A disturbing new trend is reportedly growing that has infectious disease experts worried: "swine flu parties."

The disease-swapping soirees are being hosted by parents who intentionally mix their children with those infected with the H1N1 virus.

The idea, the parents believe, is that by allowing their child to get ill with the virus now, while it causes mild illness, their children will be immune if the virus were ever to change to become more virulent. The trend first made headlines in Britain and now public health experts are worried that, like the flu, the idea could spread.

Dr. Michael Gardam, director of infection, prevention and control with the University Health Network in Toronto tells Canada AM "flu flings" are a bad idea for a number of reasons.

"First off, not all people have mild disease from H1N1. A small percentage develop serious disease. Can you imagine being the parent who intentionally gets their kid infected only to have child end up in the ICU later?" he said Friday.

Second of all, he said, even if parents think they can control when their child gets sick with these parties, as some parents did with "chicken pox parties" in previous generations, parents can't control how far the infection will spread.

"Unlike chicken pox parties, where typically, the adults have had the infection already, in this case, your kid could get infected and then come home and give it to everybody else in the family," said Gardam.

Gardam added there is no reason to believe that everybody needs to develop immunity to this virus. "Even in a pandemic, the majority of the population isn't going to get sick," he noted.

Infectious disease experts say there is still a lot left to understand about H1N1, such as who it infects, what allows it to spread, and whether it's changing. For now, Canadian officials experts will be watching how the virus reacts with the warmer weather and the end of school.

The focus is now on developing and mass-producing a vaccine, Gardam says. Until then, people should avoid contracting the virus as much as possible.

"We're looking at the end of October when we'll have a vaccine available," he said.

"All of our strategies are based on slowing things down until the vaccine comes. This [flu party trend] is the absolute opposite of what we're trying to do."