Mother to child transmission of HIV and its option B+ cascade predictors: An ecological study

Context: In 2013, the world Health Organization endorsed Option B plus as a strategy towards elimination of vertical transmission of HIV (human immunodeficiency virus). The purpose of the study was to examine the Option B+ trends and outcome predictors in Zimbabwe. Aims: to examine the PMTCT trends in Mashonaland East Province in Zimbabwe to determine the programmatic correlates of reduced MTCT in the first three years of introduction of PMTCT option B+. Settings and Design: Ecological study in Mashonaland East Province, Zimbabwe. Methods and Materials: The study was based on Option B plus data from the Provincial Health information system. Spatial mapping of MTCT rates was done using ArcMap 10.1. Statistical Analysis Used: Descriptive statistics and multiple linear regression of the correlates of MTCT rates using R software based on step-wise Akaike information criterion. Results: The MTCT rate for Mashonaland East was 5.3% in 2014, 5.2% in 2015 and 4.0% in 2016. The predictors for reduced PMTCT included: booking the pregnancy with a known HIV positive status (β= -0.011, SEB=0.0035), arriving in labour and delivery with unknown HIV status (β= -0.029, SEB=0.0078), testing HIV positive at retesting in labour and delivery (β= – 0.04; SEB=0.03), women with unknown HIV status within 24 months post-delivery (β= – 0.0044; SEB=0.0032) and identification of HIV exposed infants within 72 hours of birth (β= – 0.01; SEB=0.0026). Conclusions: PMTCT Option B+ was associated with a decline in MTCT rate. Intensive psychosocial support of pregnant or nursing women may facilitate reduction of MTCT rates.

Keywords: Ecological study, geospatial analysis, mother to child transmission of HIV, option B+, PMTCT cascade, predictors

Zimbabwe, among many other low-income countries, was unable to meet the goal of elimination of mother to child transmission (MTCT) of HIV by 2015.^[1],[2] In Zimbabwe, 20.5% of women are HIV positive during pregnancy. The country adopted the prevention of MTCT (PMTCT) Option B+ in 2012.^[3],[4]

In this study, we wanted to examine the PMTCT trends in one Province in Zimbabwe, after scale-up of the Option B+ program in the whole country. We also wanted to determine the programmatic, PMTCT cascade, correlates of reduced MTCT in the first 3 years of the introduction of PMTCT option B+.

An ecological design was used to guide the study. In an ecological study, an exposure or an outcome is observed and measured at the population level. Ecological studies examine group trends. This makes it easier to extrapolate to the general population at public health level. In this study, the PMTCT cascade and the ultimate MTCT rate were examined at the provincial level.

Zimbabwe has 1.5 million people living with HIV, mostly females. The country is divided into ten provinces. HIV prevalence in the provinces ranges from 10.5% to 21.5% in people aged between 15 and 49 years.^[5] Among the Provinces, The study was conducted using data from Mashonaland East Province. With a total population of 693 174 women, the Province is resident to 10.2% of all females in Zimbabwe.^[6] The prevalence of HIV in the Province, at 15.2% is only 3^rd after Matabeleland North and South Provinces. Moreover, the Province has an HIV seroprevalence of 2.3% in children aged 0–14 years; second highest prevalence by Province after Matabeleland North Province.^[5] Fortunately, the province has a high establishment of health workers; including 62 doctors, 975 nurses, 242 environmental health technicians, 26 pharmacists, and 34 laboratory workers. This results in a ratio of 0.02 doctors/1,000 people and 0.7 nurses/1,000 people.^[7] Mashonaland East Province has the highest number of women initiated on ART in ANC, compared to all other Provinces in Zimbabwe. The Province also has the highest number of HIV-exposed children’s DNA PCR (deoxyribonucleic acid polymerase chain reaction test) results given to clients.^[8] On the other hand, the province has the 2^nd highest prevalence (2.3%) of HIV among children, in the country.^[9] Thus, analysis of data from the Province can reflect the PMTCT program in the country. The population, health infrastructure, and resources for the province are summarized in [Table 1]. The figures are expressed as a percentage of the Provincial total.

We obtained data on PMTCT option B + program from the Mashonaland East Provincial Health Information System. Data which reflects the PMTCT cascade was obtained. The PMTCT cascade involves the steps undertaken by the woman and/or her HIV-exposed offspring as they receive HIV-related care.^[10] The steps include access to antenatal care by the pregnant woman, HIV testing and counseling, enrolment of the woman into PMTCT, initiation of antiretroviral (ARV) drugs by the woman and follow-up of the woman during pregnancy. After delivery, the cascade steps involve access to postnatal care, HIV prophylaxis for the child using ARV drugs, HIV testing of the child, initiating the child on ART, if positive, and finally following up the mother-baby pair on ART.^[11],[12]

Ethics

The whole study was approved by the Provincial Medical Director for Mashonaland East Province and local institutional review boards. The boards are the Joint Research Ethics Committee for University of Zimbabwe College of Health Sciences and Parirenyatwa Group Hospitals and the Medical Research Council of Zimbabwe.

