BATON ROUGE - Millions of doses of the Johnson & Johnson COVID-19 vaccine are being distributed nationwide this week with 37,900 of those going to Louisiana hospitals.

First it was Pfizer, then Moderna, now it's Johnson & Johnson. Authorization of the third coronavirus vaccine comes nearly one year after Louisiana saw its first confirmed case on March 9, 2020.

The Food and Drug Administration authorized the vaccine on Saturday, and the Center for Disease Control and Prevention mirrored that decision the following day. By Sunday night, nearly four million doses began shipping out.

Of those millions of doses, Louisiana hospitals are prepping to receive 37,900 of them, according to the CDC. 

Unlike Pfizer and Moderna, the Johnson & Johnson COVID vaccine is given in a single dose, making it easier to schedule an appointment without needing a follow-up. The new vaccine is also more durable, lasting up to three months in the refrigerator, whereas the other vaccines must be stored at very cold temperatures.

As of Monday, nearly 8% of the nation has been vaccinated, including Dr. Anthony Fauci, Director of the National Institute of Allergies and Infectious Diseases. Dr. Fauci reassured that the new vaccine is worthwhile despite concerns.

"These are three highly efficacious vaccines. I can tell you. I have been fully vaccinated with one that was available, it was the Moderna. If I were not vaccinated now and I had a choice of getting a J & J vaccine now or waiting for another vaccine, I would take whatever vaccine would be available to me," Dr. Fauci said.

The Johnson & Johnson vaccine is 85% effective at preventing severe illness, while Pfizer is 95% and Moderna is 94.1%. All three vaccines are 100% effective at preventing hospitalization and death 28 days after receiving the full dose. 

"There's a lot being talked about with the different percentages, with these vaccines against the coronavirus. When all of this first began, the FDA indicated that an efficacy of 40% would be good enough to get these vaccines approved for emergency use," said Dr. Sandra Kemmerly, system medical director with Ochsner.

Though the percentages differ, physicians say this is not something to worry about.

"All of these vaccines have shown in the clinical trials to prevent death due to COVID. So we want to make sure we prevent death and serious disease, and all of the vaccines have been shown to be effective to do that. We want to be sure that anybody that's offered a vaccine takes whatever is available to them," said Dr. Katherine Baumgarten, Ochsner's director of Infection Control and Prevention.

Health experts say because the Johnson & Johnson vaccine is a single dose, it can offer more protection faster than the other two vaccines, which both require two shots four weeks apart.