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Excerpt To the editor: We wish to call to your attention an apparent error in Figure 3 of the article "Sporadic Legionellosis in the United States: The First Thousand Cases" by England and colleagu...

A review of the medical records of 123 persons with Legionnaires' disease hospitalized in the 1976 Philadelphia epidemic showed that the manifestations of infection ranged from mild grippe to a severe pneumonia that also involved other organ systems. Early in the illness, constitutional symptoms predominated. Fever, malaise, myalgia, rigors, confusion, headache, and diarrhea were usually followed by nonproductive cough and dyspnea. Physical examination showed few abnormalities other than rales. Moderate leukocytosis with left shift, elevated erythrocyte sedimentation rate, elevation of serum levels of liver enzymes, and hematuria and proteinuria were characteristic. Chest radiograph showed patchy, often nodular, areas of consolidation. Progression of pneumonia led to respiratory failure and the need for mechanical ventilatory assistance for 19 patients; renal failure, primarily after shock, occurred in 18 persons. Twenty-six patients died. Treatment with erythromycin or tetracycline resulted in the lowest case-fatality ratios, but the associations were not statistically significant.

As of 30 September 1979, 1005 confirmed cases of sporadic legionellosis caused by Legionella pneumophila serogroups 1 to 4 in U.S. residents had been reported to the Centers for Disease Control; 19% were fatal. All but 2% of the 1005 cases were associated with pneumonia documented by chest radiograph. About 75% of the cases occurred in June through October. The risk of acquiring sporadic legionellosis was increased among males and persons 50 years or older; persons with renal disease necessitating dialysis or transplantation, with chronic bronchitis or emphysema, with diabetes mellitus, and with cancer (10 selected sites or types); persons who smoke; and persons being treated with immunosuppressive drugs. Increasing age and chronic bronchitis or emphysema were associated with increased risk of death. The sensitivity of culturing L. pneumophila from specimens positive by direct immunofluorescence was estimated to be 45%. The distribution of serogroups 1, 2, 3, and 4 of L. pneumophila in 57 fresh, not previously examined direct fluorescent antibody-positive specimens was 84%, 11%, 4%, and 2%, respectively; all 26 strains isolated from these specimens were of one of these four serogroups.

The efficacy of pneumococcal vaccine in groups of patients in the United States at high risk for pneumococcal disease was estimated by comparing distributions of serotypes of Streptococcus pneumoniae isolated from vaccinated and unvaccinated persons. Between May 1978 and March 1984, 187 blood isolates and 62 cerebrospinal fluid isolates from vaccinated patients, and 1447 blood isolates and 191 cerebrospinal fluid isolates from unvaccinated patients were serotyped at the Centers for Disease Control. The study did not include patients who were less than 2 years old or who had Hodgkin's disease, multiple myeloma, or immunoglobulin deficiency. In patients with bacteremic disease, the overall efficacy of pneumococcal vaccine was estimated at 64% (95% confidence limits, 47% to 76%); efficacy did not differ significantly with age. In persons over 65 years of age with diabetes mellitus, chronic heart disease, pulmonary disease, or no underlying illnesses, efficacy was 61% (95% confidence limits, 1% to 85%). These findings support the use of pneumococcal vaccine in selected populations in the United States.