Patient Care

Why the Johnson & Johnson vaccine is more effective than you think

Apr. 13, 2021

December 16, 2021 Update: CDC Expresses Clinical Preference for mRNA Vaccines

The CDC has endorsed recommendations of the Advisory Committee on Immunization Practices (ACIP) expressing a clinical preference for mRNA COVID-19 vaccines over the Johnson & Johnson vaccine. ACIP reaffirmed that receiving any approved vaccine is preferable to remaining unvaccinated, and the J&J vaccine remains available to individuals who choose it over mRNA vaccines from Moderna and Pfizer.

April 23 Update: Johnson and Johnson Vaccine

An expert panel voted to end the pause of the Johnson and Johnson vaccine today, reinstating its use in all people over the age of 18 in the U.S. The decision came after a 10-day pause in which experts carefully weighed the risk of a very rare blood clotting issue against the vaccine’s demonstrated benefits. Learn more about how they came to this decision and why you can still trust the Johnson and Johnson vaccine

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.”