Capvaxive

Capvaxive (pneumococcal 21-valent conjugate vaccine) is used to prevent invasive pneumococcal disease and pneumococcal pneumonia in adults aged 18 years and older. It is also approved for children and adolescents aged 2 to 17 years who are at increased risk for pneumococcal disease due to certain medical conditions. Capvaxive is a single-dose vaccine.

Capvaxive targets Streptococcus pneumoniae (S. pneumoniae), bacteria responsible for serious infections, including:

• Pneumonia (lung infection)
• Meningitis (infection of the membranes surrounding the brain and spinal cord)
• Bacteremia (bloodstream infection).

The vaccine works by stimulating the immune system to produce antibodies against specific pneumococcal serotypes through a process called opsonophagocytosis. Antibodies bind to the bacteria, tagging them for destruction by immune cells called phagocytes.

Capvaxive contains 21 polysaccharide antigens but protects against 22 S. pneumoniae serotypes. This is because the 15B antigen is chemically modified before conjugation, producing antibodies that cross-react with and also protect against serotype 15C. Capvaxive covers 8 unique serotypes not included in any other currently licensed pneumococcal vaccine.

Capvaxive received FDA approval on June 17, 2024. The pneumonia prevention indication was granted under accelerated approval based on immune response data. Continued approval for this indication may depend on the results of a confirmatory clinical trial.

Capvaxive is manufactured by Merck Sharp & Dohme LLC. You cannot get pneumococcal disease from Capvaxive. Like all vaccines, Capvaxive may not protect everyone who receives it.

Allergic reactions

Healthcare providers should have treatment immediately available to manage potential anaphylactic reactions following administration of Capvaxive. Do not receive Capvaxive if you have had a severe allergic reaction (such as anaphylaxis) to any component of the vaccine or to diphtheria toxoid.

Fainting (syncope)

Fainting can occur following any injectable vaccine, including Capvaxive. If you feel dizzy or lightheaded after receiving this vaccine, tell your provider immediately. Vaccination providers should have procedures in place to avoid injury from fainting. You will typically be asked to remain seated for 15 minutes after vaccination so that any reaction can be monitored.

Weakened immune system

If you have a weakened immune system or are taking immunosuppressive therapy (such as corticosteroids or biologic medicines), you may have a reduced immune response to Capvaxive and may not be fully protected. Talk to your doctor about whether this vaccine is still appropriate for you.

Do not receive Capvaxive if you have ever had a severe allergic reaction to a pneumococcal or diphtheria toxoid vaccine, or to any of the inactive ingredients in Capvaxive.

Tell the vaccination provider if you:

• Have had an allergic reaction to any vaccine
• Have a weakened immune system or a condition that affects your immune response
• Are taking medications that may suppress the immune system, such as corticosteroids, immunosuppressants, or biologics
• Are pregnant or plan to become pregnant
• Are breastfeeding or plan to breastfeed.

You can still receive Capvaxive if you have a minor cold. If you have a more severe illness with a fever or active infection, wait until you have recovered before receiving this vaccine.

Common side effects

The most common side effects of Capvaxive in adults aged 18 to 49 are:

• Injection-site pain
• Fatigue
• Headache
• Muscle aches (myalgia)
• Injection-site redness
• Injection-site swelling.

The most common side effects of Capvaxive in adults aged 50 and older are:

• Injection-site pain
• Fatigue
• Headache.

The most common side effects of Capvaxive in children aged 2 to 17 (high-risk only) are:

• Injection-site pain
• Injection-site redness
• Fatigue
• Injection-site swelling
• Headache
• Malaise (general feeling of being unwell)
• Irritability.

Serious side effects

Serious side effects are uncommon. Seek emergency medical care immediately if you notice signs of a severe allergic reaction after receiving Capvaxive, including:

• Wheezing or difficulty breathing
• Swelling of the face, lips, or tongue
• Hives or rash.

Other serious reactions reported in clinical trials included injection-site cellulitis requiring hospitalization and fainting (syncope) within minutes of vaccination. See the warnings section below for more information on fainting.

Tell your vaccination provider about all side effects you experience. Keep a record of any reactions, as this information is important if you ever need another pneumococcal vaccine in the future.

Report side effects to Merck Sharp & Dohme LLC at 1-877-888-4231, or to the Vaccine Adverse Event Reporting System (VAERS) at 1-800-822-7967, or online at www.vaers.hhs.gov.

Capvaxive is given as a single injection into the muscle, usually in the upper arm. No booster dose is required.

Usual dose (all ages) for pneumococcal disease prevention

• 0.5 mL given intramuscularly as a single dose.

Because Capvaxive is given as a single dose, there is no missed dose concern. An overdose of this vaccine is unlikely to occur.

Tell your vaccination provider if you have recently received any drugs or treatments that can weaken the immune system, including:

• Corticosteroids (steroid medicines)
• Biologic medicines for psoriasis, rheumatoid arthritis, or other autoimmune conditions
• Medicines to prevent rejection after an organ transplant

This list is not complete. Other drugs may interact with Capvaxive, including prescription and over-the-counter medicines, vitamins, and herbal products.

Active ingredients: Purified capsular polysaccharides from 21 types of S. pneumoniae, each individually conjugated to CRM197 carrier protein (a nontoxic form of diphtheria toxin). These components are not alive and cannot cause disease.

Inactive ingredients: L-histidine, polysorbate 20, sodium chloride, water for injection.

Capvaxive does not contain any preservatives.