Denmark's Jonas Vingegaard, left, and teammate Matteo Jorgenson of the U.S. wear face masks to protect themselves from COVID-19 prior to the start of the 14th stage of the Tour de France cycling race, in Pau, France, July 13, 2024. DANIEL COLE/AP

Thousands of athletes and spectators from around the world have descended on Paris for the looming 2024 Summer Olympics. They've brought with them the potential for a COVID-19 outbreak to spread within the tightly confined Games atmosphere.

Officials expect Paris to receive as many as 15 million visitors, including 2 million tourists from abroad, during the Games.

Dr. Céline Gounder, CBS News medical contributor and editor-at-large for public health at KFF Health News, said Wednesday on "CBS Mornings" that a current spike in cases across the U.S. is likely due to the coronavirus continuing to mutate, and to vaccinations only preventing infection reliably for several months, though they continue to protect from severe illness for much longer, "which is why people are not getting sick the way they were early in the pandemic."

That underlying vaccination success may be helping to allay fears in Paris, where, despite a growing spate of early Olympic COVID-19 cases, disruptive infections at the recent Tour de France, the surge in infections in the U.S. and elsewhere and most antiviral international travel measures being long since lifted, Games organizers don't appear too worried.

COVID at the Tour de France
France experienced a new wave of coronavirus cases in the general population in June, and the virus has hit some major sporting events more recently — including the Tour de France, which took place from the end of June until July 21.

Tour authorities established no official protocols in advance to deal with a flareup of the well-known pathogen, which delayed their reaction after the first cases among riders cropped up early during the three-week race.

It took the event's main organizer, the Amaury Sport Organization, until July 14 to ask journalists to wear face masks during interactions with riders and support teams.

Without any real COVID safety protocols in place, individual athletes and teams were left to develop their own strategies to deal with the virus, and responses varied widely.

While at least four athletes who tested positive pulled out of the race, others continued to compete, drawing complaints from some of their competitors.

Early Olympic COVID cases
There have already been positive tests at some of the Olympic training sites. In the most recent cases, national team chief Anna Meares confirmed Wednesday that five of Australia's women's water polo players had tested positive for COVID-19.

"There is training this afternoon and, again, if those five athletes are feeling well enough to train, they will, and they are following all the protocols that we have," Meares said at a news conference in Paris. "I can confirm that the whole of the water polo team has been tested as well."

Meares said the infected polo players had started wearing face masks and were isolating from other team members when not actively training.

"They're not going into the high-volume areas of the allotment, like the gym and the performance pantry, and more broadly, we have our respiratory illnesses protocol in place," she said.

Several Belgian athletes delayed their departure for Paris after receiving positive tests.

The French Judo Federation had previously cut short its men's team's pre-Olympic training camp after a participant was diagnosed with COVID-19, and French soccer player Selma Bacha and track-and-field athlete Cyréna Samba-Mylena have also tested positive.

After positive tests during the French national swimming championship, the country's Olympic swimming team implemented stricter precautions during its July training session.

Given the pre-opening ceremony cases and the recent history at the Tour de France, the focus has turned sharply toward the fast-approaching Games.

Some 10,500 athletes are due in the French capital, and organizers know that along with the spirit of sportsmanship, they bring with them the potential for a major outbreak in the Olympic Village, which will be home to more than 14,000 athletes and accompanying team members.

But organizers appear relatively unfazed.

"For now, nothing has been put into place by the organizing committee," André-Pierre Goubert, the director of Olympics and high performance sport at the National French Olympic and Sport Committee (CNOSF), recently told the French newspaper Le Monde. "We recommended that the delegations test their athletes before coming to the Olympic Village, using their own medical teams."

Face masks are not required inside the Olympic Village, but hand sanitizer is available in its clinics and restaurants.

Public health officials in France admit an outbreak is possible and they've said athletes, support teams and tourists should be prudent, but not worried.

Games organizers have said they're keeping an eye on the situation and have promised to work closely with the French Health Ministry and the nation's public health authority to monitor cases over the course of the Olympic and Paralympic Games.


Australian Olympic athletes are seen wearing protective face masks in the Olympic Village ahead of the Paris 2024 Summer Games, July 23, 2024. BENOIT TESSIER/REUTERS


Participants in the Paris 2024 Olympic and Paralympic games walk in front of the cafeteria of the Olympic Village, in Saint-Denis, northern Paris, July 22, 2024, ahead of the opening ceremony. MICHEL EULER/POOL/AFP/GETTY