I didn’t write any stories today, so here is a good story that I read:

In other news (outlets)

STAT: Comparing the Covid-19 vaccines developed by Pfizer, Moderna, and Johnson & Johnson

This article was published Feb. 2 but last updated March 3 (as of when I am linking to it).

It looks like all three vaccines target the spike protein the SARS-CoV-2 virus, which is the protein that is different in the three variants that the U.S. Centers for Disease Control and Prevention are tracking.

Also, all of these vaccines take time to work (obviously).

Both the Moderna and the Pfizer vaccines require two shots: a priming dose, followed by a booster shot. The interval between Moderna doses is 28 days; for the Pfizer vaccine, it’s 21 days.

Also from the article:

Pfizer started counting cases from seven days after receipt of the second dose of vaccine, while Moderna waited until day 14 to start counting cases.


Each dose of Pfizer’s contains 30 micrograms of vaccine. Moderna went with a much larger dose of vaccine, 100 micrograms. It means the company is using a little more than three times as much vaccine per person as Pfizer is. And yet, they aren’t getting better results.

Ongoing studies

If you’re having a thought right now that J&J or Moderna should test this or that next, they might already be doing that. The article says that these tests are currently going on:

  • J&J is testing a two-dose regimen administered eight weeks apart. It is a 30,000 trial that could yield results sometime in May.
  • J&J is testing what happens if you give a single dose recipient a booster a while later.
  • Moderna, at the government’s request, is testing at a lower dosage (like the Pfizer vaccine).

Side effects are as rare as they are with most vaccines.

J&J recently revealed that a single case of anaphylaxis has been reported in someone who received its vaccine.

It will take time to come up with a firm estimate of how frequently this side effect occurs. The most recent data from the CDC suggest that anaphylaxis occurs at a rate of about 2.5 cases per one million doses given of the Moderna vaccine, and 4.7 cases per million doses of the Pfizer. Many of the people who have developed anaphylaxis have a history of severe allergies and some have had previous episodes of anaphylaxis.

Storage requirements on the Pfizer vaccine have loosened.

Of the mRNA vaccines, Pfizer’s was originally the more difficult to use. It had to be shipped and stored in ultra-cold freezers — ones that could keep the vials at -94 degrees Fahrenheit. But recently, the FDA announced that the vaccine can be shipped and stored — for a two-week period only — at temperatures of normal pharmacy freezers, between -13 and 5 degrees Fahrenheit. That should make the final stage of the vaccine’s journey from production plant to syringe ready to plunge into an arm somewhat easier.

Durability of protection

Figuring out how long the protection provided by any of these vaccines will last will take time. It’s going to involve periodic blood draws from some volunteers to see what their antibody levels look like, though a decline in antibody levels doesn’t necessarily equate to loss of protection.

But a large part of this work will involve watching for reports that people who were immunized are starting to contract Covid in larger numbers, a development that would probably lead to recommendations to give people booster shots at some yet-to-be-determined interval.