The impact of 10-valent and 13-valent pneumococcal conjugate vaccines on serotype 19A invasive pneumococcal disease

Abstract

The circulation in the community of pneumococcal serotype 19A, a highly invasive and frequently extremely resistant pneumococcal strain, has increased the focus on methods to control its presence and effect. Two vaccines have been developed: the 10-valent pneumococcal conjugate vaccine (PCV10) and the 13-valent pneumococcal conjugate vaccine (PCV13). Available data indicate that PCV13 is highly effective in reducing the risk of serotype 19A invasive pneumococcal disease (IPD) in both vaccinated children and unvaccinated adults. Positive data have also been published for PCV10 that suggest that the conjugated serotype 19F included in the vaccine could evoke a cross-reactive antibody response with serotype 19A. However, a great number of invasive pneumococcal disease (IPD) cases are associated with serotypes not included in either of the vaccines, and preparation of a vaccine containing all the serotypes is unrealistic. Protein vaccines are the real future to definitively reduce the pneumococcal disease burden.

Keywords:

• PCV10
• PCV13
• pneumococcal conjugate vaccine
• serotype 19A
• Streptococcus pneumoniae

Financial & competing interests disclosure

This review was supported by a grant obtained from the Italian Ministry of Health (Bando Giovani Ricercatori 2009). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• After PCV7 introduction, the proportion of IPD due to pneumococcal serotypes not included in the vaccine increased globally, with 19A being the most prevalent and increasingly resistant serotype.

• Two vaccines have recently been developed: PCV10 and PCV13.

• The available data indicate that PCV13 is highly effective in reducing the risk of development of serotype 19A IPD in both vaccinated children and unvaccinated children and adults independent of the schedule of administration used.

• Positive data have also been published for PCV10, suggesting that the conjugated serotype 19F included in the vaccine could really evoke a cross-reactive antibody response, with serotype 19A being adequate to prevent, in a number of cases, IPD due to this pneumococcal strain.

• The data available to date, together with indirect evaluations, seem to indicate that PCV13 can offer a higher likelihood of protection against serotype 19A IPD than can PCV10.

• PCV13 was found to be effective in reducing serotype 19A carriage, but the same has not been demonstrated for PCV10, suggesting a potentially lower effect of this vaccine in the reduction of IPD in both vaccinated and unvaccinated subjects.

• Further studies mainly regarding indirect vaccine effects and the impact on non-IPD infections are needed to definitively solve the problem of the superiority of PCV13 or PCV10.

• Most cases of IPD is presently associated with serotypes not included in either of the vaccines: protein vaccines are the real future to definitively reduce the pneumococcal disease burden.