HIV/AIDS/STI Surveillance Report:Report Number 21

Since the first cases of Acquired Immunodeficiency Syndrome (AIDS) in Tanzania were reported in 1983, the epidemic has evolved from being a rare and new disease to a common household problem, which has affected most Tanzania families. The mainland Tanzania faces a generalized human immunodeficiency virus (HIV) and AIDS epidemic, with an estimated 6.5% of the mainland population infected with HIV (7.7% of adult women and 6.3% of adult men). Overall, 1.4 million Tanzanians (1,300,000 adults and 110,000 children) are living with HIV infection, in a total population of 41 million. The social, economic, and environmental impact of the pandemic is sorely felt as an estimated 140,000 Tanzanians have perished, leaving behind as estimated 2.5 million orphans and vulnerable children, representing approximately 10-12% of all Tanzanian children. As elsewhere in sub-Saharan African, the underlying factors of poverty, migration, marginalization, lack of information and skills, disempowerment, and poor access to services raise the risk of HIV and have an impact on the course and spread of the pandemic. Close to 85% of HIV transmission in Tanzania occurs through heterosexual contact, less than 6% through mother-to-child transmission, and less than 1% through blood transfusion. There continues to be a significant difference in the prevalence among urban (10.9%) and rural (5.3%) areas of the country. The National AIDS Control Programme (NACP) of Tanzania was founded in 1987 to champion the health sector response to the HIV epidemic. The primary objectives of the program were to reduce spread of HIV infection, screen blood supplies, enhance clinical services for HIV/AIDS patients and improve STI treatment, prevention of mother-to-child transmission (PMTCT), advocate behavioral change and conduct epidemiologic surveillance and other research. The program phases started with a two-year phase called Short Term Plan\ud (1985-1986). Subsequent phases were termed Medium Term Plans lasting for five-year periods. Through these program phases successful national responses have been identified, the most effective ones being those touching on the major determinants of the epidemic and addressing priority areas that make people vulnerable to HIV infection. These include the following; Since early eighties great efforts have been made to reduce spread of HIV infection through screening of donor blood, advocating behavioral change, condom promotion and improvement of STI treatment. In addition a number of epidemiologic surveillance have been conducted to monitor the trend of HIV infection among different subpopulations e.g. blood donors and pregnant women attending antenatal clinics. In 2004, the National Blood Transfusions Services (NBTS), which is a centralized system of coordinated blood transfusion services, was established. The NBTS is responsible for collection, processing, storage and distribution of safe blood and blood products to health facilities. At the moment NBTS coordinates eight zonal blood transfusion centers, namely Lake Zone-(LZBTC) in Mwanza region, Western-(WZBTC) in Tabora, Northern (NZBTC) in Kilimanjaro region, Eastern (EZBTC) in Dar es Salaam, Southern highlands (SHZBTC) in Mbeya, Southern (SZBTC) in Mtwara and Zanzibar and a military zone –Tanzania People’s Defence Force (TPDF). Since the establishment of NBTS, donated blood in the eight zones is systematically screened for HIV, hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis. The National HIV Care and Treatment Plan (NCTP) was launched in October 2004, with the main focus of a rapid scaling up of HIV care and treatment services, aimed at having more than 400,000 patients on care and treatment by the end of 2008 and, at the same time, follow up disease progression in 1.2 million HIV+ persons who are not eligible for ntiretroviral therapy (ART). Prevention of Mother to Child Transmission of HIV (PMTCT) services were established in 2002 , providing a package of services that include: counseling and testing for pregnant women; short-course preventive ARV regimens to prevent mother-to-child transmission; counseling and support for safe\ud infant feeding practices; family planning counseling or referral; and referral for long-term ART for the\ud child. This report which covers the NACP activities through December 2008 has been arranged in five chapters and is intended for various stakeholders, primarily those working within the health sector.\u

Impact of Age and Sex on CD4+ Cell Count Trajectories following Treatment Initiation: An Analysis of the Tanzanian HIV Treatment Database.

OBJECTIVE: New guidelines recommend that all HIV-infected individuals initiate antiretroviral treatment (ART) immediately following diagnosis. This study describes how immune reconstitution varies by gender and age to help identify poorly reconstituting subgroups and inform targeted testing initiatives. DESIGN: Longitudinal data from the outpatient monitoring system of the National AIDS Control Program in Tanzania. METHODS: An asymptotic nonlinear mixed effects model was fit to post-treatment CD4+ cell count trajectories, allowing for fixed effects of age and sex, and an age by sex interaction. RESULTS: Across 220,544 clinic visits from 32,069 HIV-infected patients, age- and sex-specific average CD4+ cell count at ART initiation ranged from 83-136 cells/mm3, long term asymptotic CD4+ cell count ranged from 301-389 cells/mm3, and time to half of maximal CD4+ reconstitution ranged from 3.57-5.68 months. CD4+ cell count at ART initiation and asymptotic CD4+ cell count were 1.28 (95% CI: 1.18-1.40) and 1.25 (95% CI: 1.20-1.31) times higher, respectively, for females compared to males in the youngest age group (19-29 years). Older patients started treatment at higher CD4+ counts but experienced slower CD4+ recovery than younger adults. Treatment initiation at greater CD4+ cell counts was correlated with greater asymptotic CD4+ cell counts within all sex and age groups. CONCLUSION: Older adults should initiate care early in disease progression because total immune reconstitution potential and rate of reconstitution appears to decrease with age. Targeted HIV testing and care linkage remains crucial for patient populations who tend to initiate treatment at lower CD4+ cell counts, including males and younger adults

Correction: Impact of Age and Sex on CD4+ Cell Count Trajectories following Treatment Initiation: An Analysis of the Tanzanian HIV Treatment Database.

[This corrects the article DOI: 10.1371/journal.pone.0164148.]

Demographic characteristics and follow-up data of analyzed patients.

<p>Demographic characteristics and follow-up data of analyzed patients.</p

Asymptotic model diagram.

<p>Schematic diagram of the negative exponential asymptotic model of CD4+ cell recovery. Int, Asym and the half life (<i>t</i>_50%) represent the CD4+ cell count at initiation of antiretroviral treatment, the asymptotic CD4+ cell count and the time to reach 50% of the maximal CD4+ recovery, respectively.</p

Estimated effects of age and sex on CD4+ cell count response to treatment.

<p>Points reflect fixed effects parameters estimated from a hierarchical asymptotic nonlinear mixed effects model with error bars indicating 95% confidence intervals. Numerical values given in Table C in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164148#pone.0164148.s001" target="_blank">S1 File</a>.</p

Initial CD4+ cell count and asymptotic CD4+ cell count by age and sex.

<p>For each sex and age grouping, these panels show estimated asymptotic CD4+ count versus estimated CD4+ count at treatment initiation, as fitted in the best fit asymptotic non-linear mixed effects regression model of CD4+ counts over time for patients within the outpatient monitoring system of the National AIDS Control Program in Tanzania. Each circle represents one patient. Blue lines show fitted linear regressions with value in bottom right of each panel showing the R² for this correlation.</p