J&J vaccine halted … so what?

Here’s what you need to know.

The J&J vaccine a “viral vector DNA” vaccine that is very different than the Pfizer and Moderna “messenger RNA vaccines” … and their long-term effects may be different.

Below is a very detailed analysis of the differences and their implications.

The J&J blood-clotting issue is a near-immediate injection side-effect that is very rare … less than a 1 in million occurrence … less likely than getting struck by lightning.

Statistically-speaking, the blood-clotting occurrence rate is so low that it raises questions as to why the vaccine has been halted.

Up until yesterday, most “experts” were saying “Take whichever vaccine is available to you first.”

Yesterday, Dr. Fauci and the other political-scientists were lock-stepping an “abundance of caution” message.  It will be interesting to see how this situation evolves, especially since…

For the record: Pfizer and Moderna vaccines were approved by the Trump administration; J&J was developed under the auspices of Trump’s Operation Warp Speed, but the J&J vaccine was approved by the Biden administration.

MUST READ: Here is a detailed recap of how the vaccines work and how they compare.  It’s long, but well worth the reading time.

The topline:

The 3 currently relevant brands (Pfizer, Moderna, J&J) are “well tolerated” (i.e. they exhibit few or no side effects) and provide high levels of protection …  with near total protection against hospitalization or death.

In clinal trials, Pfizer & Moderna scored higher in overall protection (roughly 95% against symptomatic infections) than the J&J vaccine (72%) in the U.S.

Most experts consider the difference in effectiveness rates to be more a function of when and where the clinical trials were done than the relative effectiveness of the vaccines.

Specifically, the J&J trial was done in a more “hostile” Covid environment: a higher prevalence of Covid and emergence of new Covid strains (especially the South African variant).


Regarding the variants…

“Laboratory studies and clinical-trial data suggest that all of the Covid  vaccines will provide significant protection (i.e. greater than 50% effectiveness) against emerging strains of the Covid virus.”  Source

It’s highly likely that an additional shot — either a booster or a reformulation — will eventually be required for all brands and types of vaccines to combat the variant strains.


It’s uncertain how effective the vaccines are preventing asymptomatic infections or how long the vaccines provide immunity against serious symptoms.

But, the consensus seems to be that there is very high protection against asymptomatic infections … and that the immunities last for at least several months, maybe longer.

That said, annual shots seem to be likely.

Again, the most compelling immediate effectiveness result to consider: all brands claim near total protection against hospitalization and death with unlikely side effects.

My take: Call it a push on effectiveness.


The J&J vaccine is easier to distribute since it requires less demanding refrigeration.

So, once production is ramped up, it will probably be more ubiquitous in rural areas and in low volume vaccination outlets (e.g. doctor’s offices, urgent care clinics and smaller pharmacies).

As well publicized, Pfizer & Moderna are currently administered in 2 doses with the 2nd dose following 3 or 4 weeks after the 1st.

The J&J vaccine only requires a single dose, making it a good fit for, say, high volume mass vaccination sites and for people who want the convenience of one & done (e.g. workers who are schedule constrained or people with limited access to distribution sites).

The Pfizer & Moderna vaccines are likely to be concentrated in, say, public health department vaccination clinics, targeted to high vulnerability populations.


That’s probably all that you really need to know, but if you’re interested in the comparative science of the vaccines, keep reading…


The New York Times ran a series on how the different vaccines work.

How the J&J vaccine works.
NYT J&J link  PDF J&J (w/ Homa highlighting)

How the Moderna vaccine works.
NYT Moderna link  PDF Moderna (w/ Homa highlighting)

Note: The Pfizer & Moderna vaccines are both mRNA vaccines that work essentially the same.

The articles are concise, translated into layman-speak and include great explanatory diagrams.

They are well worth reading!


For a quick read, here’s the essence…

There are 2 different “modalities”:

  • Pfizer and Moderna are Messenger RNA  vaccines (RNA: RiboNucleic Acid) which is shorthanded as mRNA
  • J&J is called a “Viral Vector DNA” vaccine (VV DNA)

Predecessor vaccines (e.g. for the flu) that inject small amounts of a pathogen (i.e. the virus) to trigger an immunity response.

Both mRNA and VV vaccines interact with a body’s cellular DNA.

Both Pfizer & Moderna mRNA vaccines are single- stranded RNA that penetrates our bodies’ cells and “instructs” the cell to produce proteins that elicit an immune system response: the production and circulation of virus destroying antigens.

J&J is a more durable double-stranded DNA that not only penetrates cells  but, more specifically penetrates cell nuclei where it is “read and copied” into mRNA which then acts comparably to the Pfizer and Moderna mRNA vaccines.

Both mRNA and viral vector vaccines have been researched for decades, but…

The mRNA vaccines (Pfizer and Moderna) have never before  been approved for use in any disease.  Source

The viral vector DNA vaccines (J&J) have been used successfully, but only for Ebola.

Because the recent clinical trials only tested the vaccines’ short-run effects … and because the vaccines have limited histories on other diseases … the long-term risks of the vaccines are uncertain.

It is claimed that mRNA is “fragile” and is “eventually destroyed by the cell, leaving no permanent trace” … and that viral vector DNA, while more durable than mRNA, is “rendered harmless (before insertion) and can’t replicate inside them or cause illness”.

If true, to long-term risks are minimal.

But again, the long-term risks are untested and uncertain.

Bottom line: It’s remarkable to have 3 approved vaccines this soon  … thanks to private industry innovation and Operation Warp Speed’s heroic stretch goals, risk-reducing financial supports and reduction of bureaucratic red tape.


DISCLOSURE: I got fully vaccinated with Moderna.

DISCLAIMER: I’m not a medical professional or scientist — just a curious, self-interested guy.  So, don’t take anything that I say or write as medical advice. Get that from your doctor!


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