What happened

For the third trading day in a row, shares of Carnival Corporation (CCL 0.06%) and Norwegian Cruise Line Holdings (NCLH 0.64%) are on the rise, up 4.1% and 4.2%, respectively, as of 11 a.m. EDT.

And it's not just cruise stocks moving higher. Movie theater chain AMC Entertainment (AMC -5.41%) is also notching its third straight day of share-price gains -- up 2.6% -- and it's all because of COVID-19. Or more precisely, it's because of the answer to COVID-19: the Comirnaty vaccine developed by Pfizer and BioNTech.

Small audience cheering in a movie theater.

Image source: Getty Images.

So what

Stocks tied to the tourism industry began moving higher on Friday in anticipation of a decision from the U.S. Food and Drug Administration fully approving Pfizer and BioNTech's coronavirus vaccine for prevention of COVID-19 infection in patients aged 16 and over.

That decision became official on Monday, and with it came stock-price gains of 4.2% for Carnival, 4.3% for Norwegian, and 6.9% for AMC. Today's moves higher are simply a continuation of investors' reaction to the positive FDA news.

Now what

Up until now, part of the reason that some people have hesitated to take the vaccine is because it was technically approved only for Emergency Use Authorization (EUA). That was a judgment call on the FDA's part, which essentially meant that in its opinion, people were safer taking the vaccine than not taking it (and risking infection with COVID-19).

Full FDA approval, on the other hand, means people now aren't just saf-er taking the vaccine, but that they're safe, period (at least within the age group covered). That could be enough to boost immunization levels in the U.S. beyond their current 57% rate toward levels that will reassure consumers that they can safely take a cruise, or go see a movie, without undue risk of falling seriously ill from the virus.  

As reasons to be more optimistic about cruise line and movie theater stocks go, I think it's a pretty good one.