The vaccine, which goes under the brand name Prevnar, would be given in four doses to children ages two, four, six and 12 months old. It protects against some strains of pneumonia, bacterial meningitis and pneumococcal bacteremia, which infects the bloodstream.
Critics say the vaccine costs too much and they are worried about potential side effects.
Supporters say the Colorado State Board of Health's decision to add the pneumococcal vaccine could save children's lives. Colorado would be the first state to require the immunization for preschool children younger than two, said Rebecca Jordan, manager for the immunization program at the state Department of Public Health and Environment. Only children under 2 would have to get the pneumococcal vaccine because older children have stronger immune systems, officials said. Health plans usually cover the cost, but state officials worry there won't be enough federal money to cover those on Medicaid or the uninsured. Potential side effects include swelling and low-grade viral infections.