Statistics

We computed descriptive statistics for the provincial PMTCT cascade steps. The outcome measure was MTCT reflected by a positive DNA PCR positive result at 6 weeks and an HIV antibody test at 18 months for the ten districts in the province. We then computed a geospatial distribution map of MTCT for the years 2014 and 2015 using ArcMap 10.1 software by esri. To obtain the predictors of MTCT, the best model was selected based on step-wise Akaike information criterion using the R Project for Statistical Computing by the R Foundation. Predictors with a P < 0.05 were considered to be statistically significant.

PMTCT Option B+ data for 2013 was only available for Marondera and Chikomba Districts. However, after the year, all the districts availed their data on the PMTCT cascade. In 2014 Goromonzi district had the greatest proportion of women, 5,444 (16.6%), who went through HIV testing and counseling (HTC) and received results. On the other hand, Seke District recorded the greatest number of women booking while already aware of their HIV positive status 668 (23.9%). Among the women 375 (18%) booked their pregnancy while already on ART. Nobody in Mudzi tested HIV positive at first test in labor and delivery. Marondera district recorded the greatest number of institutional deliveries in the Province, 4,248 (16.8%). By 14 weeks after delivery, only 3,188 (12.6%) of total institutional deliveries mothers were still exclusively breastfeeding in the whole Province. Option B+ data for the year 2014 is summarized in [Table 2].

Data for 2015 showed an extensive increase in a total number of women in the PMTCT cascade, although with a similar trend. For instance, Goromonzi still had the highest number of women, 7,533 (16.9%) who had gone through HTC and received results. Seke district had the highest number of women in the province, 600 (17.8%), booking for the first ANC visit with a known HIV status. Like what had happened in 2014, there was a gradual decline in the number of women in the later steps of the PMTCT cascade. Most institutional deliveries were recorded in Marondera district which had 5,836 (16.4%) institutional deliveries. The exclusive breastfeeding rate for the whole province was 11.09% of total institutional deliveries for the province. The PMTCT cascade data for 2015 are summarized in [Table 3].

The number of women in the PMTCT cascade was relatively constant, compared to 2015 statistics. High figures were obtained in Goromonzi and Seke districts. Mudzi district recorded favorable statistics. For example, the district had no woman testing HIV positive at retesting in labor and delivery. Women who were exclusively breastfeeding at 14 weeks postdelivery were 10.65% of total institutional deliveries. [Table 4] summarizes the PMTCT data for 2016.

While the whole province experienced a steady decline in MTCT from 5.35% to 4.04% only Chikomba and Seke districts had a reduction in MTCT rate between the years 2014 and 2016. The other districts had either an increasing or a generally constant MTCT rate. The student’s t-test results of the absolute and percentage of children testing DNA PCR positive for HIV in years 2014, 2015, and 2016 were statistically insignificant. The trends in MTCT rates in the nine districts in Mashonaland East Province are summarized in [Figure 1].

Spatial analysis of the MTCT, shown in [Figure 2], showed that the higher absolute number of MTCT was recorded in areas close to Marondera, which has the provincial health management team. However, after factoring the number of samples submitted for HIV DNA PCR tests, the MTCT rates tend to be higher in the peripheral districts. MTCT rates were highest in Chikomba, Mutoko, and Uzumba Maramba Pfungwe Districts, in 2014. However, in 2016, higher MTCT rates were confined to the Eastern Districts of Mashonaland East Province. The Districts are closer to the international Border of Zimbabwe with Mozambique. Seke and Goromonzi Districts are near Harare, the capital city of Zimbabwe.

