The CDC’s Advisory Committee on Immunization Practices has provided us an opportunity to do a better job in providing protection from invasive pneumococcal disease for our immunocompromised adult patients. It long has been recommended that such patients receive the 23-serotype pneumococcal polysaccharide vaccine (Pneumovax 13, Merck). Note that this is a patient population that has a many-fold higher risk for invasive pneumococcal infection than other adults – even those with risk factors such as diabetes, lung or cardiac disease or advancing age. The schedule for using the vaccines is noted in the story and will be described more fully when the recommendations officially are published in the Morbidity and Mortality Weekly Report (MMWR). Goodness knows I’m all for enhanced prevention, so forgive me being already concerned whether medical providers can keep track of two pneumococcal vaccines, both in their office refrigerators and in the patients’ medical records. Although generally accepted in pediatric practice, state-based electronic immunization registries just are starting to be used in adult care. Clearly, we have a challenge ahead.
Now that this recommendation is in place, I’ve already received some questions about when the ACIP will speak to the use of pneumococcal conjugate vaccine among adults who are not immunocompromised. Not for a while yet, I’m afraid. Before the ACIP will address this important question it awaits two pieces of information. The first is an assessment of the indirect effect of the universal use of the conjugate vaccine in children. As it happens, children often transmit pneumococci to their adult contacts. Conjugate vaccine use in children reduces that transmission and consequent disease in adults caused by the serotypes in the vaccine. Early data presented at the ACIP meeting indicated exactly such a beneficial indirect effect. If that holds up, it would make the use of conjugate vaccine less cost-effective (an important consideration these days).
The second set of results awaited by the ACIP will come from the CAPITA trial ongoing in Netherlands, which is evaluating the impact of conjugate vaccine on the occurrence of community acquired pneumonia in adults aged 50 and older. If a notable protective effect is shown, it would make conjugate vaccine more cost-effective. The earliest we can expect results from the CAPITA trial is in 2013. Stay tuned.