Pneumococcal vaccine: underuse cannot be justified.

The pneumococcal vaccines are underutilized in the elderly population, with only 35% of them receiving the vaccine (and even fewer in younger populations with underlying conditions making them susceptible to pneumonia). Why are these percentages so low? It is a matter of opinion, but I think three important factors are involved.

First, I don't believe that pneumococcal vaccine is as effectively promoted to the public as some other vaccines. Second, although internists are aware of the vaccine, they are generally less motivated to provide the preventive care represented by vaccination.

A third factor has been conflicting reports about the effectiveness of the vaccine. Studies clearly show that vaccine is effective in preventing invasive pneumococcal disease, i.e., the most serious kinds of pneumococcal infections, such as meningitis and bacteremia. The studies are less conclusive, though, in demonstrating efficacy against pneumococcal pneumonia, and this has tempered clinicians' enthusiasm for the vaccine.

Perhaps this might be addressed by remembering what vaccination is to be used for. Vaccination prevents the most serious outcomes, such as death and prolonged hospitalizations, and those occur most often as a result of bacteremia. The vaccine is clearly efficacious against bacteremia. This is especially important in the geriatric population, because pneumococcal bacteremia is relatively frequent in those over 65, an age when the incidence goes dramatically up. Mortality in the elderly from this disease is very high, around 40%.

Thus, ethically and economically, it is clearly efficacious to use the vaccine, if only to prevent bacteremia. Given the minor expense of the vaccine and the fact that it is perfectly safe, the fact that it may not be all that efficacious against pneumonia doesn't bother me, as long as I know that it is efficacious against bacteremia.

I am reinforced in my commitment to vaccination by the knowledge that the emergence of drug resistance has made pneumococcal strains more difficult to treat. Under these circumstances, preventing some cases of pneumococcal pneumonia is better than preventing none at all.

Robert Breiman, MD, is director of the National Vaccine Program at the Centers for Disease Control and Prevention, Atlanta, GA. For further Information, [phone].