CDC’s pneumococcal vaccine recommendations for adults aim to address the transmission and management of pneumococcal disease. Streptococcus pneumoniae, the bacterial culprit, primarily spreads through respiratory droplets, impacting vulnerable populations, especially those with underlying health conditions. The introduction of new vaccines, PCV15 and PCV20, has expanded prevention options. The report advises tailored vaccination strategies for adults based on age, previous vaccines, and health status, emphasizing the importance of ongoing vigilance in the face of evolving pneumococcal disease patterns.
Guidelines for Pneumococcal Vaccination in Adults by the CDC
Pneumococcal Disease Overview
Pneumococcal disease, caused by the bacterium Streptococcus pneumoniae (pneumococcus), is an infection that can range from mild to severe. Pneumococcus primarily resides in the upper respiratory tract and spreads through respiratory droplets. While young children are common carriers, older adults in certain circumstances, such as those in nursing homes, close contact with young children, or smokers, face elevated risks. Adults with underlying health conditions like heart, lung, liver, kidney diseases, or diabetes are also at greater risk.
In 2017, a U.S. surveillance study found varying incidence rates of pneumococcal pneumonia, with 12 cases per 100,000 in adults aged 18 to 49 and 105 cases per 100,000 in those aged 65 and older. During the early stages of the COVID-19 pandemic, there was a decrease in pneumococcal disease, possibly due to nonpharmaceutical interventions. However, recent data suggests an increase in invasive pneumococcal disease after the relaxation of these interventions.
Management of Pneumococcal Disease
Pneumococcal disease outbreaks have occurred in diverse settings, including military facilities, hospitals, long-term care centers, and correctional facilities. While the CDC does not provide specific recommendations for individuals exposed to patients with pneumococcal disease, measures such as vaccination, antimicrobial prophylaxis, patient isolation, respiratory hygiene, and movement restriction are used to control outbreaks.
A systematic review highlighted the effectiveness of antibiotics like azithromycin, amoxicillin, penicillin G, and levofloxacin in managing pneumococcal disease outbreaks. Vaccination offers more prolonged protection compared to antimicrobial chemoprophylaxis.
Pneumococcal Vaccines for Adults
Before 2021, the Advisory Committee on Immunization Practices (ACIP) recommended the 23-valent pneumococcal polysaccharide vaccine (PPSV23) alone or combined with the 13-valent pneumococcal conjugate vaccine (PCV13) for U.S. adults, depending on age. In 2021, the U.S. FDA approved two new pneumococcal conjugate vaccines (PCV15 and PCV20) for adults aged 18 and older. Currently, the U.S. has one PPSV and three PCVs licensed for use.
Both PPSV and PCV induce immune responses differently, with PCVs generally being more effective due to higher serotype-specific immunoglobulin G (IgG) levels.
Despite the decline in PCV-type pneumococcal disease in children, the incidence of invasive pneumococcal disease (IPD) did not decrease between 2014 and 2019. Vaccination coverage with PCV13 increased significantly in adults aged 65 and older since 2014.
PCV15 and PCV20 are administered intramuscularly at 0.5 mL doses. If these are unavailable, PCV13 can be used.
PPSV23 can be given intramuscularly or subcutaneously, with no significant difference in immunogenicity based on the administration route. These vaccines are available in single-dose prefilled syringes.
ACIP’s current recommendations provide specific guidance on pneumococcal vaccination for adults:
1. For adults aged 65 and older, PCV20 or PCV15 can be used alone or in series with PPSV23. These vaccines are also suitable for adults aged 19-64 with underlying medical conditions, with varied dosages.
2. Adults who begin their pneumococcal vaccination series with PCV13 but do not complete all doses are recommended to receive either a single dose of PCV20 or multiple doses of PPSV23.
3. Clinicians should assess if adults over 65 who completed the recommended vaccine series require additional PCV20 doses. The report also includes clinical guidance for adults who received the 7-valent PCV (PCV7) only and for hematopoietic stem cell transplant recipients.