Multiple linear regression of the PMTCT cascade predictors of MTCT showed a coefficient of determination of R² = 0.77 (F = 2.83, P > F = 0.04). This shows that the predictors could explain 77% of the variance in the MTCT rate. A step up AIC produced a final model with eight correlates of MTCT. The PMTCT cascade steps associated with increased MTCT included: the number of women who tested for HIV and received results (β =0.0017; SEB = 0.00034), initiation of ART in labor and delivery (β = 0.11; SEB = 0.028) and women testing HIV positive within 24 h postdelivery (β = 0.065; SEB = 0.014). On the other hand, booking the pregnancy with a known HIV positive status (β = −0.011, SEB = 0.0035), arriving in labour and delivery with unknown HIV status (β = −0.029, SEB = 0.0078), testing HIV positive at retesting in labour and delivery (β = −0.04; SEB = 0.03), women with unknown HIV status within 24 months postdelivery (β = −0.0044; SEB = 0.0032) and identification of HIV exposed infants within 72 h of birth (β = −0.01; SEB = 0.0026) were associated with reduced MTCT rates. An intercept of 3.75 (SE = 0.76) implied an increase in MTCT in the absence of the PMTCT cascade interventions. Step-up AIC results are summarized in [Table 5].

This study involved over 122,013 women involved in PMTCT option B+ over a period of 3 years. This was the first 3 years after scale-up of the option B+ program in Zimbabwe. The MTCT for the Province fell from 5.35% in 2014 to 5.19% in 2015 and then 4.04% in 2016. The study provides evidence that high MTCT rates are significantly associated with a number of pregnant women HIV tested the first time in ANC and received results, the number of HIV positive pregnant women initiated on ART in labor and delivery and the number of women testing HIV positive within 24 months after delivery. Previous studies showed that receipt of ART prophylaxis before delivery is associated with reduced odds of MTCT.^[13] This study further adds that HTC and subsequent receipt of results is a crucial first step toward the reduction of MTCT. While the option B+ opt-out strategy reduces structural and sociocultural barriers in HTC most women get tested, although not all of them may get the results. Initiation of ART in labor and delivery while having the potential to increase PMTCT coverage is rather late and may not pay dividends in reducing MTCT as shown in this study. A seroconversion and a concomitant initial high viral load in untreated HIV infection increase chances of MTCT.^[14]

In this study, booking the pregnancy with a known HIV positive status, arriving in labour and delivery with unknown HIV status, testing HIV positive at retesting in labour and delivery, women with unknown HIV status within 24 months postdelivery and identification of HIV exposed infants within 72 h of birth were found to be associated with reduced MTCT rates. Data from randomized controlled trial in South Carolina showed that symptom frequency, depression anger and fatigue were associated with poor HIV infection outcomes.^[15] This may indicate that living positively or a life without the stress of being aware of having HIV infection may also contribute to decreased CD4 cell count and increased viral load which increase chances of MTCT.

Exclusive breastfeeding (EBF), like in other studies, has not been associated with MTCT.^[13] This study showed that the rate of EBF at 14 weeks gradually declined from 12.6% (2014), 11.09% (2015) to (10.65%) in 2016. The figures are contrary to national estimates of all mothers which increased from 22% in 2005. The current demographic and health survey found EBF rate at 2–3 months to be 46%, falling to 20% at 4–5 months of age.^[5] A rate of 46% is similar to EBF prevalence recorded in other countries.^[16],[17] However, 10.65% is a very low figure compared to 81% recorded in a Kenyan intervention study involving women with HIV. Stigma and fear of either transmitting HIV to the child or provoking clinical deterioration due to breastfeeding^[18] might have contributed to low rates of EBF in the current study. The rates are decreasing despite continued national education about the benefits of EBF. This may be due to a mixed culture inherent in three districts close to the border with Mozambique. A qualitative study to explore why women with HIV are reluctant to exclusively breastfeed may explain the low EBF rates among women with HIV.

This study shows that the PMTCT option B+ is associated with a reduction in MTCT, better than previous PMTCT options, A and B. The regional disparities in MTCT, in Zimbabwe, may be explained by retention of the women in PMTCT. Retention has been reported to be associated with reduced MTCT.^[10] A prospective cohort of retention in PMTCT Option B Plus may clarify the variability. However, due to the test and treat approach in HIV/AIDS management the term PMTCT option B+ is gradually becoming superseded by universal ART for individuals with HIV.

PMCTC option B+ is associated with reduced MTCT. The PMTCT predictors of reduced MTCT include booking pregnancy with a known HIV positive status, arriving in labor and delivery with unknown HIV status, testing HIV positive at retesting in labor and delivery, women with unknown HIV status within 24 months postdelivery and identification of HIV exposed infants within 72 h of birth. Women who do not know their HIV status should be made aware of their increased risk of transmission to their offspring, during the period of ignorance of HIV status and psychological adjustment soon after diagnosis. Finally, areas remote from administrative centers, particularly those which are close to the international boarder, should be closely monitored and supported in their PMTCT programs as they perform poorly compared to central areas.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ATMPH.ATMPH_530_17

[Figure 1], [Figure 2]

[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]