The latest approved vaccine candidate by Johnson & Johnson for people over the age of 18 started shipping last week, shortly after receiving the Food and Drug Administration emergency use authorization. Approximately 4 million doses are to be distributed in the United States, with a total of 20 million by the end of the month. President Joe Biden announced last week that the pharmaceutical company Merck & Co will step in to help produce the vaccine in a collaboration we have not seen since WWII.


J&J's candidate requires only one dose, while Moderna Inc and Pfizer both need to be administered twice. Both of these vaccines require extremely cold temperatures which greatly complicates delivery and storage, while J&J's vaccine can be kept at normal refrigerated temperatures which opens up possibilities for delivery to remote areas that are far from major medical centers.

Similar but different technology compared to Pfizer and Moderna

J&J used a similar, but slightly different technology than Pfizer and Moderna who used messenger RNA to direct the body to make the virus' spike protein. Their vaccines enclose their mRNA in lipid nanoparticles, which is what caused the problem of ramping up production and contributed to bogged-down supply chain issues. Once the cells create the spike protein found on the coronavirus, the immune system can react when exposed to the real thing. Basically, the mRNA vaccines train our bodies to say "not so fast".

On the other hand, J&J's shot injects viral DNA and this is a key reason why this vaccine is easier both to manufacture and store in the fridge because DNA is not as fragile. Once the vaccine is injected, the DNA is copied into messenger RNA within cells. That mRNA then codes for coronavirus spike proteins, which is what Pfizer's or Moderna's shots do.


The Johnson & Johnson vaccine is 85% effective at preventing moderate to severe illness in trials and 66% effective in preventing symptomatic illness 28 days after vaccination, compared to about 95% for the Pfizer and Moderna vaccines. But it's still a high number as the flu vaccine reduces the risk of illness by between 40% and 60%. More importantly, it seems J&J's vaccine is effective against several COVID-19 variants.

JNJ's candidate also comes with milder side-effects

Side effects are slightly milder and less commonly reported than with the Pfizer and Moderna vaccines, with the most common ones being fever and fatigue. But side effects are not adverse effects. Adverse effects are unintended and detrimental such as an allergy, and all approved vaccines against COVID-19 did a great job in avoiding them. As for side-effects, these vaccines are actually designed to produce them because they actually show that the immune system is responding. But, it doesn't necessarily mean stronger side effects are resulting in better protection against COVID-19.

The silver lining

The bottom line is that all vaccine types result in the same ‘end game' for the virus and they are all equally valuable in ending the pandemic. Every crisis has a silver lining, and so does this global health crisis that made pharmaceutical rivals join forces. It is thanks to this kind of collaboration that science made remarkable progress by delivering an approved vaccine within less than a year, something that usually takes a decade with many biotech and pharmaceutical companies even spending several decades and valuable resources without managing to produce a single approved drug. That is how powerful synergy is because when people come together for the right reasons, magic happens. If this is the lesson we learned from a global pandemic, we will emerge from this global crisis stronger.

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