The Biden administration announced Tuesday that the U.S. pharmaceutical company Merck would help make Johnson & Johnson’s COVID-19 vaccine, a partnership between two rivals that should dramatically increase supply. The news comes after the Food and Drug Administration issued an emergency use authorization on Feb. 27 for the Johnson & Johnson vaccine, the third to be produced and approved for use in the U.S. The company is planning to quickly distribute nearly 4 million doses of the single-shot vaccine, adding to the growing daily inoculations already being given with two-dose vaccines by Pfizer and Moderna.
While most Americans will not have a choice about which vaccine they receive, since supply remains somewhat scarce as health officials seek to inoculate those who are most vulnerable, the fact that three vaccines are now available raises several questions.
How is the Johnson & Johnson COVID vaccine different from Pfizer’s or Moderna’s?
The Johnson & Johnson vaccine is more flexible, according to Yahoo News Medical Contributor Dr. Kavita Patel. The Pfizer and Moderna vaccines require two doses to fully protect against COVID-19, whereas the Johnson & Johnson vaccine is a single shot. It can also be stored in refrigerators, while those by Pfizer and Moderna require subzero-temperature storage — a factor that complicates distribution.
Patel said it’s also important to note that the technology used in Johnson & Johnson’s vaccine is different. The Pfizer and Moderna vaccines use a technology called messenger RNA. “The vaccine sends, like a messenger does, a little message to your body to create an immune response to a spike protein [of the COVID-19 virus],” she said.
Johnson & Johnson uses something called adenovirus technology. (Adenoviruses cause the common cold.) It’s “a similar but different mechanism to get your body to respond using a dummy version of a common virus that causes the cold,” Patel said. The vaccine technologies use different methods to accomplish the same goal. “It’s really fooling the body into thinking that you’re exposed to the coronavirus, so that when you’re really exposed to the coronavirus, that immune system is ready to kick in,” Patel said.
How effective is the Johnson & Johnson vaccine?
The FDA set a threshold that a COVID-19 vaccine needed to be at least 50 percent effective to be approved. It confirmed that 28 days after inoculation, Johnson & Johnson’s single-dose vaccine is 66 percent effective overall at preventing moderate to severe COVID-19. That number is significantly lower than the nearly 95 percent efficacy rates of the two-dose vaccines by Pfizer and Moderna.
But Patel said it’s apples and oranges and bananas to compare them to each other. “All three of these manufacturers — Pfizer, Moderna and Johnson & Johnson — conducted their trials at different times in different parts of the world,” she said.
For example, unlike the clinical trials for the Pfizer and Moderna vaccines, the Johnson & Johnson trial was performed at a time when the South African variant was present. The company found that its COVID vaccine drops to 57 percent effectiveness against that variant, also called B.1.351. Studies have also shown a drop in the effectiveness of the Pfizer and Moderna vaccines against the South African variant, and both vaccine makers are testing a third booster shot to account for evolving virus mutations.
All three vaccines are also more effective than the seasonal flu vaccine. “Any of these efficacy rates, no matter how you look at them, are much higher than any of the efficacy rates we’ve seen for viral vaccines in the past,” Patel said. The Centers for Disease Control and Prevention website says a seasonal flu vaccination can be anywhere between 40 and 60 percent effective depending on the season.
Patel said that while it’s tempting to compare efficacy numbers, “all three of the currently authorized vaccines prevent death, prevent severe hospitalizations, and that’s what really matters.”
Given the three COVID-19 vaccines currently available, Patel urged that Americans not wait to receive a more effective one. “Any vaccine you’re getting today is going to be a completely appropriate choice to protect you from what we need to do and to get life back to normal.”
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