- There are now three COVID-19 vaccines authorized for use in the US.
- Pfizer’s and Moderna’s are mRNA-based, while Johnson & Johnson’s is an adenovirus.
- Dr. Anthony Fauci explained how they differ but have the same “end game.”
According to an article published in Business Insider, Dr. Fauci has a stunningly simple way to explain how Johnson & Johnson’s COVID-19 vaccine differs from Pfizer’s and Moderna’s shots.
Covid Vaccines in US
The US now has authorized three coronavirus vaccines: two mRNA options from Pfizer and Moderna, and one adenovirus shot from Johnson & Johnson.
While it’s true that Moderna’s and Pfizer’s shots were more effective overall than J&J’s in trials, experts have stressed that all these vaccines share two very important statistics: zero hospitalizations and zero deaths among fully vaccinated trial participants.
Vaccine Shots Comparisons
When asked which shot might provide people the best long-term protection from infection, including protection against worrisome virus variants like B.1.351, Florian Krammer, a leading virus expert, told Insider, “There’s little that can be said, for now.”
We do already know there are key differences in the way these two types of vaccines work.
During a White House briefing, President Joe Biden’s chief medical advisor, Dr. Anthony Fauci, explained exactly how each shot takes effect.
Boosting body
Pfizer’s and Moderna’s vaccines train the body to fight COVID-19 by injecting mRNA, or messenger RNA, into a person’s deltoid, the rounded muscle that hugs the upper arm and shoulder.
Spike protein
“The mRNA that’s injected into the muscle codes for the spike protein,” Fauci said.
The coronavirus’ spike protein is what allows the virus to latch on to and invade our cells. But the mRNA vaccines train our bodies to say, immunologically, “Not so fast.” “The body sees that [protein] and makes an immune response against that, giving you the protection that has been shown with both of the mRNA vaccines,” Fauci added.
J&J Shots
J&J’s shot injects viral DNA, not mRNA. This is a key reason J&J’s vaccine is so much easier to manufacture and to store in the fridge: The DNA inside is not as fragile as the single-stranded mRNA in Pfizer’s and Moderna’s shots.
That DNA is encapsulated in a “harmless, non-replication-competent virus,” Fauci said.
Vaccine working in body
That adenovirus, called Ad26, is a common cold virus that has had its illness-causing genes removed, so it can’t get you sick.
Once the vaccine is injected into a person’s arm, the virus injects its DNA into cells, where it’s copied into messenger RNA. That mRNA then codes for coronavirus spike proteins in the same way as Pfizer’s or Moderna’s shots.
End game
The “ultimate end game” of adenovirus and mRNA COVID-19 vaccines is the same, Fauci said.
“Both of the vaccines ultimately result in a spike protein in the right conformation that gives the body the opportunity to feel that this is the actual virus that it’s seeing,” he said.
To be clear, he added, it’s not the virus, “it’s the protein.”
That prepares a vaccinated person’s body to fight off a COVID-19 infection if the person comes into contact with the virus.
Vaccinations effect
Both the mRNA and the adenovirus vaccines appear to prevent the most severe COVID-19 infections very well: Pfizer’s and Moderna’s two-shot courses were more than 94% effective in their trials, while J&J’s was 85% effective in preventing severe disease and death.
Adenovirus vaccines like J&J’s might give people a more robust form of immunity against viral variants, with antibody and T-cell responses. (mRNA vaccines may provide only more narrow antibody protection.) But that remains to be seen as more people get vaccinated and variants continue to spread.
Experts view
Either way, experts agree that all three authorized vaccines need to work in concert in order to blunt the spread of the virus across the US and to help end the pandemic.
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Source : Business Insider
