Pneumococcus is a common bacterium that can cause relatively minor illnesses such as middle ear infection and sinusitis as well as more serious illnesses such as pneumonia and meningitis . In March 2000, a vaccine that protects against seven varieties of pneumococcus bacteria (PCV-7) was made available for infants and young children. Vaccinated children are less likely to spread the bacteria to other children and adults.

But has the PCV-7 vaccine actually decreased the occurrence of pneumococcal infections in adults? In an article published in the October 26, 2005 Journal of the American Medical Association , researchers report that cases of pneumococcal disease have decreased significantly among adults aged 50 years and older in the years since children started routinely receiving the PCV-7 vaccine.

About the Study

The researchers analyzed data collected by the US Centers for Disease Control and Prevention (CDC) Emerging Infections Program on 4,978,000 adults, aged 50 years and older living in eight states. They noted all cases of invasive pneumococcal disease (meningitis, pneumonia, and bacteremia) that the CDC’s program diagnosed in these men and women from 1998 to 2003.

The incidence of invasive pneumococcal disease caused by the seven varieties of pneumococcus bacteria covered by the PCV-7 vaccine declined 55% from 22.4 cases per 100,000 adults in 1998-1999 (before the vaccine was introduced) to 10.2 cases per 100,000 adults in 2002-2003 (after the vaccine was introduced). This was a significant decline.

One limitation of this study was that the percentage of children immunized with the PCV-7 vaccine varied considerably.

How Does This Affect You?

This study found that the incidence of invasive pneumococcal disease declined significantly in older adults in the years after the PCV-7 vaccine was introduced to children in the community.

Usually when a child brings an illness home from daycare or school, it’s nothing more than a bothersome cold. But the possibility always exists that they’ll bring home something more serious. The PCV-7 vaccine protects children from pneumococcal infection, but it also reduces the likelihood that an immunized child will transmit a pneumococcal infection to another child or adult in the community.

As with any truly successful vaccine program, even unvaccinated members of a community stand to benefit, a concept parents ought to bear in mind when immunizing their own children. PCV-7 and other universal vaccine programs are not just good for children, but for the entire community.