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The Johnson & Johnson COVID-19 vaccine will be the third vaccine available in the United States. Niels Wenstedt/BSR Agency/Getty Images
  • People in the United States will soon have access to three coronavirus vaccines.
  • The FDA has authorized the Johnson & Johnson COVID-19 vaccine for emergency use.
  • The decision comes one day after a key advisory group voted to give emergency authorization for the single-dose vaccine.

The Food and Drug Administration (FDA) has authorized the use of the single-dose COVID-19 vaccine made by Johnson & Johnson (J&J).

This emergency use authorization (EUA) was given one day after an advisory group recommended that the FDA allow Johnson & Johnson’s coronavirus vaccine to be given people 18 and older.

The Vaccines and Related Biological Products Advisory Committee voted unanimously 22-0 in favor of the EUA on February 26.

The vote came after the panel of independent scientific experts, infectious disease doctors, and statisticians spent much of the day reviewing data from Johnson & Johnson phase 3 clinical trial.

The single-dose vaccine is made by J&J’s vaccine division, Janssen Pharmaceuticals. It’s also “fridge stable,” which means it can be shipped and stored at standard refrigerator temperatures.

“This is going to allow for easier delivery to different sites in the country and enable a greater proportion of the country to be vaccinated,” said Dr. Jarod Fox, an infectious disease physician at Orlando Health, who was not part of the advisory committee.

Both the Pfizer-BioNTech and Moderna-NIAID coronavirus vaccines need to be stored in ultracold freezers until being thawed prior to use.

An analysis of the J&J data by FDA scientists found that this vaccine offers strong protection against severe COVID-19, although it showed a lower overall effectiveness.

The scientists also identified “no specific safety concerns” that would prevent the vaccine from receiving emergency authorization.

The FDA doesn’t need to follow the recommendation of the advisory group, but it usually does.

This new EUA will give people in the United States access to a third coronavirus vaccine, although the J&J vaccine is expected to have limited availability in the beginning.

In the analysis, FDA scientists confirmed that the vaccine had an effectiveness of about 66 percent against moderate-to-severe COVID-19 at least 14 days after vaccination.

Effectiveness against severe COVID-19 was about 85 percent 28 days after vaccination. This was similar across all racial and age groups.

However, effectiveness was lower for people 60 and older with certain underlying health conditions such as heart disease and diabetes.

Fox said this is concerning because this group is “at higher risk for having severe or critical illness with the coronavirus.”

However, “it is good to see that the vaccine has moderate efficacy in this group — it’s just not as high as in the 18-to-59 group,” Fox said.

Efficacy is a measure of how well vaccines work during a clinical trial. Real-world vaccine effectiveness may be lower due to a number of factors.

J&J tested its vaccine in a phase 3 clinical trial involving almost 44,000 adults in the United States, Brazil, and South Africa.

Overall efficacy varied from region to region. It was 72 percent in the United States and about 68 percent in Brazil.

Efficacy dropped to 64 percent in South Africa, where a new coronavirus variant emerged in the fall and is now the dominant form in that country.

The AstraZeneca and Novavax coronavirus vaccines also showed lower efficacy in South Africa.

However, the J&J vaccine had similar effectiveness against severe COVID-19 in all regions: about 86 percent in the United States, 82 percent in South Africa, and 88 percent in Brazil.

This means that even if a vaccinated person gets the coronavirus, they are much less likely to be hospitalized or die from COVID-19.

The FDA’s analysis showed that protection offered by the vaccine began to show up 14 days after vaccination.

By 28 days after vaccination, there were no cases of hospitalizations or deaths in the vaccinated group, compared to 16 hospitalizations and 7 deaths in the group that received the inactive placebo.

The overall efficacy of the J&J vaccine was lower than the Pfizer-BioNTech and Moderna-NIAID vaccines.

Experts caution that it’s difficult to make direct comparisons because the vaccines were tested under different conditions and at different times.

As with the other coronavirus vaccines that have been authorized, the main side effects of the J&J vaccine were pain at the site of the injection, headache, fatigue, and muscle pain.

Dr. Macaya Douoguih, head of clinical development and medical affairs for Janssen, told the advisory committee on Friday that one person taking part in the study in South Africa developed a severe allergic reaction, known as anaphylaxis, after receiving the vaccine.

A small number of cases of anaphylaxis have been reported after receiving the Pfizer/BioNTech and Moderna/NIAID coronavirus vaccines.

“Anaphylaxis does occur, though rarely, and there are no safety signals for any serious adverse events,” Tom Shimabukuro, from the Centers for Disease Control and Prevention (CDC), told the panel.

Because of this potential side effect, the CDC recommends that people be monitored for 15 minutes after their vaccination, and for 30 minutes for people with a history of allergic reactions.

Blood clot-related conditions occurred in 15 people who received the J&J vaccine and 10 people who received the placebo. In the documents for the advisory meeting, the FDA said it will recommend ongoing monitoring for similar cases if the vaccine is authorized.

If the FDA issues an emergency authorization of the J&J vaccine, it won’t increase the vaccine supply in the United States right away.

The Biden administration expects that only 2 million doses of the vaccine will be shipped during the first week after authorization, with 20 million available by the end of March, the Associated Press reported.

The emergency authorization of a third vaccine, one with a lower overall efficacy, may cause some people in line for vaccination to hold out for a specific vaccine.

But Fox said the J&J vaccine still exceeds the 50 percent efficacy threshold set by the FDA last year for coronavirus vaccines. The country may also need all three vaccines in order to stop the pandemic.

“If everyone was vaccinated in some fashion, we would be in a good place,” he said. “So I would rather everyone gets some vaccine rather than waiting for a particular vaccine that may be slightly more effective.”

He also reminds people that until the majority of the country is vaccinated, we will need to continue to take other measures — such as wearing masks, physical distancing and hand washing — to slow the spread of the coronavirus.

“That’s going to continue to be important, because none of these vaccines are 100 percent effective,” he said. “If we want to prevent transmission, we’ve got to do all of these things, including vaccination.”