Over the weekend, the FDA granted emergency use authorization to Johnson & Johnson’s single-dose COVID-19 vaccine.

Alex Gorsky, CEO of Johnson & Johnson, told TODAY that as of this morning, the newly approved vaccine is “on trucks […] within the next 24 to 48 hours, Americans should start receiving shots in arms.”

A senior Biden administration official told CNN that about 3.9 million doses of the vaccine will soon be distributed to states, tribes, territories and health centers, according to CNN.

Adding a third vaccine to the fight against the coronavirus comes at a critical time. Top health experts fear that highly contagious variants of COVID-19 are poised to sweep through the country.

A new vaccine in the fight against COVID-19

The Johnson & Johnson vaccine differs from the Moderna and Pfizer-BioNTech vaccines. The J&J shot is a one-dose vaccine. Recipients won’t have to return for a follow-up appointment to receive a booster shot several weeks later like they do with the Moderna and Pfizer shots.

It can also be stored in a refrigerator, instead of a freezer. Experts say that makes the J&J vaccine easier to transport and an easy choice for mobile vaccinations.

The Johnson & Johnson vaccine has a 72% efficacy rate against mild to severe/critical disease in the U.S. It’s about 85% effective against severe forms of the disease.

The Pfizer and Moderna vaccines have efficacy rates of about 95%.

Health experts like Dr. Fauci say you shouldn’t be worried about the seemingly lower numbers. The J&J vaccine was tested later than the other two shots, when infections were already surging and new variant strains were spreading through the country.

In clinical trials, the Johnson & Johnson vaccine still proved safe and effective, completely preventing hospitalization and death.

Plans to test the vaccine in infants and pregnant women

Before the first Johnson & Johnson shot has been administered, the company is already planning new clinical trials that involve newborns, infants, and pregnant women.

In the paperwork the company submitted to the FDA for review, they briefly outlined the next phases of their clinical studies.

First, the company plans to introduce a study for children between the ages of 12 and 18. Then, they plan to open a trial for all children under the age of 18.

The next trial will involve pregnant women and their infants, and the fourth planned clinical study will include immunocompromised individuals.

How does it work?

The Johnson & Johnson team behind the vaccine published their original clinical trial results in the New England Journal of Medicine last month.

Doctors divided patients into two groups based on their ages: 18 to 55 and 65 and older. All patients received a high or low dose of the vaccine or a placebo.

After 28 days, nearly all of the volunteers who received the vaccine went on to generate antibodies to help defend against the virus. After 57 days, every volunteer had detectable antibodies, regardless of their dosage or age.

Will the COVID-19 vaccine become mandatory in America?

As more vaccines are approved and become easily accessible, many parents are wondering if the vaccine will become mandatory in America.

That’s unlikely, according to Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases.

Dr. Fauci told Newsweek that he doesn’t expect the federal government will issue a mandate regarding the vaccine.

He did acknowledge that in the future, businesses, organizations, and schools may choose to make the vaccine mandatory for employees, members, or students.

He likened the situation to how many hospitals require employees to be vaccinated against influenza and Hepatitis B.

“Here at the NIH [National Institutes of Health], I would not be allowed to see patients if I didn’t get vaccinated every year with flu and get vaccinated once with Hepatitis [B],” explained Dr. Fauci. “I have to get certified every year…if I didn’t, I couldn’t see patients.”

Similarly, it’s possible that school systems may choose to require their students to be vaccinated. But that order would come from the individual school systems, not from the federal government.

Those scenarios are a long way off, though.

While we wait for a full-pediatric vaccine, let’s continue to keep our families safe by maintaining social distancing, wearing our masks, and washing our hands frequently.