IMMUNISATION COVERAGE AND ITS ASSOCIATIONS IN RURAL TANZANIAN INFANTS

Saturday, 22nd of March 2014

[source]Rural and Remote Health[|source]

The published reports on the vaccination status of infants in Tanzania do not provide detailed data on the infants in difficult-to-reach populations in rural, remote communities. In remote areas, and among poorer and less educated families, improving vaccination rates has been slower than in other parts of the country.

 In this report, the authors report on a retrospective study conducted to determine the vaccination rates for the individual vaccines BCG, poliomyelitis, DPT and measles and for all vaccines together (full vaccination rate) of all infants (<1 year). The report shows that vaccination rates (including fully immunized rates) are lower in rural and partially nomadic population compared to the national average. Study concludes by requesting programs to have adaptive strategies for reaching all sects of the country if vaccine preventable diseases control goals are to be achieved.  More details are accessible at:  http://www.rrh.org.au/articles/subviewnew.asp?ArticleID=2457

 

 ABSTRACT

INTRODUCTION:  In Tanzania, vaccination rates (VRs) range from 80% to 90% for standard vaccines, but little information is available about rural populations and nomadic pastoralists. This study investigates levels and trends of the immunization status of infants at eight mobile reproductive-and-child-health (RCH) clinics in a rural area in northern Tanzania (with a large multi-tribal population that has a significant population of nomadic pastoralists) for the years 1998, 1999, 2006 and 2007. In addition, the influence of tribal affiliation and health system-related factors on the immunization status in this population is analyzed.

METHODS:  Vaccination data of 3868 infants for the standard bacillus Calmette–Guerin (BCG), poliomyelitis, diphtheria, pertussis, tetanus and measles vaccines were obtained from the RCH clinic records retrospectively, and coverage for both single vaccines and full vaccination by the end of first year of life were calculated. These results were correlated with data on predominant tribal affiliation at the clinic site, skilled attendance at birth, service provision and vaccine availability as independent variables.

RESULTS:  In 1998, the full vaccination rate (FVR) across all RCH clinics was 72%, significantly higher than in the other years (1999: 58%; 2006: 58%; 2007: 57%) (p<0.0001). BCG and measles VRs were highest in 1998 and 1999, whereas VR was lowest for poliomyelitis in 1999, and for diphtheria–pertussis–tetanus in 2007 (all p<0.001). Measles VR showed a declining trend (1998: 72%; 1999: 73%; 2006: 62%; 2007: 59%) affecting the FVR, except in 1999 when poliomyelitis VR was lower (67%). FVR > 80% was only achieved at one clinic during 3 years. No clinic showed a consistent increase of VRs over time. In univariate analysis, predominant tribal affiliation (Datoga tribe) was associated with a low FVR (odds ratio (OR) 4.6 (95% confidence interval (CI) 3.8–5.5)), as were low rates of skilled attendance at birth (OR 3.6 (CI 2.9–4.4)). Other health system-related factors associated with low FVRs included interruption of scheduled monthly immunization clinics (OR 9.8 (CI 2.1–45.5)) and lack of vaccines (OR 1.2–2.9, depending on vaccine). In multivariate analysis, predominant Datoga tribal affiliation and lack of vaccines retained their association with the risk of low rates of vaccination.

CONCLUSIONS:  Vaccination rates in this difficult-to-reach population are markedly lower than the national average for almost all years and clinics. Affiliation to the nomadic Datoga tribe and lack of vaccines determine VRs in this rural population. Improvements in immunization service delivery, vaccine availability, stronger involvement of the nomadic communities and special outreach services for this population are required to improve VRs in these remote areas of Tanzania.