CDC: Consider an mRNA Shot If You Received a J&J Vaccine and Booster

New data provide evidence of the benefits of mixing COVID-19 vaccines.

Doctor Injecting COVID-19 vaccine into patient's arm
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If you received a Johnson & Johnson (J&J) COVID-19 vaccine and booster, you may now be eligible to receive a second booster of either mRNA vaccine, the Centers for Disease Control and Prevention (CDC) announced Tuesday.

The announcement follows new data, also published Tuesday, in the CDC's Morbidity and Mortality Weekly Report (MMWR). According to the report, one dose of the J&J vaccine plus a booster dose of an mRNA vaccine (Pfizer-BioNTech or Moderna) is more effective in preventing COVID-19 than either one or two J&J doses alone. The findings underscore not only the extra protection mRNA vaccines can offer, but also the benefits of mixing COVID-19 vaccines.

"The Johnson & Johnson vaccine does provide some protection against severe illness, hospitalization, and death from COVID," Kimberly Giuliano, MD, chair of primary care pediatrics and leader of the vaccination distribution program at Cleveland Clinic, told Health.com. "However, the data has shown that mRNA vaccines—Pfizer and Moderna—provide greater protection. The bottom line is that J&J helps some, but mRNA vaccines help more."

Here's what to know about the new CDC recommendations, the data that inspired the change, and what to do if you previously received the Johnson & Johnson vaccine.

How Omicron Data Shaped the New Recommendation

The authors of the new MMWR report looked at data from 80,287 emergency department or urgent care visits and 25,244 hospitalizations that occurred in 10 states from December 16, 2021, to March 7, 2022, at which time Omicron was the predominant variant circulating in the U.S.

Those patients were categorized according to which vaccine or vaccine combination they received: unvaccinated, one J&J dose, two J&J doses, one J&J and one mRNA dose, and three mRNA doses.

Among emergency room (ER) or urgent care (UC) visitors, those who received only one J&J dose had the lowest vaccine effectiveness: one J&J dose was only 24% effective in preventing ER or UC visits. Even patients who received two J&J shots saw less protection (54%) than patients who received a J&J vaccine and an mRNA booster (79%), or three mRNA doses (83%).

In a hospital setting, receiving all three doses of an mRNA vaccine offered the best protection. Vaccine effectiveness dropped to 78% against hospitalization when a patient had received one J&J and one mRNA vaccine; it dropped again to 67% effective after two J&J doses.

According to researchers, the findings show that while three mRNA vaccine doses offer optimal protection against COVID-19, those who received a J&J primary dose may achieve similar protection with an mRNA booster dose. In that case, study authors recommend all patients who got J&J as their primary vaccine should receive an mRNA vaccine as their booster dose.

What This Means for You

The CDC announcement applies to anyone who has received a primary dose of the J&J vaccine, or a primary and booster dose of the J&J vaccine. For those who only received a single dose of the J&J vaccine, the CDC study suggests following up with an mRNA booster two months after your primary dose. Patients who received both a primary and booster J&J dose may get a second booster dose of an mRNA vaccine four months after their J&J booster.

Experts stress that there's no danger associated with receiving a different booster than your primary vaccine dose. "It is safe for those who have received one vaccine product to subsequently receive another," Dr. Giuliano said. "We can have a booster dose that is a different product than prior vaccines."

If both Pfizer and Moderna boosters are unavailable, people who received a primary J&J dose may still receive a J&J booster, according to the CDC. And if an mRNA vaccine is contraindicated for you, a J&J booster will suffice then, as well—it may not offer optimal protection, but some protection is better than none.

"Take whatever's available to you," Bernard Camins, MD, medical director of infection prevention at Mount Sinai Health System, told Health.com. "The J&J is still a really good vaccine."

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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