Clinical effectiveness, policies, and practices for influenza and pneumococcal vaccines.

Pneumococcal disease and influenza impact public health considerably. S pneumoniae probably accounts for almost 14,000 deaths and more than 23,000 admissions to National Health Service hospitals per annum. Influenza epidemics occur frequently and unpredictably with the potential to inflict morbidity and mortality on a massive scale. Both diseases pose maximum risks to persons with underlying chronic illnesses. Assessing the effectiveness of pneumococcal and influenza vaccines presents complex methodological problems. However, despite these difficulties, a body of evidence has accumulated suggesting that pneumococcal vaccines offer substantial protection against both bacteremia and pneumonia among healthy low-risk adults, but only against bacteremia in those considered high-risk. There is now strong evidence that the influenza vaccine protects high-risk patients from both hospitalization and death. Although most European countries now have national guidelines for vaccination of high-risk patients, both vaccines remain underused in modern clinical practice mainly due to poor organization.