Authorities in the U.S. say hold back on children's Hib vaccine

Health authorities in U.S. are advising doctors to defer giving booster shots of a childhood vaccine following suspicions that production equipment may not have been properly sterilized.

According to the U.S. Centers for Disease Control and Prevention (CDC), 11 batches of the vaccine against Hib disease (Haemophilus influenzae type b) PedvaxHIB, and 2 batches of Comvax have been recalled by the drug company Merck - this equates to 1.2 million doses.

The vaccines were recalled because of product sterility issues.

Both recalled vaccines protect against Hib and prevent serious bacterial infections, including meningitis and pneumonia and Comvax also prevents hepatitis B.

Hib was once the major cause of bacterial meningitis in children less than 5 years old.

The recommendation by the CDC, has the support of the Advisory Committee on Immunization Practices, the American Academy of Pediatrics and the American Academy of Family Physicians.

Routine Hib vaccine booster doses are typically given at age 12 and 15 months; the recall is a precaution and no tainted vaccines have been found.

The CDC says children at high risk for Hib disease should continue to receive the booster dose, they include American Indian children, Alaska Native children and children with asplenia, sickle cell disease, HIV and other immunodeficiency conditions and certain cancers.

The CDC is advising doctors to keep a record of which patients delay the vaccination and to contact them once the vaccine supply improves.

Merck says the vaccines were made in West Point, Pennsylvania, and distributed from April 2007; all but one lot was distributed in the United States.

According to the CDC drug company Sanofi Aventis also makes Hib vaccines which are not part of the recall but they are unlikely to be able provide enough Hib vaccines to replace the shortage.

The CDC recommends the Hib vaccine for all children under 5 years old in the U.S., with doses starting when children are 2 months old it is not related to the flu vaccine.