You'll recall KARK told you last week that Merck announced a voluntary recall of the vaccine.
The HIB vaccine is normally given in two doses -- initially at 2 months and a booster shot at 12 to 15 months, to protect against meningitis and pneumonia.
CDC officials are now recommending doctors hold off on the booster shot until the vaccine supply improves.
Experts say this should not lead to an increase in meningitis or pneumonia.
The vaccine was recalled because the manufacturing plant failed certain quality-control checks.
There's no evidence the vaccine itself was contaminated.