in 2020, the U.S. Secretary of the Department of Health and Human Services (DHHS) declared a public health emergency that justifies the emergency use of drugs and biological products during the COVID-19 pandemic. On December 11, 2020, the U.S. Food and Drug Administration (FDA) issued the first emergency use authorization (EUA) under Section 564(b)(1) of the FD&C Act for a vaccine for the prevention of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals 16 years of age and older. (2-3)
Currently, there is no effective therapeutics for COVID-19, the only way to return to normal lives may be with safe and efficacious vaccines. To date, three COVID-19 vaccines under Authorized for Emergency Use in the US: Moderna (age 18+), Pfizer-BioNTech (age 12+) and Johnson & Johnson/Janssen (age 18+) (4). These are not fully approved vaccines to prevent COVID-19.
Janssen And AstraZeneca COVID-19 Vaccines Under EUA of Use
On February 27, 2021, the FDA issued EUA for the unapproved or licensed product, Janssen COVID-19 Vaccine, for active immunization to prevent Coronavirus Disease 2019 (COVID‑19) in individuals 18 years of age and older. (5-6)
However, AstraZeneca COVID-19 Vaccine is indicated for active immunization of individuals 18 years of age and older for the prevention of coronavirus disease 2019 (COVID-19), (7) but it has not yet been approved by the FDA, because the FDA requested AstraZeneca to show results from a large-scale clinical trial.
Two Vaccines, Same Technology
The Janssen and AstraZeneca COVID-19 vaccines use the same technology， which is an adenovirus, a common type of virus that typically causes mild cold symptoms when it infects someone.
COVID-19 viral vector vaccines inject a harmless adenovirus vector, which introduces unique genetic information from the COVID-19 virus to human cells. But both vectors are biologically different and not interchangeable.
The Janssen’s COVID-19 vaccine is composed of a recombinant, replication-incompetent human adenovirus type 26 vector, that, after entering human cells, expresses the SARS-CoV-2 spike (S) antigen without virus propagation. An immune response elicited to the S antigen protects against COVID-19. (8)
Janssen’s vaccine has several benefits over AstraZeneca, which makes them easier to store and transport. It can be kept refrigerated rather than frozen with longer shelf life and a single-dose regimen. This type of vaccine is good for rural areas without health care sites.
While AstraZeneca vaccines are ChAdOx1-S recombinant vaccines, (chimpanzee version), a non-replicating cold virus known as an adenovirus to deliver spike proteins into cells and produce an immune response. (7)
Recent data (9) indicated that doses of the AstraZeneca vaccine also contain significant amounts of protein from human cells—presumably from the human cell line used to grow the virus during the manufacturing process.
Cross-Contamination of Covid-19 Vaccines
In late March 2021, employees at a biodefence plant, Emergent Biosolutions in Baltimore accidentally mixed ingredients (cross-contamination) of Johnson & Johnson and AstraZeneca vaccines, contaminating 15 million doses of the Johnson & Johnson product. (10)
FDA officials learned in April that up to 15 million doses of the Johnson & Johnson vaccine had been contaminated with the vaccine developed by AstraZeneca, then, FDA ordered Emergent Biosolutions to stop producing vaccines for Johnson & Johnson and AstraZeneca and to works...
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