Guidance on the use of pneumococcal vaccines in United States adults aged 19 years and older has been updated by a CDC advisory committee.

Before FDA licensing in 2021 for the 15-valent pneumococcal conjugate vaccine (PCV15) and the 20-valent PCV (PCV20), the Advisory Committee on Immunization Practices (ACIP) recommended 23-valent pneumococcal polysaccharide vaccine (PPSV23) alone (up to 2 doses), or both a single dose of 13-valent PCV (PCV13) in combination with one to three doses of PPSV23 in series (PCV13 followed by PPSV23). The use varied based on age and underlying risk for pneumococcal disease. In 2021, two new PCVs.

Now, ACIP recommendations call for the use of either PCV20 alone or PCV15 in series with PPSV23 for all adults aged 65 years and older, as well as for adults aged 19 to 64 years with certain underlying medical conditions or other risk factors, those who have not received a PCV, or those whose vaccination history is unknown.

The ACIP also specifies the use of either a single dose of PCV20 or one or more doses of PPSV23 for adults who have started their pneumococcal vaccine series with PCV13 but have not received all recommended PPSV23 doses.

“Shared clinical decision-making is recommended regarding use of a supplemental PCV20 dose for adults aged ≥65 years who have completed their recommended vaccine series with both PCV13 and PPSV23,” according to an article in the CDC’s Morbidity & Mortality Weekly Report (MMWR).

In implementation guidance, the CDC said that adults aged 19 years and older who have received PPSV23 only are recommended to receive a dose of either PCV20 or PCV15 at an interval of more than 1 year after receipt of the last PPSV23 dose. The CDC guideline was presented to the ACIP but did not go to a full vote.

Public health officials also recommended the use of PCV15 or PCV20 for adults who have received PPSV23 but have not received any PCV dose. The report included clinical guidance for adults who have received 7-valent PCV (PCV7) only and adults who are hematopoietic stem cell transplant recipients.

“Pneumococcal infections are caused by Streptococcus pneumoniae (pneumococcus), a gram-positive, facultative anaerobic bacterium, according to background information in the MMWR, which added, “In adults, pneumococcal pneumonia is the most common type of pneumococcal disease, and pneumococcus is the most common bacterial cause of pneumonia that results in hospitalization.”

The report advised that pneumococci are classified into serotypes depending on their capsular polysaccharide, which affects virulence. As of 2020, at least 100 pneumococcal serotypes were documented.

The report authors noted that, during 2018 to 2019, some 60% to 75% of all invasive pneumococcal disease in adults was caused by the 24 pneumococcal serotypes that were included in the formulations of commercially available PCV or PPSV vaccines (i.e., PCV13, PCV15, PCV20, and PPSV23).

Pneumovax23 (PPSV23) is a 23-valent vaccine that has been recommended for use since the 1980s for adults aged 65 years and older and a broader group with underlying medical conditions. In 2012, ACIP recommended PCV13 in addition to PPSV23 for use in adults aged 19 and older with an immunocompromising condition, functional or anatomic asplenia, a cerebrospinal fluid (CSF) leak, or a cochlear implant. In 2014, ACIP recommended routine use of PCV13 in series with PPSV23 for all adults aged 65 years and older based on a large, randomized, controlled trial conducted in the Netherlands that demonstrated the efficacy of PCV13 against noninvasive pneumococcal pneumonia.

In June 2019, however, ACIP voted to recommend PCV13 be no longer routinely used for all adults 65 years and older, instead advising that PCV13 should be used on the basis of shared clinical decision-making for older adults who do not have an immunocompromising condition, a CSF leak, or a cochlear implant.

“The rationale for this decision was based on additional years of data that found minimal changes in the incidence of pneumococcal disease preventable by PCV13 among adults after the PCV13 recommendation for all adults aged ≥65 years was implemented and on the historically low levels of PCV13-type disease attributed to the indirect effects of pediatric PCV13 use,” the article noted. “Although anatomic or functional asplenia, chronic renal failure, and nephrotic syndrome might not be considered immunocompromising, these conditions are included under immunocompromising conditions for pneumococcal vaccine recommendations because of the similarities in the vaccine recommendations.”

Updated CDC guidance for implementation calls for adults who—at any age—have received PCV7 to follow the recommendations for adults who have not received a pneumococcal vaccine or whose vaccination history is unknown.

Adults aged 19 years and older who are hematopoietic stem cell transplant (HSCT) recipients are recommended to receive four doses of PCV20, starting 3 to 6 months after HSCT, according to the CDC, which says that vaccinators should administer three doses of PCV20 (4 weeks apart starting 3-6 months after HSCT) and then administer a fourth PCV20 dose (6 or months after the third dose of PCV20 or 12 or more months after HSCT, whichever is later).

“If PCV20 is not available, 3 doses of PCV15 4 weeks apart, followed by a single dose of PPSV23 ≥1 year after HSCT, can be administered,” according to the guidance. “For patients with chronic graft versus host disease (GVHD) who are receiving PCV15, a fourth dose of PCV15 can be administered in place of PPSV23 because these adults are less likely to respond to PPSV23. A patient’s clinical team is best informed to determine the appropriate timing of vaccination.”

These CDC guidelines were presented to the ACIP but did not go to a full vote.

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