Prevnar 20 (PCV20)

What Pneumococcal 20-valent Conjugate Vaccine is and how it works

Prevnar 20 / Prevenar 20 is a vaccine that helps protect against invasive disease, pneumonia, and (in young children) middle-ear infections caused by 20 different types (serotypes) of the bacterium Streptococcus pneumoniae. It works by training the immune system to recognise and fight these specific pneumococcal serotypes before a real infection takes hold. (1) (2)

This vaccine is given as an injection by a doctor, nurse, or pharmacist, following an age-based schedule -- it is not something you take or dose yourself. It has no boxed warning, but like all vaccines it carries a small risk of allergic reaction, so it is given where medical treatment for a severe reaction is immediately available.

Mechanism of action: how Pneumococcal 20-valent Conjugate Vaccine works

Prevnar 20/Prevenar 20 is a 20-valent pneumococcal conjugate vaccine: purified capsular polysaccharides from 20 S. pneumoniae serotypes are each individually conjugated to CRM197, a non-toxic carrier protein derived from diphtheria toxin, to elicit a T-cell-dependent immune response with stronger and longer-lasting antibody production (including in infants) than an unconjugated polysaccharide vaccine. (1)

What Pneumococcal 20-valent Conjugate Vaccine is used for

Before taking Pneumococcal 20-valent Conjugate Vaccine

Do not take / not appropriate for

• This vaccine should not be given to anyone who has had a severe allergic reaction (such as anaphylaxis) to a previous dose of Prevnar 20/Prevenar 20, to any of its components, or to diphtheria toxoid (the carrier protein used in this and some other vaccines). (all countries) (1) (2)
• Vaccination is generally deferred (postponed, not cancelled) during an acute severe febrile illness -- your immunisation provider will decide when it is safe to proceed. (all countries) (2)

Tell your clinician about

• Any past severe allergic reaction to this vaccine, an earlier pneumococcal vaccine, or to diphtheria-toxoid-containing vaccines.
• Whether your baby was born prematurely -- the timing of vaccination and a period of monitoring afterwards may need individual consideration.
• Any bleeding disorder, or if you take a blood thinner, since an intramuscular injection needs extra care in these situations.
• Any condition or treatment that weakens the immune system, which may mean the vaccine works less well and needs individualised advice.
• Whether you are pregnant, plan to become pregnant, or are breastfeeding.

How to take Pneumococcal 20-valent Conjugate Vaccine

• This is a vaccine given as an injection into a muscle (the thigh in infants, the upper arm in older children and adults) by a doctor, nurse, or pharmacist -- it is never self-administered.
• The number of doses and the timing between them depend on the age at which the immunisation series is started and any prior pneumococcal vaccination -- your immunisation provider follows the age-based schedule below.
• Appropriate medical treatment must be available at the point of vaccination in case of a rare severe allergic reaction.

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6)

Missed dose

If a scheduled dose in the immunisation series is missed or delayed, contact your immunisation provider to arrange the next dose as soon as practical -- there is no need to restart the whole series, but your provider will confirm the right next step for your age and history.

Overdose

An overdose is not applicable in the usual sense for a single-dose pre-filled syringe given by a healthcare professional. If you have concerns about vaccine administration or develop concerning symptoms afterwards, contact your immunisation provider or seek medical attention. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Serious warnings

Interactions

• This vaccine can generally be given at the same visit as other routinely recommended vaccines, using separate injection sites and syringes, per official immunisation schedules -- your immunisation provider will confirm what is appropriate for your age and history. (1)
• In people with a weakened immune system (for example, from a medical condition or immunosuppressive treatment), the immune response to the vaccine may be reduced -- this does not necessarily mean it should not be given, but timing and expectations should be discussed with your clinician. (2)

Pregnancy, breastfeeding, kidney/liver function, age

Monitoring

Before starting

• Review of allergy history to this vaccine, diphtheria-toxoid-containing vaccines, or any component
• Confirmation of prior pneumococcal vaccination history to determine the correct dose/schedule
• For infants born prematurely, review of respiratory status before deciding on timing

During treatment

• Brief observation period after the injection is standard practice for any vaccine, to watch for an immediate allergic reaction.
• For some very premature infants, a period of respiratory monitoring after vaccination may be considered.

Storage

Stored and handled by healthcare providers in a refrigerator at 2C to 8C, protected from light, and not frozen -- this is a clinic-administered product, not one that patients store at home.

Frequently asked questions

References

1. PREVNAR 20 (Pneumococcal 20-valent Conjugate Vaccine) suspension for intramuscular injection -- full prescribing informationU.S. Food and Drug Administration / DailyMed (NIH), full prescribing information, Pfizer Inc. · United States · accessed 2026-07-30 · source 1
2. Prevenar 20 suspension for injection in pre-filled syringe -- Summary of Product Characteristicselectronic medicines compendium (emc), United Kingdom -- Pfizer Limited · United Kingdom · accessed 2026-07-30 · source 2
3. Prevenar 20 (previously Apexxnar) -- EPAR medicine overviewEuropean Medicines Agency (EMA), EPAR · European Union · accessed 2026-07-30 · source 3
4. PREVNAR 20 (Pneumococcal 20-valent Conjugate Vaccine [Diphtheria CRM197 Protein]) -- Product MonographHealth Canada, Drug Product Database / Summary Basis of Decision, Pfizer Canada · Canada · accessed 2026-07-30 · source 4
5. Prevenar 20 pneumococcal polysaccharide conjugate vaccine -- ARTG entry 376353 / AusPARTherapeutic Goods Administration (TGA), Australia · Australia · accessed 2026-07-30 · source 5
6. Medsafe site search for 'prevenar'/'Prevnar 20' data sheetsMedsafe (New Zealand regulator) -- direct site search · New Zealand · accessed 2026-07-30 · source 6

Brand names by country

Single-ingredient Pneumococcal 20-valent Conjugate Vaccine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries