Epidemiology of Unimmunized Children:

Transcription

1 Epidemiology of Unimmunized Children: Systematic Review of the Peer-Reviewed Literature Global Immunization Division Centers for Disease Control and Prevention Atlanta, Georgia October 29,

2 Outline Review approach Findings Undervaccinated child (missing > = 1 EPI vaccine dose) Unvaccinated child (missing all EPI doses) Limitations Conclusions 2

3 Search of Databases Initial database search filter Immunizations + low/middle income countries Based on economic status in 2004 In title, abstract, or included in key words Articles from Medline (Ovid) Non-Medline: EMBASE, Sociological Abstracts, Soc Serv Abs, ERIC, Cochrane, Web of Science, CINAHL 3

4 Article Review Secondary filter - review of titles/abstracts by one person Title: included following terms: Routine immunization (or specific EPI vaccine) Immunization (vaccination) coverage or survey Infant/child health service utilization Vaccine preventable disease Abstract (if available): mentioned reasons/factors related to child s immunization status Serological/immunological surveys, non-epi vaccines, global policy papers excluded 4

5 Article Review Final filter - each article reviewed by two persons In WHO language and in peer-reviewed journal Meets minimum study quality criteria Yes to at least 7 of 10 pre-defined quality questions Describes at least one reason/factor linked to vaccination status Discrepancies regarding relevancy assessed by independent reviewer 5

6 Analysis Abstracted information entered into qualitative analysis software Identified reasons/factors grouped into major themes (from Vaccines, 3 rd ed.) Family characteristics Parental attitudes and knowledge Immunization systems Communication and Information Coding of reasons/factors into further subgroupings 6

7 Flow chart Medline search = 9,480 Non-Medline = 6,617 Excluded as not relevant Excluded as not relevant Excluded as not relevant or duplicate Categorized as highly relevant and reviewed = 304 Categorized as highly relevant and reviewed = 303 Excluded as not relevant or as duplicate Articles included after review and meet quality criteria = 145 Articles included after review and meet quality criteria = 53 *Articles included in study = 198 *Does not include 13 articles received directly from IDRC 7

8 Relevant Articles 1 st filter 2 nd filter Final Medline 9, Non-Medline 6, Other* Total 16, *Articles received from IDRC (Canada) (in press at time of review) 8

9 Relevant Articles by Country and Year Number of articles >= 15 More articles during recent years, includes articles only through March different countries represented (9 additional regional or global articles) 9

10 Reasons: Definition of Categories* Immunization System Access and vaccine service availability Use of all opportunities Cost and service quality Health worker knowledge Communication/Information Media messages regarding vaccinations Community involvement in EPI Trust in health service provider Family Characteristics Education level (of mom and dad) Family size Income, occupation Ethnicity/language group Parental Attitudes/Knowledge Perceived benefit of vaccines Perceived disease threat Group pressure for or against vaccinations *From Vaccines, 3rd edition 10

11 Reasons for being undervaccinated as reported from reviewed articles (21%) (44%) (7%) (28%) % based on 887 reasons abstracted from 209 relevant articles 11

12 Immunization System Major findings Access and/or distance to services Missed opportunities Not having vaccination card Vaccinator absent Wrong contraindication Curative services only Low health worker experience/knowledge Unavailable vaccines or supplies Reported Immunization System related reasons =

13 Communication/Information Major findings Lack of media/radio exposure Poor communication due lack of trust or rude provider Inadequate or incorrect information from health care worker Lack of community involvement in EPI Reported Communication/Information related reasons = 58 13

14 Family Characteristics Major findings Low education level or illiterate caregivers Most frequently mother s education level Low socio-economic status Living in large family/having older sibs Belonging to minority group/low caste or being a migrant Reported Family Characteristics related reasons =

15 Parental Attitudes/Knowledge Major findings Caregivers lack general knowledge about immunizations Caregivers have misconceptions or fear of vaccinations Low motivation among caregivers Against vaccinations due to religious/traditional beliefs Being female Reported Parental Attitudes/Knowledge related reasons =

16 Other Reasons/Factors Infrequently reported but of high public health importance Lack of physician referrals for vaccinations Seasonal migration linked to being undervaccinated Children of HIV+ caregivers Gender of health care worker Lack of lady health workers Children of unmarried or older mothers Limited family discussions on immunizations 16

17 Relevant Articles by Country and Year: Unvaccinated Child 6 Articles 1 Article Articles from Bangladesh, Benin, India, Nepal, Nigeria, Turkey, and Vietnam 17

18 Reasons for being unvaccinated as reported from reviewed articles (27%) (12%) (6%) (55%) % based on 33 reasons abstracted from 12 articles on unvaccinated children 18

19 Reasons for being unvaccinated Major findings Religious beliefs Vaccinations are not necessary Being female child Concerns regarding vaccine safety Distance to health facility Low SES and living in rural/remote area Parental Attitudes and Knowledge *Of total 33 reasons listed 19

20 Reasons by Major Categories over Time % based on 887 reasons abstracted from 209 relevant articles 20

21 Limitations Potential research and/or publication bias Reporting only reasons/factors investigated Some papers reporting many reasons/others a few Reviewers of articles varied May have introduced some bias during identification of relevant articles Reasons/factors reported from different study types Difficult to quantify review findings Coding of reasons/risk factors has limitations (many reasons cross-cutting, etc.) 21

22 Conclusions Undervaccinated children linked to similar reasons across time and region Access due to geographic barriers (living in remote/rural areas, clinic too far away) Missed opportunities to vaccinate Low parental education level and knowledge of vaccinations Unvaccinated strongly associated with beliefs and perceptions Role of immunization systems and community involvement in EPI are key for both Work identifies general patterns, some gaps, and additional hypotheses 22

23 Acknowledgements Dr. Jeanette Rainey Dr. Vance Dietz Margaret Watkins Tove Ryman Paramjit Sandhu Anne Bo Aaron Wallace Alice Pope Dr. Karen Hennessey Dr. Terri Hyde Gal Frenkle Stephanie Clayton Rachel Lang-Balde Aissata Coulibaly International Development Research Center, Canada 23

24 Thank you! 24

25 Excluded Articles From 304 Medline and 303 Non-Medline articles Excluded following full review 25

26 Study Quality Criteria 1) Study question/hypothesis/purpose of the project defined 2) Target population defined 3) Methods included 4) Recruitment/sampling scheme described 5) Analyses described 6) Source of vaccination information 7) Data/results presented 8) Findings compared to other studies 9) Limitations addressed 10) Major conclusion described Inclusion = 70% (yes to any 7 of these 10 items) 26