The rates of morbidity and mortality due to influenza and pneumococcal diseases are high among persons with underlying medical conditions; thus, influenza and pneumococcal polysaccharide vaccines are recommended for those with cardiac disease, diabetes mellitus, chronic obstructive pulmonary disease, and other chronic illnesses. For the same reasons, influenza vaccine is recommended for pregnant women and for persons with asthma. Health care workers are at high risk for acquiring and transmitting hepatitis B, measles, varicella, and influenza; hence, vaccination against these diseases is recommended.