MIKE STOBBE AP Medical Writer ATLANTA (AP) — The government declared an end to a shortage of a childhood vaccine that protects against bacterial meningitis, pneumonia and other serious infections. The shortage began in late 2007, when vaccine maker Merck & Co. announced a recall of the vaccine after identifying a sterility problem. The vaccine protects against Haemophilus (hehm-ahf-ihl-us) influenza type B, which can cause pneumonia and other infections. The Centers for Disease Control had told doctors to keep giving babies the vaccinations at two months, four months and six months. However, officials had recommended deferring a later booster dose until supplies improved. On Thursday, CDC officials said doctors can again give that booster dose, and begin to give "catch-up" doses to kids who missed it.