South African clinics already achieving zero new HIV infections in children

Maternity clinics in South Africa have the potential to achieve zero transmission of HIV from mother to child, according to a review at Tygerberg Infectious Diseases Clinic comparing infant and maternal outcomes before and after the April 2010 recommendation of lifelong antiretroviral therapy for all mothers with CD4 cell counts below 350 cells/mm³.

The study found that in 2010 no HIV transmissions occurred to 90 infants born to mothers diagnosed with HIV, compared to transmission rates of 4.6% and 7% in 2008 and 2009 respectively. This finding is comparable to transmission rates observed in resource-rich settings, investigators from Stellenbosch University report in the advance online edition of the Journal of Acquired Immune Deficiency Syndromes.

The study also found that, throughout the study period, being on antiretroviral therapy (ART) for a longer time and at a higher CD4 count before delivery was linked to a decreased risk of HIV transmission. The investigators recommend that women should be encouraged to book their first visit to the maternity clinic as soon as possible after learning they are pregnant, so that HIV testing and linkage to care can take place as early as possible in pregnancy.

Women on ART for less than eight weeks before delivery had a close to tenfold increased risk of transmitting HIV compared to women on ART for eight weeks or more; odds ratio (OR) 9.69; 95% CI: 1.66-56.58, p = 0.017.

The percentage of those on ART for more than eight weeks increased significantly from close to half (47.8%) in 2009 to nearly three-quarters (73.7%) in 2010 following implementation of the new guidelines.

However, loss to follow-up (LTFU) remained unacceptably high. Overall, close to 40% (94) were lost to follow-up within one year of starting ART, of which almost half were lost within the first eight weeks of starting ART. LTFU according to year of starting ART was 31.7%, 54.9% and 35.1% for 2008, 2009 and 2010, respectively. 

South Africa, with an estimated 5.6 million people living with HIV, continues to have the world’s highest HIV burden. In 2010, HIV prevalence among pregnant women attending antenatal care (ANC) in Cape Town Metro area was 20.2%, comparable to that of women delivering at Tygerberg Hospital.

Since 2003, implementation of PMTCT (prevention of mother-to-child transmission) interventions in all public sector antenatal service facilities in the Western Cape ensure all pregnant women with low CD4 counts are eligible for lifelong ART. In 2008, Western Cape PMTCT guidelines recommended ART for women with CD4 counts under 250 cells/mm³ or WHO Stage 4 HIV disease. 

In April 2010, revised PMTCT guidelines recommended fast-tracking the start of ART within two weeks of diagnosis for all women with CD4 counts equal to or less than 350 cells/mm³ or WHO stage 3 or 4 HIV disease.

Starting ART early in pregnancy has resulted in MTCT rates of 0 to 2.9% in resource-rich settings.

While the national PMTCT evaluation survey reported an overall MTCT rate of 3.9% (1.9-5.8) in 2010 in the Western Cape Area, there have been limited data on the performance of ART services in South Africa’s public sector. A recent study from a community-based clinic in Cape Town found a rate of 5.1% in women starting ART before delivery.

The authors evaluated the effect of the 2010 guidelines on the management of pregnant women starting ART at Tygerberg ID clinic by looking at the yearly MTCT outcomes over a three-year period.

The Tygerberg ID clinic, within the Tygerberg Academic Hospital, provides tertiary level infectious disease specialist care to half of the Western Cape Province and primary level ART care to those living in the Tygerberg sub-district. Pregnant women needing ART are referred from the Tygerberg High Risk ANC clinic and several community-based ANC clinics without ART facilities in the sub-district.

Among the 250 women 82, 71 and 97 started ART in 2008, 2009 and 2010, respectively. Baseline characteristics were similar with no statistical differences in age, parity or gestation at delivery among the cohorts.

There was a significant difference in median CD4 count at the first ANC visit (booking) in 2010 compared to 2009: 208 cells/mm³ (Interquartile range IQR:138-270) and 157 cells/mm³ (IQR: 104-206), p<0.001, respectively.

Median gestation at the start of ART decreased significantly in 2010 compared to 2009, 25 weeks (IQR: 21-31) and 30 weeks (IQR: 26-34), p<0.001), respectively with a corresponding significant increase in the time on ART before delivery.

Overall only 63% of women booked before 24 weeks gestation. While booking did improve significantly in 2010 (median of 17 weeks) 9.2% booked at 30 weeks gestation or later, so limiting the window of opportunity for ART to be effective before delivery.

Fast-tracking the start of ART made no difference in reducing MTCT. A median time of five weeks between booking and starting ART was consistent over the three-year period. In 2010, only 4% of women started ART within the specified two weeks after diagnosis.

The median time between the first visit at Tygerberg and starting ART differed significantly in 2010 compared to 2009, 1.1 weeks (IQR: 1.0-2.0) and 2 weeks (IQR: 0.8-3.8), p-0.030. Most treatment delays happened during referral to Tygerberg so identifying the bottleneck and poor integration of services is highlighted by the researchers.

“Expansion of ART sites in the community with fast-track appointments for pregnant women is recommended. Integration of services with ANC health workers starting and monitoring ART is proposed, as this would eliminate the referral process entirely.”

The longer a woman was on ART before delivery, the lower the risk of LTFU. Conversely, women starting ART at 36 weeks gestation or later, were more likely to be LTFU within a month. More than one in five (18.4%) of all LTFUs happened within 28 days of delivery.

“The magnitude of reported LTFU remains of great concern... Emphasis on retention in care should be promoted by developing efficient referral feedback systems between community ANC clinics and baby clinics and strengthening patient tracing capacity.”

The authors conclude “the positive impact of the new PMTCT programme is evident…with earlier access…the focus should shift toward educating women of the benefits of early booking to effect immediate referral to ART facilities after HIV diagnosis and ensuring women remain in care in the post-natal period.”