My four-month-old son just received a new vaccine at his doctor's visit. It was a strep/pneumonia/meningitis vaccine. This vaccine has only been given since February 2000. I am concerned about the side effects. I have spoken with my doctor's nurse, and she said that she did not have any information due to the short amount of time that this vaccine has been available. I am concerned that my son could contract meningitis from getting this vaccine.

Missy

Your son apparently received the new vaccine against Streptococcus pneumoniae. This organism, also known as the "pneumococcus," is the most common bacterium isolated from infants and toddlers with invasive infections. It is the most common cause of otitis media (middle-ear infection), and virtually all children will eventually develop an infection with this organism. It is also a very common cause of childhood meningitis (infection of the membranes covering the brain and spinal cord).

The only pneumococcus vaccine available before February 2000 was known as a polysaccharide vaccine. The polysaccharide is part of the cell wall of the pneumococcus. Unfortunately, there are about 80 different strains of pneumococcus, each with a different polysaccharide. Therefore, for the vaccine to be effective, it would have to have many, if not all, of these different polysaccharides, which it did not. In addition, polysaccharide vaccines are not very effective in inducing long-term immunity. In children under two years old, these vaccines do not work at all.

The new vaccine attaches ("conjugates") the seven most common pneumococcal polysaccharides to a protein that helps produce immunity. This so-called conjugate vaccine is similar to the highly effective vaccine used for Haemophilus influenzae. Since the new vaccine uses polysaccharide from only seven strains, it will not prevent all cases of invasive pneumococcal disease. In February 2000, the U.S. Food and Drug Administration (FDA) approved the vaccine for use in infants and toddlers. As of this writing, there is no official recommendation concerning use in all children. According to the FDA, this vaccine is very safe and effective. In a very large study involving thousands of children, the vaccine prevented 100 percent of cases of invasive pneumococcal disease involving the strains represented in the vaccine. Overall, it prevented 90 percent of the cases of disease due to any strain.

Since the vaccine does not contain live organisms, one cannot develop meningitis or any other pneumococcal infection from the virus. As with any vaccine, there can be side effects. In the various studies, the most common side effects were reactions at the injection site, irritability, drowsiness and decreased appetite. Low-grade fever was seen in about 20 percent of vaccine recipients.