Moderna stock closed higher Tuesday even after the Food and Drug Administration held off recommending a booster dose of the company's Covid shot.

Real-world studies show Moderna's original two-dose regimen is less effective against the delta variant, the FDA said in a briefing document. But other studies suggest the vaccine remains protective.

"Overall, data indicate that currently U.S.-licensed or authorized Covid-19 vaccines still afford protection against severe Covid-19 disease and death in the United States," the agency said in the document.

In response, Moderna stock jumped 2% to 311.13 on today's stock market.

Moderna Stock: Booster Shot On Deck

The FDA's Vaccines and Related Biological Products Advisory Committee is scheduled to meet Thursday to discuss the merits of offering a Moderna booster shot. On Friday, the committee will tackle the same question for Johnson & Johnson's single-jab vaccine.

The advisory committee's recommendation is nonbinding, but the FDA often follows it. The document offers a glimpse into how the agency might view Moderna's booster. On Sept. 1, Moderna asked the FDA to authorize a third shot of its vaccine at a half dosage six months following the second shot.

If successful at the FDA, the matter will head to a similar advisory committee at the Centers for Disease Control and Prevention. Then, it will go to the full CDC. An authorization could help prod Moderna stock again.

Last month, the FDA and CDC signed off on a booster shot of the Pfizer and BioNTech vaccine. That shot is now available to older Americans, people with underlying conditions that put them at risk of severe Covid and workers at risk due to employment.

Moderna stock popped more than 3% the day following the Pfizer-BioNTech win as investors hoped the agencies would take the same step for the other messenger RNA vaccine.

Shares Under Pressure

Since then, Moderna stock has fallen precipitously, alongside other vaccine makers. Shares crossed below their 50-day moving average on Sept. 28, according to MarketSmith.com.

Vaccine stocks continued to fall after Merck said its Ridgeback Biotherapeutics-partnered pill, molnupiravir, cut the risk of hospitalization or death by half for people with mild-to-moderate Covid cases.

Despite its recent challenges, Moderna stock still holds a Relative Strength Rating of 98, IBD Digital shows. This puts the stock's performance in the top 2% of all stocks over the past 12 months.

Follow Allison Gatlin on Twitter at @IBD_AGatlin.