Adult pneumococcal vaccine recommendations have been considered some of the most complicated vaccine recommendations to appropriately implement. The good news: Implementation just got simpler.
With two newly licensed pneumococcal conjugate vaccines (PCVs) on the market, the Centers for Disease Control and Prevention's (CDC's) Advisory Committee on Immunization Practices (ACIP) aimed to make timely recommendations that are based on the best available evidence. This afforded an opportunity to simplify existing pneumococcal vaccine recommendations in order to improve vaccination coverage and reduce disparities in pneumococcal disease burden among adults.
Here are five things to know.
1. Pneumococcal disease remains a burden among adults.
Pneumococcal disease, caused by Streptococcus pneumoniae or pneumococcus, can be divided into two types: invasive pneumococcal disease (IPD) and noninvasive disease. IPD is the less frequent but more severe form of illness and includes meningitis, bacteremia, and bacteremic pneumonia. CDC estimates that there were roughly 30,000 IPD cases and 3000 IPD deaths among adults aged 19 years or older in the United States in 2019. Noninvasive disease, such as nonbacteremic pneumonia, is the more frequent form of illness. Pneumococcal pneumonia is the most common clinical presentation of pneumococcal disease in adults. In 2017, it was estimated that more than 100,000 hospitalizations from pneumococcal pneumonia occurred among adults aged 19 years or older in the United States. 
2. Some adults are at a higher risk for pneumococcal disease than others.
In 2019, approximately 43% of IPD cases in adults occurred in those aged 65 years or older, whereas half were in adults aged 19-64 years who were at increased risk for pneumococcal disease. This indicates that more than 90% of current IPD burden is in these two populations.
Chronic health conditions or other factors that increase risk for pneumococcal disease include:
Cerebrospinal fluid leak
Chronic heart/liver/lung disease
Having an immunocompromising condition can also increase risk for pneumococcal disease. These conditions include:
Chronic renal failure or nephrotic syndrome
Congenital or acquired asplenia
Congenital or acquired immunodeficiency
Generalized malignancy, Hodgkin disease, leukemia, lymphoma, or multiple myeloma
Sickle cell disease or other hemoglobinopathies
Solid organ transplant
3. There are two newly licensed PCVs.
During the summer of 2021, the US Food and Drug Administration licensed two new PCVs for use in adults: PCV15 and PCV20. Prior to these newly licensed vaccines, PCV13 and pneumococcal polysaccharide vaccine (PPSV23) were recommended for use in US adults depending on age and other risk factors. Neither PCV15 nor PCV20 are currently licensed for use in children, but the manufacturers have stated that they expect to receive licensure decisions in early 2022 for PCV15 and in early-to-mid 2023 for PCV20.
There are more than 100 known serotypes of S pneumoniae. PCV15 and PCV20 target common serotypes causing IPD and pneumococcal pneumonia in the United States. PCV15 contains all PCV13 serotypes (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F) plus 22F and 33F. PCV20 contains all PCV15 serotypes plus 8, 10A, 11A, 12F, and 15B.
Immunogenicity, Vaccine Efficacy, and Vaccine Safety
Because these are new vaccines, data on vaccine effectiveness — or how well the vaccines work in real-world conditions against clinical outcomes such as IPD and pneumococcal pneumonia — are not yet available. The vaccines were approved by the FDA after phase 1 (for PCV20 only), phase 2, and phase 3 clinical trials. The trials demonstrated that each vaccine produced similar immune responses as PCV13 for shared serotypes, thus meeting noninferiority criteria.[2,3] Of note, none of these trials directly compared PCV15 with PCV20.
Clinical trial data show that PCV15 has an acceptable and comparable safety profile to PCV13 among healthy adults aged 18 years or older who have never received a pneumococcal vaccine, as well as in adults aged 65 years or older who have previously received PPSV23. Nearly 70% of adults reported having at least one side effect, with the most common being pain, redness, and swelling at the injection site; fatigue; muscle pain; joint pain; or headache. No serious vaccine-related adverse events were reported.
Clinical trial data for PCV20 showed a pattern of side effects similar to that for PCV13, both among adults aged 18 years or older who have never received a pneumococcal vaccine and adults aged 65 years or older who have previously received at least one dose of a pneumococcal vaccine. The most commonly occurring side effects were injection site pain, muscle pain, fatigue, headache, and joint pain. No serious vaccine-related adverse events were reported.
4. The same recommendation applies for all adults who are at increased risk for pneumococcal disease and have not received a pneumococcal vaccine.
In October 2021, ACIP voted in favor of using PCV15 or PCV20 for US adults. As a standard, ACIP reviews data for each new vaccine individually and compares the expected impacts against the current recommendations. Even though PCV15 and PCV20 were licensed a little over a month apart, they were both considered separately in comparison to the existing recommendations. Currently, there are no data that make direct comparisons between the two new vaccines.
On January 28, 2022, CDC published the recommendations in the Morbidity and Mortality Weekly Report (MMWR) and they became official policy.
Clinical guidance for adults who have never received a pneumococcal vaccine
CDC recommends pneumococcal conjugate vaccination for all adults who are at increased risk for pneumococcal disease, either because of their age (aged 65 years or older) or having certain medical conditions or other risk factors.
These adults should receive either PCV15 or PCV20. If PCV15 is used, this should be followed by a dose of PPSV23. The recommended interval between doses is at least 1 year. The minimum interval between doses is 8 weeks and can be considered in adults with an immunocompromising condition, cochlear implant, or cerebrospinal fluid leak.
Clinical guidance for adults who previously received PCV13 or PPSV23
Adults who are at increased risk for pneumococcal disease who have already received PPSV23 but haven't received a PCV may receive PCV15 or PCV20. The PCV15 or PCV20 dose should be administered at least 1 year after the most recent PPSV23 vaccination. If PCV15 is administered, an additional dose of PPSV23 is not indicated.
ACIP has not reviewed the incremental public health benefits of PCV15 or PCV20 use in adults who have received PCV13 with or without PPSV23. These adults should complete the previously recommended PPSV23 series, including additional doses, if indicated. However, one dose of PCV20 may be used if PPSV23 is not available. If PCV20 is used, their pneumococcal vaccinations are complete.
5. An app is available to help implement pneumococcal vaccine recommendations.
The PneumoRecs VaxAdvisor app can help vaccination providers quickly determine which pneumococcal vaccines a patient needs and when. App users simply enter a patient's age, note any specific underlying medical conditions or other risk factors, and answer a few questions about the patient's pneumococcal vaccination history. The immediate result provides patient-specific guidance that is consistent with the recent updates to CDC's adult immunization schedule.
The app is available for download on iOS and Android mobile devices, and there is also a desktop version for clinicians without a device that supports the app.
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Cite this: 5 Things to Know About Pneumococcal Disease and the New Adult Pneumococcal Vaccine Recommendations - Medscape - Feb 17, 2022.