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 per cent 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 per cent to 40 per cent lower odds of getting acute lymphoblastic leukemia.
Lymphoblastic leukemia 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.
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.”