| ObjectiveTo analyze the epidemiological characteristics of pertussis cases reported in Sanming City,understand the diagnosis and report of pertussis in Sanming medical institutions,master the pertussis antibody level in serum among the community-based populations in Sanming,and provide a basis for formulating and adjusting prevention and control strategies.MethodsThe cases of pertussis reported from 2005 to 2019 in Sanming City were collected through China Disease Prevention and Control System and their epidemiological characteristics were analyzed by descriptive methods.The medical records of 68children with cough admitted to the monitoring hospital from January 2019 to December 2019 were collected.Analyze and compare the gender,age,immunological history,clinical manifestations and case diagnosis of pertussis group and non-pertussis group.ELISA method was used to detect the antibody of pertussis toxin Ig G(PT Ig G)in community population,and then the distribution of antibody level in different areas,gender,age and immune history was analyzed and compared.Results(1)Routine surveillance:from 2005 to 2019,the average annual incidence of pertussis in Sanming City was 0.16/100,000,presenting a sporadic state,and the incidence trend was consistent with that of the whole country.The reported cases were mainly clinically diagnosed cases,accounting for 95.38%.The age ranged from 1 month to 12 years old,with a median age of 5 months,and 64.62%of them were under 1 years old.Most of them had an incomplete immunization history,81.54%of the patients didn’t complete 4 doses of whole-course immunization.The majority of the reported hospitals were Sanming First Hospital,Second Hospital and Youxi County Hospital,accounting for 73.85%.Rural areas outnumbered urban areas,accounting for 69.23%,and the peak period was from May to September.(2)Sentinel surveillance:A total of 68 monitored cases were investigated.The cases of pertussis infection accounted for 19.12%(13/68),the diagnostic report rate was 23.08%(3/13),and the misdiagnosis rate was 76.92%.The age ranged from 1month to 6 years old,and 76.92%of them were were less than 6 months old.There was a linear decreasing trend between vaccination times and detection rate of pertussis(χ~2=9.564,P=0.002).38.46%(5/13)of them had labored breathing,38.46%(5/13)had purpura,38.46%(5/13)had post-cough vomiting,and 30.77%(4/13)had sleep disturbance in the pertussis cases,and there were statistically significant differences between pertussis and non-pertussis(P=0.001,P<0.001,P=0.004,P=0.018).Multi factors Logistic regression analysis revealed that vaccinationhistory(OR=0.052,95%CI=0.007-0.378),labored breathing(OR=7.181,95%CI=1.584-32.554),post-cough vomiting(OR=1.969,95%CI=1.152-10.598)and close contact cough(OR=26.830,95%CI=5.126-140.25)were independent factors of pertussis detection.(3)Serum surveillance of community population:among the 932 subjects extracted from 2 counties,the positive rate of PT antibody against pertussis was10.30%,and there was no significant difference between regions and between men and women(χ~2=0.344,P=0.558,χ~2=0.336,P=0.562).The differences among different age groups of the positive rate of PT antibody were statistically significant(χ~2=52.260,P<0.001),with the highest among the children aged from 2 to 3(33.87%).The estimated incidence rate was 5623/100,000 among the people aged from 4 to 59,and there were statistically significant differences among different age groups(χ~2=10523.462,P<0.001),with the highest among the people aged from 5 to 6(9843/100,000).There was a statistically significant difference between the PT positive rate(9.29%)of children who received the co-purified vaccine and the PT positive rate of children who received the component vaccine(60.00%)(χ~2=42.617,P<0.001).The positive rate of Pt antibody completing the whole immunization was 32.39%,which was higher than 8.25%in the basic immunization group,and there were statistically significant differences(χ~2=18.045,P<0.001).The positive rate of PT antibody was 34.92%within 1 year after completing the whole immunization,and 7.14%,7.81%and 7.02%within 1 to 4years,respectively,and there were statistically significant differences(χ~2=28.715,P<0.001).ConclusionsThe incidence of pertussis reported in Sanming City from 2005 to 2019 was low,but both sentinel surveillance and serum surveillance indicated that the actual incidence of pertussis in Sanming City might be seriously underestimated and there was a risk of“pertussis recurrence”.The main causes for missed diagnosis might be atypical clinical symptoms,insufficient clinical diagnostic ability,imperfect diagnostic criteria and laboratory test methods.Timely and whole-course pertussis vaccination is still an effective measure to prevent and control pertussis.Relevant departments should take targeted measures to strengthen the monitoring of pertussis,further study diagnostic criteria and monitoring schemes,and timely adjust the vaccination procedures and strategies. |
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