What happened

Investors' holiday cheer received a rude interruption on Thanksgiving Day 2021: In South Africa, a new coronavirus variant is rising -- and it's terrifying investors with fears of a prolonged cruise industry recession.

Shares of Carnival Corporation (NYSE:CCL) (NYSE:CUK), Royal Caribbean (NYSE:RCL), and Norwegian Cruise Line Holdings (NYSE:NCLH) sank in quick succession as of 10:10 a.m. ET today, falling 10%, 10.2%, and 10.3%, respectively.

Collage showing a cruise ship, a person in a face mask and coronavirus particles.

Image source: Getty Images.

So what

So here's the news in a nutshell: On Thursday, South African Minister of Health Joe Phaahla announced that an investigation of "cluster outbreaks" of COVID-19 in parts of the country has found a new variant of the coronavirus -- dubbed B.1.1.529.  

Initially detected in South Africa, reports CNN, the virus has also popped up in neighboring Botswana and in Hong Kong (carried there apparently by a traveler from South Africa). According to CNN, scientists are saying that the new variant has "an unusually high number of mutations," including "more than 30 in the key spike protein" alone -- the key that coronavirus uses to unlock a victim's cells. 

Responding quickly to the news, the United Kingdom banned incoming flights from South Africa, Namibia, Lesotho, Botswana, Eswatini, and Zimbabwe. South Africa's Center for Epidemic Response and Innovation is urging citizens to "avoid super spreading events."

Now what

Suffice it to say that cramming thousands of tourists at a time aboard a ship at sea could be considered such a "super spreading event," and so it's likely this new variant will have a depressing effect upon any cruise activity involving South Africa. The bigger story, though, is that experience has shown that coronavirus variants that appear in one country don't stay there for long -- but spread, and become global events in a matter of months or even weeks.

In short, if investors in the cruise industry are feeling nervous today, there's good reason for that. In recent months, the cruise industry seemed to have finally found its footing, with multiple operators predicting that significant portions of their fleets would soon be operating again at something approaching full capacity. Analysts who follow the industry had even predicted that 2022 would be the year that Carnival and Royal Caribbean turned profitable again, and that Norwegian Cruise would follow suit in 2023.  

Now, all that good news has been turned on its head, and everyone's scared again.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.