Objective: To understand the epidemiological characteristics of a pertussis outbreak in Guangzhou, so as to provide references for outbreak response and prevention strategies. Methods: From April 5 to June 9, 2024, case screening was conducted among 246 preschool children, 35 staff members, and one full time school nurse in a kindergarten in Guangzhou based on case definition. Field epidemiological investigation methods were employed to collect relevant information, and screening samples were collected from individuals involved in the outbreak. The clinical manifestations, epidemiological characteristics, and risk factors for transmission of the outbreak were analyzed, with rate comparisons performed using the χ 2 test. Results: There were a total of 15 confirmed cases of pertussis in the kindergarten. The main clinical manifestations included intermittent cough in 14 cases ( 93.33 %), sputum production in 5 cases (33.33%), fever in 2 cases (13.33%), paroxysmal spasmodic cough in 1 case (6.67%), and vomiting in 1 case (6.67%). There was no statistically significant difference in the reporting rates of interrupted cough symptoms between pertussis cases (93.33%) and non pertussis cases (92.86%)( χ 2=3.74, P >0.05). The cases were aged 4-5 years, including 5 males and 10 females. The interval between symptom onset and diagnosis ranged from 2 to 25 days, with a median of 10 days. The outbreak involved two classes, with attack rates of 48.28% and 3.45%, respectively. Laboratory testing confirmed 14 close contacts positive for Bordetella pertussisnucleic acid. Among close contacts, only one received prophylactic medication as required. Conclusion The outbreak is a pertussis outbreak in a kindergarten caused by Bordetella pertussis infection, demonstrating distinct temporal and spatial clustering characteristics.

Objective:To analyze the immunization status of routine vaccines for children aged 0-7 years old with special health status in Tianhe District, Guangzhou City, from 2023 to 2024.Methods:From April 2023 to March 2024, 42 vaccination units in Tianhe District, Guangzhou, were organized to collect data on diseases and vaccination history of children with special health status. Vaccination rates were calculated, and multivariate logistic regression models were used to explore the impact of special health status on vaccination rates.Results:A total of 1 976 children aged 0-7 years old with special health status were included, with an average of (1.26±0.58) diseases per participant. The average number of vaccine doses administered for routine immunizations was (14.29±4.27), and the full vaccination coverage was 72.76%. The vaccination rate of 10 doses in the immunization program vaccine was less than 90.00%. The timely rate of the first dose of hepatitis B vaccine (HepB1) was 74.14%, and that of the first dose of measles vaccine (MCV1) was 63.93%. Compared with children with infectious diseases, those with neonatal diseases were more likely to miss the third dose of poliomyelitis vaccine (PV3), MCV1 and the second dose of Group A meningococcal polysaccharide vaccine (MPSV-A2). Those with neuromuscular system diseases were more likely to miss PV3, MPSV-A2 and the first dose of Japanese encephalitis vaccine, live (JE-L1). Those with congenital heart disease were more likely to miss PV3, the third dose of diphtheria tetanus-acellular pertussis vaccine (DTaP3), MCV1, MPSV-A2, and JE-L1. Those with hematological disorders were more likely to miss PV3, MCV1, MPSV-A2, and JE-L1. Those with genetic diseases were more likely to miss MPSV-A2. Those with comorbidities were more likely to miss MCV1 and MPSV-A2. Those with neonatal diseases, neuromuscular system diseases, congenital heart disease, hematopoietic system diseases, genetic diseases, or comorbidities had difficulties in completing the full vaccination process.Conclusion:Children with special health conditions have lower rates of routine immunization and timely vaccination. More measures are needed to improve vaccination rates.

Objective:To analyze the immunization status of routine vaccines for children aged 0-7 years old with special health status in Tianhe District, Guangzhou City, from 2023 to 2024.Methods:From April 2023 to March 2024, 42 vaccination units in Tianhe District, Guangzhou, were organized to collect data on diseases and vaccination history of children with special health status. Vaccination rates were calculated, and multivariate logistic regression models were used to explore the impact of special health status on vaccination rates.Results:A total of 1 976 children aged 0-7 years old with special health status were included, with an average of (1.26±0.58) diseases per participant. The average number of vaccine doses administered for routine immunizations was (14.29±4.27), and the full vaccination coverage was 72.76%. The vaccination rate of 10 doses in the immunization program vaccine was less than 90.00%. The timely rate of the first dose of hepatitis B vaccine (HepB1) was 74.14%, and that of the first dose of measles vaccine (MCV1) was 63.93%. Compared with children with infectious diseases, those with neonatal diseases were more likely to miss the third dose of poliomyelitis vaccine (PV3), MCV1 and the second dose of Group A meningococcal polysaccharide vaccine (MPSV-A2). Those with neuromuscular system diseases were more likely to miss PV3, MPSV-A2 and the first dose of Japanese encephalitis vaccine, live (JE-L1). Those with congenital heart disease were more likely to miss PV3, the third dose of diphtheria tetanus-acellular pertussis vaccine (DTaP3), MCV1, MPSV-A2, and JE-L1. Those with hematological disorders were more likely to miss PV3, MCV1, MPSV-A2, and JE-L1. Those with genetic diseases were more likely to miss MPSV-A2. Those with comorbidities were more likely to miss MCV1 and MPSV-A2. Those with neonatal diseases, neuromuscular system diseases, congenital heart disease, hematopoietic system diseases, genetic diseases, or comorbidities had difficulties in completing the full vaccination process.Conclusion:Children with special health conditions have lower rates of routine immunization and timely vaccination. More measures are needed to improve vaccination rates.

Objective : To observe the clearance of smear layer on the root canal wall in different action time by scanning electron microscope (SEM), and to determine the optimal amount of time using sonically activated irrigation to wash root canal in clinic. Methods: Fifty-six ex vivo human anterior teeth with single straight root canal were selected. After routine mechanical preparation, they were divided into two experimental groups according to different irrigating agents: saline group and EDTA group. Each group was assisted by VDW sonic activation EDDY. The saline group was divided into three subgroups according to the irrigating time: 5 s, 30 s and 50 s; EDTA group was divided into six subgroups according to the irrigating time: 5 s, 10 s, 20 s, 30 s, 40 s and 50 s. The control group did not undergo root canal irrigation. After irrigation, the root was cut longitudinally. The smear layer of crown, middle and apical of root canal wall was observed by SEM. Results: After irrigating for 30 seconds, there was a significant difference between the normal saline group and the control group and the 5 second group (P<0.05), and there was no difference in the middle and apical part (P>0.05). After 50 seconds, there was a significant difference in the score of the smear layer between the apical area and the other groups (P<0.05). After irrigating for 5 seconds or 10 seconds in EDTA group, there was a significant difference between the scores of the crown and middle area of the root canal and the control group (P<0.05), and there was no significant difference in the apical area (P>0.05). There was a significant difference between the 20-40 second group and the first two groups (P<0.05). There was a significant difference between the 50 second group and the other groups (P<0.05). Comparing the cleaning effect on the smear layer after 50 seconds of irrigating between the two experimental groups, the whole root canal showed significant statistical difference (P<0.05). Conclusion The EDTA-assisted sonic activated device used for 50 seconds has the best cleaning effect.