Abstract:

Objective To investigate the epidemiology of pertussis in the children with protracted cough in Jinan.Methods Outpatients and inpatients with protracted cough visiting the Department of Respiratory of Jinan Children′s Hospital from January 1 to December 31 2015 were recruited to receive pertussis serum antibody and PCR detection. Information about the age of pertussis diagnosis, vaccination, season, clinical characteristics and prognosis was analyzed.Results Of 3 068 suspected cases with pertussis, 657 (21.4%) cases were clinically diagnosed as pertussis, of them, 545 (83.0%) cases were diagnosed by pertussis serum antibody and/or PCR. 247 (22.6%) cases aged from 0 to 3 months, 199 (18.9%) aged from 3 months to 1 year, 168 (19.8%) aged from 1 to 7 years, 43 (58.1%) aged from 7 to 14 years. The diagnostic rate in children aged from 7 to 14 years was significantly higher than other children. The vaccination rate in children aged from 3 months to 1 year with pertussis or non-pertussis was 45.7% (91/199) and 73.7% (622/856), and the vaccination rate was 73.2% (123/168) and 97.0% (658/678) in children aged from 1 to 7 years. The vaccination rates between children aged from 7 to 14 years with pertussis and non-pertussis were similar (41/43 vs 29/31). PCR testing was positive in 545 cases (17.8%), of them, 372 cases (12.1%) with positive serum antibody. The number of pertussis cases increased from May, with high level from July to September and decreased from October to December. Twenty-nine persons in the pertussis children family had clinical symptoms, of them 9 cases and their parents both with positive serum antibody or PCR results, 6 children were clinically diagnosed with negative but whose parents with positive serum antibody or PCR results. Of 657 children with clinical diagnosis, 215 (32.7%) had breathing, 298 (45.4%) with fever. Six cases died from pertussis encepholopathy (3 cases), asphyxia (1 case), heart failure (1 case), persisting mechanical ventilation (1 case, gave up treatment).Conclusion Pertussis accounted for a large proportion of the children under 14 years with protracted cough in Jinan, especially in the children aged from 7 to 14 years. Pertussis showed a certain seasonal trend in Jinan. To protect the prevalence of pertussis, some measures should be taken including early vaccination 2 months after birth and revaccination for the preschool children.