Study On The Measles Epidemic Change And The Current Immunity Situation Of Population In Jiading District

Part 1 The incidence situation of the measles in Jiading Districtfrom 1953 to 2007[Objectives]The goal of the study is to learn about the epidemic characteristics of the measles in Jiading District,providing the basic information for studying the measles immunity situation,and prevention and control of meales.[Methods]The measles epidemic data in Jiading District from 1953 was collected and analyzed,and attention was paid to the descriptive analysis for the epidemic reporting data and the monitoring data of the measles from 1992 to 2007.[Results]There are 50594 measles cases in Jiading District from 1953 to 2007. The incidence rate from 1953 to 1965 remained at a relatively high level,the average incidence is 884.84 per 100000,and the incidence rate in 1959 achieves a peak above 3000 per 100000.The incidence rate started reducing rapidly from 1966.and the average incidence rate from 1966 to 1981 was 114.08 per 100000.But the incidence rate varied with a large scale,and the incidence rate reached a peak in 1980,achieving 606.30 per 100000.The incidence rate reduced to a low relatively level rapidly afterwards,and the average incidence rate from 1982 to 1991 was 0.62 per 100000. The total of 503 Measles cases was diagnosed from 1992 to 2007.in which 104(20.7%) were local population with the incidence rate of 1.31 per 100000,and 399(79.3%) was non-native population with the incidence rate of 9.59 per 100000. The epidemic situation presented a rising trend with the sporadic onsets predominating in that period,and the incidence rate of non-native population was higher than that of local population.The positive correlation between the measles cases and the non-native population quantity was absorbed.The local cases mainly concentrated in adults above 20 years old and 0-8 month infants,accounting for 83.65%,and the non-native cases mainly concentrated in 8-month-old to 7-year-old children and adults above 20 years old,accounting for 72.43%.In the local population, the incidence rate of the 0- year- old group infants was the highest,achieving 60.70 per 100000,and the 20- year-old group adults rank second.[Conclusions]The measles epidemic situation was well under control after the usage of measles vaccine in 1965.The epidemic situation presented a re-rise in 1992, the onset age of measles trended to be ''bidirectional shifting",low-age children and adults above 20 years old is much easier to be infected.The incidence rate of non-native population is the emphasis and difficulty of measles control and prevention in Jiading District.Part 2 The measles immunization coverage situation of the children in Jiading District[Objectives]The goals of the study is to learn about the measles immunization coverage situation of the local and non-native children in Jiading District,and to analyze the correlation between measles incidence and the immunization coverage.[Methods]To investigate the measles immunization coverage situation,the vaccination data was collected from 2003.applying the PPS sampling(the capacity proportion probability sampling,PPS) to collect 210 local children and 210 non-native children at the age of 8 months to 4 years.[Results]The measles immunization coverage rate of the local children is higher than that of the non-native children in 2003.The MV1 immunization coverage rate of 8-month-old to 4-year-old children is 98.33%in 2007.and the MV2 immunization coverage rate is 94.41%.The immunization coverage rate and the qualified rate of the local children are higher than that of the non-native children in the same age group.The average vaccination month age of the local children is 8.44 months,which of the non-native children is 9.23 months.The immunization qualified rate of MV1.MV2 of the non-native children is 92.38%and 82.91%respectively,and that of MV1.MV2 of the local children is 81.43%and 59.59%respectively.The difference of the qualified rate of MV1 between the local children and the non-native children has statistical significance.The difference of immunization constituent ratio of MV and MMR also has statistical significance.The main reasons of non-vaccination are to vaccinate ahead of time(71.43%) and unknown to the vaccination place(28.57%).[Conclusions]The immunization coverage situation presents imbalanced between the local children and the non-native children.The situation of measles vaccination in local children is better than that in the non-native children.The immunity barrier still needs to be reinforced.Health education on the Planned Immunity and vaccination in time should be strengthened.To eliminate the immunity blank,leak-check and revaccinate should be done well.Part 3 The measles immunity level of population in Jiading District[Objectives]The goal of the study is to learn about the serum antibody level of population in Jiading District,and to observe the correlations between the serum antibody level and the incidence,so as to develop the immune prevention and control aiming the high risk population.[Methods]General population:Ma Lu Town where non-native population centralizes is selected for the study site,and cluster sampling is applied for selecting local population sample and non-native population sample,considering they are in the same class and the same workshop.The sample of 8- month infants group are selected from the same EPI clinics,according to the visiting sequence.Pregnant woman:Healthy pregnant women were selected from MCH hospital in Jiading District from October 10,2007.according to the hospitalizing time order. Enzyme-linked Immunosorbent Assay(ELISA) is applied in the study.[Results]General population:There are total of 375 cases,in which 188 cases are local population,and 187 cases are non-native population.The measles antibody positive rate of population in Jiading District is 89.60%.and the difference of the positive rate between the local population and the non-native population has no statistics significance.The measles antibody positive rate of 8- month infants is the lowest in all age-groups,and that of 20-40 year-old adults is lower.The proportion of those with vaccination records in the cases of measles antibody negative is 61.54%, and it is 33.33%who have vaccination records more than one time.The positive rate is only 11.11 percent in 8-month-old infants when the time is no more than 10 days from the first-dose vaccination coverage.The difference of the positive rate between the vaccination times has statistics significance,and the positive rate rises with the vaccination times incerases.The positive antibody geometric average titer(GMT) of the local population is lower than the non-native population,and the difference has statistics significance.The difference of the antibody titer level has statistics significance among age-groups.The antibody titer level of 3-year old is the highest at 1489.29,and there is a downward trend with age,but increase suddenly in 30 to 40-year-old group.Pregnant woman:From 400 healthy pregnant women,we obtained 395 serum samples,in which 197 women are local population and 198 women are non-native population.The investigation showed that the measles antibody positive rate is 92.15%,and the rate of the antibody negative to low protection level(1:200) is 28.86%.The measles antibody positive rate of local population is higher than that of the non-native population.The antibody geometric average titer(GMT) of the local pregnant woman of antibody positive is lower than that of non-native women.[Conclusions]8-month infants and 20 year-old adults are the high risk population of the measles infection,especially that the 8-month infants without vaccination as well as before the immune response after vaccination are very susceptible to measles,so the protection for them should be strengthened.The immune failure occurs sometimes,and the vaccination quality should be improved. The measles antibody level of the pregnant woman should be improved,so as to reduce the incidence rate of infants before vaccination.Part 4 conclusions and policy suggestions[Conclusions]The epidemic situation presented a re-rise in 1992.The onset age of measles trended to be "bidirectional shifting",and children of old age group and adults above 20 years old are much easier to be infected.The immunization coverage situation presents imbalanced between the local children and the non-native children, and the measles antibody level of the pregnant woman is ineffective to prevent the incidence of infant.The immunity barriers still need to be reinforced.The non-native population is the emphasis and difficulty of measles control and prevention in Jiading District.[Policies and suggestions]Attention should be paid to the measles control and elimination.Management of the monitoring and reports of measles should be strengthened,and epidemic situation of measles should be handled in time.The study on the measles vaccination for women of child-bearing age before marriage still needs to be developed further.We should strengthen health education on measles,strengthen standard construction of EPI clinics,develop standard vaccination,and enforce quality control.To improve the implementation effect of the immunity strategy,the management of the non-native population should be strengthened.