Monday, October 12, 2015

Progress on Vaccine to Prevent Stomach Cancer

When it comes to news stories about infections and cancer, HPV (human papillomavirus) has dominated the headlines the past few years.  For the most part, this has been great. HPV causes nearly all cases of cervical cancer and increases the risk of multiple other cancers.  And there is an effective vaccine to protect against HPV, use of which has been slowly but steadily increasing in the United States.

Outside of HPV, though, there are many other important infections that can increase the risk of certain cancers. One of these in an infection with a bacterium called Helicobacter pylori - or H pylori for short - which is a main cause of stomach cancer.  Stomach cancer is the 15th most common cancer in the United States, but it is the 5th most common cancer globally and the 3rd leading cause of cancer death.

H pylori infections are actually quite common, generally occur early in life, and can persist lifelong.  And while the link between H pylori and cancer has been known for decades, development of an effective vaccine has been elusive.

A new study published in The Lancet last week, though, shows we may finally be making solid progress on that front.  The study, done in China with approximately 4,500 children ages 6 - 15 years old, found that a 3-dose oral vaccine could reduce early life infections with H pylori by around 70 percent in the year after vaccination.

The results, of course, weren't perfect.  Although 70 percent effectiveness is very good compared to that found in previous H pylori vaccine studies, it's still not as high as many would prefer.  And the effectiveness appeared to wane with time - dropping to around 55 percent just two years after vaccination.  Still, for an infection so common and so closely linked to an important global cancer, these results show promise that someday in the not-to-distant future there may be an effective, easy-to-administer vaccine for H pylori that could help prevent stomach cancer.

Many questions remain, however, about the potential benefits and drawbacks of such a vaccine; this recent study, though, will hopefully help move us closer to getting some of the answers.

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