Hib Vaccine Shortage Extended

By Daniel J. DeNoon
WebMD Health News Reviewed by Louise Chang, MD

Nov. 20, 2008 -- The current U.S. shortage of childhood Hib vaccine will continue at least until mid-2009, the CDC warns.

The shortage began in December 2007, when Merck recalled certain lots of its Hib vaccine because of possible bacterial contamination and shut down its manufacturing facility.

This disruption of the U.S. Hib vaccine supply caused a vaccine shortage. Kids normally get Hib vaccinations at ages 2 months, 4 months, sometimes 6 months (depending on which brand of vaccine), and 12-15 months. To deal with the shortage, the CDC told doctors to continue giving the first vaccine dose, but to hold off on the booster dose (except for high-risk kids) at 12-15 months until supply resumed.

That hasn't happened. And now Merck says it won't have new vaccine until at least mid-2009.

The CDC says there's still enough Hib vaccine on hand to give kids their first shot at 2 months. And there should be enough for high-risk kids to get their booster shot, too.

Meanwhile, the CDC says there's no sign of any upsurge in Hib cases. However, the CDC warns that health departments are not doing a good enough job of analyzing samples from children with suspected Hib infection and has asked them to step up their Hib surveillance efforts.

That's important because of what happened in the U.K. in 1999. The U.K. did not include a booster shot as part of its routine Hib vaccination series for children. As a result, waning immunity led to a surge in Hib cases.

Hib stands for the bacterium Haemophilus influenzae type b. It's only one of six major types of the bacteria, but before the vaccine came along, type b caused 95% of Haemophilus infections in children less than 5 years old.

Despite its name, Haemophilus influenzae does not cause the flu. (Although it was mistakenly thought to cause flu when it was discovered, and named, during the 1890 flu epidemic).

But Hib does cause serious, potentially fatal infections. Before the vaccine became available, Hib was the main cause of bacterial meningitis -- infection of the brain and spinal cord -- of U.S. children under 5 years old. Hib can also cause pneumonia, severe swelling of the throat, and infections of the blood, joints, bones, and covering of the heart.

In the years before the Hib vaccine, some 20,000 U.S. children under 5 got severe Hib infections every year, resulting in about 1,000 deaths.

The CDC warning comes in the Nov. 21 issue of its Morbidity and Mortality Weekly Report.