Medical staff prepares a vaccine for waiting patient.

March 18, 2021

Q. How is the vaccine different from the Moderna and Pfizer vaccines?

A. Unlike the others, the Johnson & Johnson vaccination only requires one dose. So with it, you’re “one and done.” Within 4 weeks, you’ll have its full benefits via a single dose.

Johnson & Johnson says it will be able to produce 20 million shots by the end of this month—and 100 million by the end of summer.

This will help America satisfy demands for vaccinations, which currently far exceed the supply. Having three anti-COVID-19 vaccines speeds the mission to protect as many Americans as possible.

As of the beginning of March 2021, more than 31 million American adults—9.4% of the total population—have been fully vaccinated. Overall, 93.6 million shots have been administered, reports the U.S. Centers for Disease Control and Prevention.

The more people who are immunized, the closer we are to a post-pandemic—and normal—life.

Q. How effective is the new vaccine?

A. All three vaccines have been found to be 100% effective in preventing hospitalizations and deaths from COVID-19.

There’s also a payoff for those who initially tested positive with minor symptoms. They’ll be 65.5% more likely to escape troubling long-term shortness of breath, coughing and chest or abdominal pain.

Q. How does the vaccine work?

A. Unlike the Moderna and Pfizer vaccines, Johnson & Johnson’s uses viral vectors, which were proven successful in fighting an Ebola outbreak in 2014.

The goal is to disarm coronavirus’ outer spike proteins—and thus the disease.

That’s accomplished by taking the common cold virus, rendering it ineffective and using it to ship to healthy cells a blueprint of harmful coronavirus spikes.

Thus armed, your immune system recognizes—and attacks—the spike protein and COVID-19 itself.

Q. Do I get to choose which vaccine I get?

A. Most likely you won’t be offered a choice—but the sooner you’re vaccinated, the sooner you reduce your risk of being hospitalized or dying from the coronavirus.

Rest assured all three vaccines are worthy warriors against the virus that has killed more than 527,700 Americans.

The U.S. Food and Drug Administration backs the Johnson & Johnson vaccine, which was approved in the U.S. on Feb. 27, 2021. It already has been given in Great Britain and Latin America. There are wait lists for other cities around the world.

Q. Does the Johnson & Johnson vaccine have special benefits?

A. Many people feel soreness where the vaccine was injected. But fewer than half of people suffer fatigue, headaches or muscle pain.

Learn more about the COVID-19 vaccine here »


In Dec. 2021, the CDC issued a preferential recommendation for the use of the mRNA COVID-19 vaccines currently available in the U.S. (Pfizer and Moderna) over the Johnson & Johnson vaccine, citing rare but serious side effects. Throughout the pandemic, Memorial Hermann has closely followed guidance from the CDC as well as the U.S. Food & Drug Administration (FDA) and the State. As such, Memorial Hermann now recommends the Pfizer and Moderna COVID-19 vaccines over the Johnson & Johnson vaccine for those who meet vaccine eligibility.

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