Patient Care

J&J COVID Vaccination Pause

Apr. 13, 2021

Updated - April 13, 2021

Today the CDC and FDA issued a statement recommending a pause in the use of the Johnson & Johnson (J&J, also known as Janssen) COVID vaccine out of an abundance of caution. New York State announced that it will follow this guidance.

The CDC and FDA are reviewing data involving six cases of an extremely rare and severe type of blood clot among recipients of the more than 6.8 million doses of the J&J vaccine that have been administered in the U.S. to date. All six cases reportedly occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination. 

Patients scheduled to receive J&J vaccine through UR Medicine will have the option to receive either the Pfizer-BioNTech or Moderna vaccine while the pause is in effect.

Today’s news raises understandable concerns among people who have recently received the J&J vaccine. People who develop severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their health care provider.

It’s important to remember that this side effect is extremely rare, and the pause is evidence of scientists and doctors working with extreme caution to ensure vaccines are as safe and effective as possible. People should continue to schedule vaccinations at their earliest opportunity, which is essential to saving lives and bringing an end to the COVID pandemic.

If someone was giving away $100 million to your neighbor but offered you $95 million instead, would you take it?

It’s a scenario that Dr. Louis J. Papa, a UR Medicine primary care internist, shares with his patients who ask about the difference between the newly approved Johnson & Johnson Covid-19 vaccine versus ones from Pfizer and Moderna.

In clinical trials, the J&J vaccine showed 66% overall efficacy against Covid-19 while the other vaccines showed percentages around 95%. But, Dr. Papa explains, those aren’t the numbers that matter. The question is how well the vaccines protect against serious disease.

In Johnson & Johnson’s published results, its vaccine was 85% effective in preventing severe disease and, most important, “demonstrated complete protection against COVID-19 related hospitalization and death as of Day 28.”

So no matter which approved vaccine you get—just like whether it’s $100 million or $95 million appearing in your bank account—you’ll be set.

“You still have to mask and stay socially distant to protect other people—but you’re free, Dr. Papa explains. “You’re protected. It’s an enormous freedom that gets you out from under all this. All these vaccines are very effective.”

In truth, the efficacy numbers are often misunderstood.


Dr. Angela Branche, an infectious disease researcher at University of Rochester Medical Center who played a major role in Covid-19 vaccine trials last year, notes that the overall effectiveness percentage is a measure of “the ability of the vaccine to prevent any sort of infection that is symptomatic.”

The “ineffective” percentage could mean something as simple as a runny nose or a temporary loss of smell.

“If 30 out of 100 people who get the vaccine get a cold, does it really matter?” Dr. Branche asks. “If we have 70 percent who never get infected at all, and the remaining 30 may have asymptomatic infection or a really minor cold, then that’s an extremely successful vaccine.”

And the J&J vaccine requires only one dose, not two. That helps people who can’t easily get to a second vaccination appointment, but Dr. Branche also notes that one dose means fewer reactions in most people.

And in the end, one vaccine might work better than another in a particular person, regardless of efficacy rates from a trial.

“We can’t predict with any degree of certainty that one vaccine is going to be the best fit for you,” Dr. Branche says. “So because they’re all really good vaccines, and they all offer really good protection, if you have the opportunity to get a vaccine, get the one that’s available.”

She adds, “the bottom line is that nobody who has gotten these vaccines has died from Covid.”