The pneumonia vaccine is a shot that protects against infections caused by Streptococcus pneumoniae, a type of bacteria responsible for most cases of bacterial pneumonia as well as ear infections, sinus infections, meningitis, and bloodstream infections. There are currently four pneumonia vaccines available in the United States, each covering a different number of bacterial strains. The CDC recommends them routinely for children under 5 and adults 50 and older, with earlier vaccination for people with certain health conditions.
How the Vaccine Works
Pneumococcal bacteria have an outer shell made of sugar molecules called a capsule. Each strain of the bacteria has a slightly different capsule, and your immune system needs to learn to recognize each one individually. The vaccines contain pieces of these capsules, training your immune system to build defenses against specific strains before you ever encounter the real bacteria.
There are two types of pneumonia vaccines, and they work differently. Conjugate vaccines (the PCV type) attach those capsule pieces to a protein carrier, which triggers a stronger, longer-lasting immune response involving both the antibody-producing and memory-building parts of your immune system. The polysaccharide vaccine (PPSV23) uses the capsule pieces alone. It still generates a protective response, but the immunity it creates tends to fade faster and doesn’t build the same depth of immune memory.
Available Vaccines and What They Cover
The number at the end of each vaccine’s name tells you how many bacterial strains it covers:
- PCV15 (Vaxneuvance): Conjugate vaccine covering 15 strains
- PCV20 (Prevnar 20): Conjugate vaccine covering 20 strains
- PCV21 (Capvaxive): Conjugate vaccine covering 21 strains
- PPSV23 (Pneumovax 23): Polysaccharide vaccine covering 23 strains
PCV15, PCV20, and PCV21 are newer vaccines approved based on clinical trial data showing they produce immune responses comparable to earlier conjugate vaccines. Real-world effectiveness data for these specific versions is still being collected. The older polysaccharide vaccine, PPSV23, has been studied extensively and protects about 6 to 7 out of 10 healthy adults against invasive pneumococcal disease caused by the strains it covers.
How Effective Is It?
Effectiveness depends on the type of vaccine, the person’s overall health, and the type of infection. Against the most dangerous form of pneumococcal disease, where bacteria invade the bloodstream or brain, randomized trials found pooled vaccine effectiveness of about 73%. Observational studies in real-world settings put the number closer to 45% in healthy older adults. For pneumonia specifically, clinical trials showed effectiveness around 64%, while observational studies found roughly 48% protection.
The earlier conjugate vaccine PCV13, a predecessor to the newer versions, showed 74% effectiveness against pneumonia caused by the specific strains it targeted. Health status matters significantly. In a large English study of adults 65 and older, the polysaccharide vaccine was 45% effective in people with no underlying risk factors but only 25% effective in those with chronic health conditions and 13% effective in people with weakened immune systems. Even partial protection, though, can mean the difference between a mild illness and hospitalization.
Who Should Get Vaccinated
The CDC recommends pneumococcal vaccination for two main groups as a matter of routine: all children under 5 and all adults 50 and older. Beyond those groups, people of any age with certain health conditions should also be vaccinated.
Conditions that qualify younger adults (under 50) for vaccination include:
- Lung conditions: COPD, emphysema, asthma
- Heart conditions: Congestive heart failure, cardiomyopathy (not high blood pressure alone)
- Other chronic conditions: Diabetes, chronic liver disease, chronic kidney disease
- Immune-related factors: Any immunocompromising condition
- Lifestyle and other factors: Cigarette smoking, alcoholism, cochlear implants, cerebrospinal fluid leaks
The Vaccination Schedule
Children
Infants receive a four-dose series of a conjugate vaccine (PCV15 or PCV20), with one shot at each of these ages: 2 months, 4 months, 6 months, and 12 to 15 months. Children between 2 and 18 with certain medical conditions may need additional doses.
Adults 50 and Older
If you’ve never received a pneumococcal conjugate vaccine, you need one dose of PCV15, PCV20, or PCV21. Your choice of vaccine determines whether you need a follow-up shot. If you get PCV20 or PCV21, you’re done with one visit. If you get PCV15, you’ll need a dose of PPSV23 about a year later to broaden your coverage. People with weakened immune systems, cochlear implants, or cerebrospinal fluid leaks can shorten that gap to eight weeks.
Adults 65 and older who previously received both PCV13 and PPSV23 can discuss with their provider whether an additional dose of PCV20 or PCV21 would be worthwhile, since these newer vaccines cover strains not included in the older combination.
Side Effects
Side effects are mild and typically last one to two days. The most common reactions include soreness, redness, or swelling at the injection site, along with fatigue, headache, muscle pain, decreased appetite, and low-grade fever. Some people experience chills or limited movement in the arm that received the shot. Children may be drowsier than usual or develop a mild rash. These reactions are similar across all the available pneumococcal vaccines.
Cost and Insurance Coverage
Medicare Part B covers pneumococcal vaccines and their administration as a preventive benefit. Most private insurance plans also cover recommended vaccines at no out-of-pocket cost under the Affordable Care Act’s preventive care provisions. For children, the Vaccines for Children program provides free pneumococcal vaccines to those who are uninsured, underinsured, or enrolled in Medicaid.