In spite of antibiotic treatment, mortality due to pneumonia caused by Streptococcus pneumoniae is still considerable and it is related to the presence of bacteremia. Prophylaxis with 23-polyvalent anti-pneumococcus vaccine would prevent severe processes in high risk populations. We present in this work the current status of our knowledge about this vaccine, regarding its efficacy in preventing bacteremia, economic cost, and secondary effects, we point out the indications of this vaccine according to IPAC (Immunization Practices Advisory Committee) and those special situations which modify prophylaxis (pregnancy, revaccination and massive immunizations) are discussed.