A children's party with cake, candy and a communicable virus. Sounds like fun, right?

On Tuesday, California health officials warned parents against intentionally exposing their children to the measles virus at get-togethers nicknamed "measles parties." The thought is that by exposing unvaccinated children to the virus it would help them develop natural immunity.

The concept dates to the 1980s, when parents held chicken pox parties. Though chicken pox is less serious than measles, it is still highly contagious, and it was considered safer for children to get it over with since the illness can be deadly in adulthood. Chicken pox parties became less common after a vaccine for the virus won FDA approval 1995.

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When it comes to measles, "the idea is that maybe it's somehow safer, more effective, more natural to expose your kids to the real live virus as opposed to getting the vaccination," Dr. Tara Narula, CBS medical contributor and assistant professor of cardiology at Hofstra University, told CBS News. "So now we're hearing rumors of this occurring with measles, and it's kind of inconceivable that this actually occurs and it's quite dangerous, so I think people really need to understand that this isn't just a party."

Officials in Marin County, California, haven't officially confirmed that such parties are taking place. However, a recent show on the KQED radio station in the Bay Area made clear that the concept is on the minds of parents. A mother of two unvaccinated kids called in to the station to say a friend offered to help her expose them to the virus.

"Supposedly, the mother refused," said Narula. "We really don't have a lot more information. But despite that, the California Department of Health is issuing that warning."

The state's health department "strongly recommends against the intentional exposure of children to measles," the agency said in a statement. "It unnecessarily places the exposed children at potentially grave risk and could contribute to further spread."

In the current U.S. measles outbreak, at least 166 people have been infected in 18 states and the District of Columbia. More than 100 of those cases occurred in California.

Narula believes parents do not understand how serious a case of measles can be. The measles virus has a 90-percent transmission rate, and when a child catches it, the risk of complications is high. One in 20 children with measles will develop pneumonia. Encephalitis, or brain swelling, occurs in at least 1 in 1,000 patients, and it can have long-term consequences that include cognitive and mental impairment, hearing loss and blindness. Approximately 1 or 2 out of very 1,000 people who get measles will die.

Complications associated with the vaccine are uncommon and generally mild. They include seizures (1 in 3,000 people) and a drop in your platelet blood count (1 in 30,000), Narula said.

"So logically, when you look at the numbers again, the complication rate from the vaccine is much, much lower than the complication from the actual virus," said Narula. "I think that people haven't really seen the measles; they don't really understand how bad it can be. They think of it as just a rash or maybe some sort of cold, cough and flu-like symptoms. Anyone who has children, you hate when your child gets sick, you feel extremely helpless."