Pneumococcal 15-valent and 20-valent conjugate vaccines for prevention of pneumococcal disease

Approved indication: prevention of pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, 22F, 23F and 33F in adults and children from 6 weeks of age
Vaxneuvance (Merck Sharp & Dohme)
pre-filled syringe containing 0.5 mL suspension for intramuscular injection

Approved indication: prevention of pneumococcal disease caused by Streptococcus pneumoniae serotypes 1, 3, 4, 5, 6A, 6B, 7F, 8, 9V, 10A, 11A, 12F, 14, 15B, 18C, 19A, 19F, 22F, 23F and 33F in adults aged 18 years and older
Prevenar 20 (Pfizer)
pre-filled syringe containing 0.5 mL suspension for intramuscular injection

Pneumococcal vaccines are recommended in Australia for the prevention of diseases caused by Streptococcus pneumoniae (pneumococci) in infants and children, non-Indigenous adults aged 70 years and older, Aboriginal and Torres Strait Islander adults aged 50 years and older, and people with risk conditions for pneumococcal disease.¹

The polysaccharide capsule of pneumococci has multiple capsular antigenic types (serotypes), with each serotype eliciting type-specific immunity.¹ Therefore polyvalent vaccines are needed to optimise protection against pneumococcal disease.

There are two types of pneumococcal vaccines—conjugate and polysaccharide. Pneumococcal conjugate vaccines (PCVs) are more immunogenic than pneumococcal polysaccharide vaccines (PPVs) when given to infants and people with impaired immunity. They can also induce an immune-memory response.² However, PCVs contain fewer serotypes of S. pneumoniae than the current 23-valent pneumococcal polysaccharide vaccine (Pneumovax 23, 23vPPV).

The two new conjugated vaccines (Vaxneuvance, 15-valent PCV [15vPCV] and Prevenar 20, 20-valent PCV [20vPCV]) contain 15 and 20 serotypes of S. pneumoniae respectively. This is an increase from 13 serotypes in the existing 13-valent PCV (Prevenar 13, 13vPCV). At the time of writing (October 2023), the 2 new conjugate vaccines were not funded under the National Immunisation Program, but the Australian Immunisation Handbook included interim recommendations that they may be used as alternatives to 13vPCV.¹ There is no change to the recommendations for the 23vPPV (Pneumovax 23), which continues to be recommended, in addition to a conjugate vaccine, for Aboriginal and Torres Strait Islander people and people with risk conditions for pneumococcal disease.¹

No efficacy studies have been undertaken for the 15vPCV or 20vPCV. Approval of both vaccines is based on immunogenicity data, which show noninferiority compared with the currently approved 13vPCV.^3,4

Safety data for the 15vPCV are based on double-blind, active comparator–controlled studies, in which over 4500 healthy infants (from 6 weeks of age) and toddlers (11 to 15 months of age), and over 5000 adults (aged 18 to 98 years) with stable underlying medical conditions and/or risk factors for pneumococcal disease received the vaccine. Common adverse effects were injection-site pain, headache and myalgia. These were usually mild to moderate in severity. In adults, these effects were slightly more frequent with the 15vPCV compared with the 13vPCV. Serious adverse events were comparable between the two vaccines.^5,6

Safety data for the 20vPCV are based on double-blind, active comparator–controlled studies, in which over 4000 participants aged 18 years or older received the vaccine. The most frequent adverse effects were injection-site pain, muscle pain, fatigue, headache and joint pain. The safety profile of the 20vPCV was similar to that of the 13vPCV and no new adverse reactions were identified.⁷

The dosing regimens for the 2 new vaccines are the same as the 13vPCV. Refer to the Australian Immunisation Handbook for details.¹

For infants and children, it is preferable to complete a primary course of PCV with the same formulation. However, if they started their vaccination course with 13vPCV, it is acceptable to complete the course with the 15vPCV.¹

For adults who have already received the 13vPCV, a dose of the 15vPCV is not recommended because there are no data to support repeat doses of PCV in adults, and the 13vPCV provides comparable protection against invasive pneumococcal disease.⁶ Specific advice for the 20vPCV has not yet been published.

Whether these two new conjugated vaccines are more effective at preventing pneumococcal disease than previous conjugated vaccines remains to be seen. This will need to be determined by postmarketing surveillance studies.

🅃 manufacturer provided the product information. The Transparency Score is explained in New drugs: transparency, Vol 37 No 1, Aust Prescr 2014;37:27.

At the time the comment was prepared, information about this drug was available on the websites of the Food and Drug Administration in the USA, the European Medicines Agency and the Therapeutic Goods Administration.

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