Can the Chickenpox Protect Patients Against Glioma?

Any parent of a child who has had the chickenpox will likely be quick to explain that it was not a pleasant experience. However, according to a recent study, the bumps and itching that the virus brings may offer a long-term benefit: protection against glioma.

The study, conducted by more than a dozen top research institutions across the United States, Canada, Sweden and Israel, found that a history of the chickenpox was associated with a 21 percent lower risk of glioma. This correlation was particularly strong with the chickenpox’s protective effect against high-grade gliomas.

Using data from the Glioma International Case-Control Study (GICC), researchers evaluated 4,533 cases and 4,171 controls from five countries. Participants also answered a survey that included questions about their history of viral infections from the varicella zoster virus (VZV), which causes the chickenpox and shingles.

“To date, VZV is the only virus consistently reported to have an inverse association with glioma,” the study reads.

There was no correlation noted between glioma risk and people who had shingles, and while the association between low-grade gliomas and chickenpox was not statistically significant, the association between high-grade gliomas and chickenpox history was.

The strongest protective effect was seen in patients who developed high-grade gliomas at a younger age (under 40 years old), leading researchers to believe that the gliomas one gets at a younger age are different than those in patients who are older. This is particulary interesting, since the median age that a person is diagnosed with glioma is 55, according to the study. The age that a person got the chickenpox, on the other hand, made no difference in outcomes.

Researchers are still unclear as to why the association between the chickenpox and gliomas exists. One theory is that VZV antibodies may also have cross-reactivity to tumor cells and other oncogenic viruses. Or, it is also possible that people who are more likely to get cancer may just have weaker immune systems, which is why they got chickenpox as a child.

The study called for future research, with consideration of a few points. Before the mid-1990s, about 90 percent of children got the chickenpox. This number is now much lower, thanks to the development and approval of the VZV vaccine, which was licensed in the United States in 1995.

Authors on the study explain, “future research ascertaining whether the vaccine confers similar protection against glioma as the wild-type VZV infection is of high importance and may lead to insight into the biological mechanisms at play.”