News Story
Some vaccines may protect children against cancer: study
By Genevra Pittman at Reuters Health
Children who have had certain vaccines may be
less likely to develop childhood cancer, especially one type of
leukemia, according to a U.S. study.
The findings, published in The Journal of Pediatrics, showed that
children born in areas where most children had been vaccinated for
hepatitis B had about 20 percent lower odds of all types of
childhood cancer than those born in areas where fewer were
vaccinated.
In particular, those born in areas with high use both of polio
vaccine and a vaccine series that included hepatitis B and polio,
among other diseases, had 30 percent to 40 percent lower odds of
getting acute lymphoblastic leukemia -- a type of leukemia that is
most common in childhood.
Michael Scheurer, from the Baylor College of Medicine in Houston,
Texas, and one of the study authors, warned that despite the
apparent relationship, which should become clearer with future
research, it's not a situation of "get your kids vaccinated and they
won't get cancer."
Previous studies have shown mixed results. One theory is that some
common infections may increase a child's risk of leukemia because of
the effect they have on the developing immune system.
Vaccinations, theoretically, should then cut down on that cancer
risk -- unless the vaccine itself closely enough mimics a natural
infection.
Aiming to see if children born in areas where most children were
vaccinated were more or less likely to get cancer than those born in
areas with lower vaccination rates, Scheurer and his colleagues used
data on all cancer diagnoses in the U.S. state of Texas to identify
2,800 cases of childhood cancer diagnosed in 1995-2006 among 2 to
17-year-olds who had been born in Texas.
For each child diagnosed with cancer, the researchers found four
others of the same age and gender who had not. Then, they compared
how many of the children with or without cancer had been born in
counties with high vaccination rates.
According to Scheurer, the strongest finding was a decreased risk of
leukemia in areas with high vaccination rates for hepatitis B and
polio -- which is also where most of the previous childhood cancer
research has shown a benefit for vaccination.
Scheurer added that the study was timely because it pointed out an
added benefit of getting routine childhood vaccinations --
particularly because it coincides with recent news that British
researcher Andrew Wakefield faked some evidence that supposedly
showed a link between vaccines and autism.
"People can take a step back and really look at the benefit that
vaccines provide -- not just for the infectious diseases they were
intended to prevent," he said.
"Now, there appears to be some other added benefit."