Already criticized by some for being too noisy, the vuvuzela could also be spreading colds and flu germs, according to a London doctor.
The vuvuzela, a long plastic horn as common as uncomfortable seats at soccer matches in South Africa, is just about the most popular item in the country with the World Cup only one day away.
But with the flu season in South Africa in full swing, Dr. Ruth McNerney of the London School of Hygiene and Tropical Medicine told The Associated Press that the instrument could cause health issues.
"Vuvuzelas have the potential to spread colds and flu as a lot of breath goes through the vuvuzela," McNerney said, adding that they can infect others on a greater scale than coughing or shouting.
McNerney was involved in a recent study of eight healthy volunteers who blew the vuvuzela in order to measure what comes out at the other end. They found that tiny droplets which can carry flu and cold germs were formed at the bottom of a vuvuzela.
Those particles are small enough to stay suspended in the air for hours, and can enter into the airways of a person's lungs, McNerney said by telephone.
"For ethical reasons, we have not tested sick people yet as we need special permission and a secure room to test sick people in," McNerney said. "But it is evident that the potential of a vuvuzela spreading colds and flu exists."
Dr. Maggi Soer of the Department of Communication Pathology at the University of Pretoria agreed that it could be harmful, especially because people often share vuvuzelas by passing it along to each other to blow.
"For me that is not a healthy principle," Soer said.
But Soer was also concerned about another potential danger: hearing loss.
In a separate study done by Prof. James Hall and Dr. Dirk Koekemoer at the University of Pretoria, it was found that vuvuzelas can have negative effects on people's ear drums when they are exposed to the sound for a certain time period.
Soer, who was present when the study was done and is knowledgeable of the findings, gave some simple advice on how to avoid any danger.
"Wear earplugs to the games," she said. "Either buy them at a pharmacy or make them yourselves and take it with you to the soccer games."
Despite the health risks, some soccer fans aren't at all concerned.
"I am not worried," said Matthew M'Crystal, a 24-year-old law student. "Anyway, it won't kill us."
Others, however, don't want to chance it.
"We have to take certain precautions to avoid spreading diseases with the vuvuzelas," said Shireen Morgan, a local housewife and mother of two who said she allows her children to blow vuvuzelas, but explained that she "gives them medicine" to keep them from getting ill.
As for the fans in South Africa just for the World Cup, it's going to take more than the threat of a cold to keep them from taking part in the local phenomenon.
"I could have died in Mexico," said Ricardo Avila, a 56-year-old soccer fan visiting South Africa for the tournament. "So no, it does not bother me."