Pneumococcal vaccine

A pneumococcal vaccine is a vaccine against Streptococcus pneumoniae.

Types include:
 * Pneumococcal polysaccharide vaccine
 * Pneumococcal conjugate vaccine

Vaccination in the USA
In the USA, a heptavalent pneumococcal conjugate vaccine vaccine (PCV 7) (e.g. Prevenar ) is recommended since 2000 for all children aged 2–23 months and for at-risk children aged 24–59 months. The normally 4-doses series is given at 2, 4, 6 & 12–14 months of age. Protection is good against deep pneumococcal infections (especially septicemia and meningitis). Similar 9-, 10-, and 13-valent vaccines have been tested. However, if a child is exposed to a serotype of pneumococcus that is not contained in the vaccine, he/she is not afforded any protection. This limitation, and the ability of capsular-polysaccharide conjugate vaccines to promote the spread of non-covered serotypes, has led to research into vaccines that would provide species-wide protection.

Pneumococcal polysaccharide vaccine (Pneumovax is one brand) gives at least 85% protection in those under 55 years of age for five years or longer. Immunization is suggested for those at highest risk of infection, including those 65 years or older; generally the vaccine should be a single lifetime dose, as there is a high risk of side effects if repeated. The standard 23-valent vaccines are ineffective for children under two years old.

The current guidelines of the American College of Physicians call for administration of the immunization between ages 2 and 65 when indicated, or at age 65. If someone received the immunization before age 60, the guidelines call for a one-time revaccination.

Revaccination at periodic intervals is also indicated for those with other conditions such as asplenia or nephrotic syndrome.

Vaccination in the UK
It was announced in February 2006 that the UK government would introduce vaccination with the conjugate vaccine in children aged 2, 4 and 13 months. This is expected to start on September 4,2006 and is to include changes to the immunisation programme in general. In 2009, the European Medicines Agency approved the use of a 10-valent pneumcoccal conjugate vaccine for use in Europe.

Vaccination worldwide
Pneumococcal vaccines Accelerated Development and Introduction Plan (PnemoADIP) is a program to accelerate the evaluation and access to new pneumococcal vaccines in the developing world. PneumoADIP is funded by the Global Alliance for Vaccines and Immunization (GAVI). Thirty GAVI countries have expressed interest in participating by 2010. PneumoADIP aims to save 5.4 million children by 2030.

Vaccine research
Due to the geographic distribution of pneumococcal serotypes, additional research is needed to find the most efficacious vaccine for developing-world populations. In a previous study, the most common pneumococcal serotypes or groups from developed countries were found to be, in descending order, 14, 6, 19, 18, 9, 23, 7, 4, 1 and 15. In developing countries the order was 6, 14, 8, 5, 1, 19, 9, 23, 18, 15 and 7. In order to further pneumococcal vaccine research and reduce childhood mortality, five countries and the Bill & Melinda Gates Foundation established a pilot Advance Market Commitment for pneumococal vaccines worth US$1.5 billion. Advance Market Committments are a a new approach to public health funding designed to stimulate the development and manufacture of vaccines for developing countries.

There is currently research into producing vaccines than can be given into the nose rather than by injection. It is believed that this improves vaccine efficacy and also avoids the need for injection.

The development of serotype-specific anticapsular monoclonal antibodies has also been researched in recent years. These antibodies have been shown to prolong survival in a mouse model of pneumococcal infection characterized by a reduction in bacterial loads and a suppression of the host inflammatory response. Additional pneumococcal vaccine research is taking place to find a vaccine that offers broad protection against pneumococcal disease.