Early childhood vaccine reduces leukemia risk

Dr Jopling found this great article put out by the AAP-- SAN FRANCISCO, May 21 (UPI) -- The Haemophilus influenzae Type b, or Hib, vaccine helps prevent the most common type of childhood cancer, in addition to its primary mission of preventing ear infections and meningitis that are caused by the Hib bacterium, according to a new study. Researchers now believe the vaccine prevents acute lymphoblastic leukemia because Hib infections can increase immune system reactions that turn relatively common "pre-leukemia" blood cells into cancer cells. This is prevented because the infections don't happen once all four doses of the vaccine have been administered to children.

"These experiments help explain why the incidence of leukemia has been dramatically reduced since the advent of regular vaccinations during infancy," said Markus Müschen, MD, PhD, a professor of laboratory medicine at University of California-San Francisco, in a press release. "Hib and other childhood infections can cause recurrent and vehement immune responses, which we have found could lead to leukemia, but infants that have received vaccines are largely protected and acquire long-term immunity through very mild immune reactions." With this knowledge in hand, researchers now are looking at other other vaccines to see if the infections they prevent are connected to the way other cancers begin forming in the body. "The study provides mechanistic support for the hypothesis that infection or inflammation promotes the evolution of childhood leukemia and that the timing of common infections in early life is critical," said Mel F. Greaves, MD, PhD, professor of cell biology at the Institute of Cancer Research in London.