A specialist in infectious diseases in children says she is shocked by reports that some parents in the U.S. are trading chickenpox-contaminated lollipops in an effort to naturally immunize their children, rather than get the chickenpox vaccine.

Canadian Paediatric Society member Dr. Marina Salvadori says she is baffled over why anyone would want to risk their children's health in that way.

"It's not safe for your child and it's totally inappropriate," she said in a phone interview.

A number of news outlets in the U.S. reported this week on a Facebook group called "Find a Pox Party in Your Area." The group consisted of parents who were willing to ship chickenpox-contaminated items around the country to other parents wanting to "naturally" immunize their children.

Some had vials of infected spit to sell, while others offered candy and lollipops that their sick kids had sucked on.

A U.S. federal prosecutor reacted to the reports by pointing out that sending a known contagion through the mail is a federal offence. The page, which had about 900 Facebook "Likes" at one point, was quickly removed. But the practice likely continues elsewhere.

Dr. Salvadori, who works at London Health Sciences Centre, says the idea of asking your child to drink the spit of another child or lick their used lollipop is not only absurd, it puts them at risk of all kinds of germs.

"They are potentially exposing kids to pneumococcus, meningococcus, streptococcus A… Your mouth is a pond, a swamp, it's full of bad things," said Salvadori.

The chickenpox vaccine, on the other hand, is safe, she says. One in seven might develop a fever after getting the shot, and some will develop a mild rash, but most children have no reactions. And recent research suggests that two doses of the vaccine offer long-lasting immunity.

"So to say ‘I'd rather expose them to all of those things rather than the well-refined, very well-regulated product of a vaccine' sounds to me a bit absurd," Salvadori says.

She also wonders whether the lollipop idea would even work. Chickenpox spreads much like the flu -- from a virus that travels through the air; it doesn't transmit very well off surfaces.

"The lollipop method has never been shown to be effective or safe," she says.

Smallpox started 'pox parties' idea 

It's interesting to note that deliberately infecting children with viruses is nothing new. "Pox parties" actually started in the days of smallpox, when parents discovered that exposing their children briefly to people who were already infected helped to protect them from getting sick.

Salvadori says strange as it might sound, the method can actually work and is "scientifically valid." Pox parties operate on the same concept as a vaccine: a small amount of exposure to confer lifelong immunity.

"So there is a scientific premise to getting a very small exposure in the air," she says.

But the only way it's safe is if the child is exposed to just a small amount of the virus, because the more chickenpox virus that one breathes in, the sicker they will become. That's why a child who's infected at school typically has a milder illness than a child infected while living in the same house as a sick sibling.

The problem, of course, is that it's difficult to control how much infected air your child breathes. And then, every child's immune system is different, so some might not show any reaction while other kids might develop full-blown, serious illnesses.

"Even kids who get chickenpox naturally in that way are still prone to complications," Salvadori says.

Chickenpox can be fatal in some

While most adults in Canada who had chickenpox as kids remember it as an illness that causes a flu-like illness, spots and a week of bedrest, chickenpox can lead to severe complications.

Before the chickenpox vaccine was introduced in Canada almost a decade ago, 5,000 children a year had to be hospitalized for chickenpox infections. Some developed brain infections, others blood infections and others pneumonia.

Dr. Salvadori also notes the chickenpox "spots" can act as little doorways for all kinds of bacteria, including group A strep, which is a cause of flesh-eating disease.

Some children pick up strep A and then a staph infection that goes into their bones.

"One of my first patients – one of the cases that made me want to become an infectious diseases doctor – was seeing a little girl get chickenpox and then lose her leg to amputation," Salvadori says.

The virus that causes chickenpox never leaves the body and can redevelop much later in life into shingles, a condition that can cause severe nerve pain, which, in some cases, lasts the rest of one's life.

"So chickenpox can case a wide spectrum of disease and it can make people really sick and even cause death," she says.

One report noted that some users of the pox party Facebook page were also looking for samples of measles and mumps, because they hadn't vaccinated their children against those infections either.

Salvadori says she would never recommend anyone deliberately infect themselves or their children with measles since that's an infection that tends to cause severe illness. About 1 in 1,000 infected children will develop encephalitis, while one in 100,000 will develop a degenerative disease called SSPE, or subacute sclerosing panencephalitis.

SSPE brings on dementia in a child and can even affect kids who appear to have fully recovered from measles, Salvadori says.

"It's like they get Alzheimer's at 6 or 7, and they completely degenerate and die within three or four years," she says.

"I've seen two patients with that and it's absolutely tragic."

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