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The burden of pneumococcal disease and challenges with adult vaccination
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Streptococcus pneumoniae has long been recognized as a leading cause of serious illnesses, such as pneumonia, bacteremia and meningitis in children as well as adults. The 2013 Active Bacterial Core Surveillance (ABCs) Report for S. pneumoniae estimates that there were 33,500 cases and 3,500 deaths due to invasive pneumococcal disease in the United States that year. The estimation of the burden of invasive pneumococcal disease is straightforward since by definition it is the isolation of S. pneumoniae from a normally sterile site. The highest incidence of invasive pneumococcal disease is in adults aged 65 years and older, in children aged younger than 2 years, and in individuals with certain underlying conditions, including those with immunosuppression. One-third of reported invasive pneumococcal disease occurs in those aged 65 years and older, and since approximately 15% of the U.S. population is in this age group, the burden of disease is high in the elderly.
As opposed to invasive disease, the incidence of pneumococcal pneumonia is not as easy to determine since the causative pathogen is not identified in the majority of pneumonia cases. However, a recently published study analyzed the trends of microbiologic pathogens in hospitalized adult patients. This study found the incidence of pneumonia caused by S. pneumoniae has decreased from 5.7% in 1993 to 1.7% in 2011.
The Advisory Committee on Immunization Practices (ACIP) updated its pneumococcal vaccination guidelines in September among older adults, whereas the recommendations in infants and children remain unchanged. The guidelines now recommend that adults aged 65 years and older receive both Prevnar 13 (PCV13; Pfizer) and Pneumovax 23 (PPSV23; Merck) in series. In addition, both vaccines also are recommended for patients aged younger than 65 years with certain chronic conditions, such as those who are immunocompromised (HIV, cancer, solid organ transplants, etc.), those with functional or anatomic asplenia, cerebral spinal fluid leak or cochlear implants. Some experts have predicted that the use of PCV13 in adults will one day become irrelevant as the prevalence of the serotypes in PCV13 diminishes due to the excellent uptake of this vaccine in the pediatric population. This is based upon published data documenting the reduced pneumococcal disease burden after the introduction of Prevnar 7 (PCV7; Pfizer) in U.S. children. The incidence of pneumococcal disease in adults caused by the serotypes contained in PCV7 has been reduced by more than 90% since PCV7 was introduced in 2000. The use of these vaccines in children has reduced pneumococcal infections directly in children and indirectly among adults due to the herd effect. It is anticipated that the same effects will be seen after the widespread use of PCV13 in children, which was introduced in 2010. This foreseen herd immunity effect is one of the arguments against the new recommendations to immunize adults with PCV13.
Jeff Brock
Pneumococcal immunization rates
Pneumococcal immunization rates among those who fall into the high-risk groups remain low, particularly those aged 18 to 64 years, with only 20% of those patients having been vaccinated, according to data from the CDC. Rates of vaccination are approximately 60% in those aged older than 65 years, which is substantially higher than the high-risk younger patients, but this rate has been unchanged for several years. The Healthy People 2020 goal for pneumococcal vaccination among those aged 65 years and older is 90%. As you can see, we still have a long way to go to achieve this level of immunization compliance.
Vaccination challenges
Hospitals that have a nursing-driven pneumococcal vaccination protocol are finding it difficult to implement the new ACIP pneumococcal guidelines because of several factors. First, many patients simply do not recall if they have been vaccinated. Others remember that they received a “pneumonia shot,” but are unclear of when they were vaccinated and do not know if it was PCV13 or PPSV23. Also, access to state vaccination registries has been limited in the hospital setting, making it difficult to look up the patient’s vaccination history. Where I practice in Iowa, adult immunization entry into the vaccination registry has been limited, so using the registry to obtain patient vaccination history may not be useful. Ultimately, additional phone calls would need to be made in order to attempt to track down the needed information to decide which vaccine the patient needs. Unfortunately, this takes a significant amount of time away from direct patient care duties. However, health care systems with a fully integrated medical record that have access to this information may not have as much of an issue obtaining their patients’ outpatient vaccination history. Because of the more complicated vaccination schedule now recommended, some hospitals have elected to discontinue their pneumococcal vaccination protocols since they no longer need to be reported to the Joint Commission nor to CMS for the inpatient quality reporting program. In reality, the best place for patients to obtain their pneumococcal vaccinations may be in their physician’s office or their local community pharmacy, both of which will be able to more efficiently track their patients’ immunization history.
The ultimate goal should be to vaccinate all of those who are candidates according to the new ACIP guidelines to help prevent serious illness associated with this organism because it has a tremendous impact on the lives of our patients, as well as our health care system. However, there are some challenges with providing a pneumococcal vaccine series to adult patients, particularly in the hospital setting. With hospitals now deciding to discontinue pneumococcal vaccination screening, it will be interesting to follow vaccination rates in the coming years. Hopefully we do not see a decline in immunization rates among adults. In order to increase pneumococcal vaccination rates to achieve the Healthy People 2020 goal, we need to identify efficient approaches to ensure that our patients receive the appropriate vaccinations.
References:
CDC. Pneumococcal vaccination among adults aged 18 and over, by selected characteristics: United States, selected years 1989-2012. Accessed Jan. 30, 2015, from www.cdc.gov/nchs/data/hus/2012/081.pdf.
Musher DM. Infect Dis Clin North Am. 2013;27:229-241.
Smith SB, et al. JAMA Intern Med. 2014;174:1837-1839.
Tomczyk S, et al. MMWR. 2014;63:822-825.
For more information:
Jeff Brock, PharmD, MBA, is an infectious disease pharmacy specialist at Mercy Medical Center in Des Moines, Iowa. He can be reached at: JBrock@mercydesmoines.org.
Disclosure: Brock reports no relevant financial disclosures.