Virus Experts Are Giving This New Warning to Some Fully Vaccinated People

A recent study has triggered an important alert about vaccine protection.

The U.S. had been experiencing a significant drop-off in COVID cases for weeks now, which has prompted officials to lift a number of restrictions and mandates. But even though we may be trending in the right direction, the decline is becoming less steep—and infections are rising again in certain states. According to the Centers for Disease Control and Prevention (CDC), cases were down by only 5 percent last week, while the decline had been in the double-digits the week prior. As the possibility of a new surge in infections draws near, you'll want to make sure you're as protected as possible from the virus.

RELATED: Virus Experts Just Gave This New COVID Warning—Even If You're Vaccinated.

A new study released March 29 from the CDC has given insight into the vaccine protectiveness of certain booster strategies. According to the results, fully vaccinated Americans who received the single-dose Johnson & Johnson vaccine appear to be better protected after getting an mRNA booster of either Pfizer or Moderna instead of another Johnson & Johnson shot.

From Dec. 2021 to March 1, independent researchers gathered data from over 80,000 emergency rooms or urgent-care visits and more than 25,000 hospitalizations among adults with COVID-like illness in 10 states. They found that just one shot of Johnson & Johnson provided an effectiveness of only 24 percent in preventing an emergency room visit and 31 percent against hospitalization during the height of the Omicron surge.

"That's too low, especially in this world where we have access to other things," Natalie E. Dean, PhD, a biostatistician at Emory University's Rollins School of Public Health, told The Washington Post. "One priority is making sure that people who only received one dose [of the Johnson & Johnson vaccine] are aware that they should go and get, preferably, a messenger RNA vaccine."

When comparing the effectiveness of different vaccine combinations, the researchers found that two shots of Johnson & Johnson were significantly less protective than any other vaccine and booster strategy. According to the study, the two shots were only 54 percent effective in preventing emergency room visits. On the other hand, three mRNA shots were 83 percent effective, while the combination of a Johnson & Johnson shot with one mRNA booster (Pfizer or Moderna) was still 79 percent effective.

"All eligible persons should receive recommended COVID-19 booster doses to prevent moderate to severe COVID-19. Adult [Johnson & Johnson] primary vaccine recipients should preferentially receive a heterologous mRNA vaccine booster dose [at least] 2 months later," the researchers stated.

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If you've already gotten a Johnson & Johnson booster, the data from the CDC's study suggests that a second booster shot with one of the mRNA vaccines might be necessary even after two Johnson & Johnson shots, Boghuma Titanji, PhD, an infectious-diseases expert at Emory University, told The Washington Post. On March 29, the CDC went ahead and approved a second booster of either Pfizer or Moderna's vaccine for any adults who received a Johnson & Johnson vaccine and booster at least four months ago.

But the agency did not say that these people necessarily should get this second booster, just that they are able to. "This is not yet a formal recommendation," Titanji noted, "but is something individuals who fall in this category should discuss with their health-care provider."

For those who haven't been vaccinated at all, virus experts are now warning that starting with Moderna or Pfizer instead of getting any Johnson & Johnson shots might be the best move. According to the CDC, around 24 percent of the eligible U.S. population still has not gotten their first shot of a COVID vaccine.

"The messenger RNA vaccines seem to be providing more protection," William Moss, MD, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, told The Washington Post. "What I'd like to see is a very simple recommendation: that everyone get three doses, and they should be messenger RNA vaccines."

RELATED: Dr. Fauci Just Issued a New Warning for Fully Vaccinated People.

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