Why Johnson & Johnson's COVID-19 vaccine will help in the fight to end the pandemic

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.