The Surveillance and Epidemiological Analysis of Streptococcus Pneumoniae Infection, Category Four Communicable Disease, in Taiwan

Streptococcus pneumoniae is a common pathogen for pneumonia, septicemia and cerebral meningitis. These diseases are usually seen in children less than 2 years old and senior people older than 65 years old. The infection of this pathogen may cause severe result, even death, while the immune system is compromised. National-wide data and epidemiological analysis for this disease are absent in Taiwan, with only few reports from local hospitals, which resulted in unclear understanding of the national epidemiologic situation and put limitations on the development of immunization policy. This disease was announced as a category four communicable disease in Taiwan on October 15, 2007. Local medical institutions should follow the Communicable Disease Prevention Act, which can improve our understanding of the epidemiologic situation in Taiwan. Based on the analysis result, the male and female ratio of the confirmed cases was 2:1. In terms of age, most cases were less than 4 years old and older than 50 years old, which form a V shape distribution. The mortality rate increased with age. The cases reached the annual peak in March and then decreased gradually, and lowest case number occurred in July. It was suspected that spring and winter were the preferred seasons for this disease. Geographically, most of the confirmed cases were distributed in the counties with large populations. However, the morbidity was higher in the counties with smaller populations, such as Hua-Lien. The bacterial strains from most of the cases were 14, 3, 6B, 6A, 19A, 19F, 23A and 23F. The protection rate of the 23-valent vaccine were 89.1%, 79.1% and 79.6% for 2 to 4 years old, 65 years old and above, and 75 years old and above, respectively; the protection rate of the 7-valent vaccine were 74.5% and 69.3% for less than 2 years old and 2 to 4 years old, respectively. Pneumonia was the most common complication. Other complication included septicemia, cerebral meningitis, bacteremia and peritonitis. The percentage of subclinical diseases increased with age. The results of this study may provide epidemiologic data for treptococcus pneumoniae infection in Taiwan, demonstrate the Simportance of monitoring work, and offer a reference for future immunization policy.