A four-country African study of mothers with HIV giving birth in 2007 and 2008 has shown that up to half of children exposed to HIV during pregnancy and childbirth did not receive nevirapine to prevent HIV infection at the time of delivery.
Younger mothers and those who made fewer visits to the health facility before giving birth were significantly less likely to have taken a dose of nevirapine, and their infants were less likely to have received a dose of nevirapine after birth, according to results of a study published on 18 July in the Journal of the American Medical Association to coincide with the opening day of the Eighteenth International AIDS Conference in Vienna.
Calls for a greater effort to employ proven interventions in the prevention of mother-to-child transmission are prominent at this year’s International AIDS Conference.
“The virtual elimination of mother-to-child transmission by 2015 is sacrosanct,” said Michel Sidibé, Executive Director of UNAIDS, in his plenary address to the conference.
Speaking at the Children First conference preceding the AIDS conference, UNICEF’s HIV & AIDS chief said: “In 2010 the stars are aligned for the elimination of vertical transmission. We can see the pathway to make this happen by 2015. The question is, how do we get systems to work together, how do we get programmes to talk to each other?”
Experts believe that vertical transmission – transmission of HIV from mother to child during pregnancy, delivery or breastfeeding – could be virtually eliminated by 2015 if national programmes are able to implement a number of key measures:
Adopting new WHO guidelines for prevention of mother-to-child transmission to ensure that the most effective regimens are being used, and moving towards earlier antiretroviral treatment for all women who are medically eligible.
Promoting integration of HIV services, maternal-child health services and family planning in order to reduce the number of unintended pregnancies.
Prevention of HIV infection of women.
Comprehensive care for families, particularly through integration of HIV into maternal-child health services.
However the research presented today, carried out by Jeffrey and Elizabeth Stringer of the Centre for Infectious Disease Research in Zambia and colleagues in Cameroon, Ivory Coast and South Africa, shows that there is still a long way to go to achieve high levels of coverage of the key interventions.
The researchers tested umbilical cord blood samples at delivery in 27,893 randomly-selected mother-infant pairs, of which 12% were HIV-positive. Out of 3196 deliveries by HIV-positive mothers, mothers took nevirapine in 1845 cases, and both mothers and infants were dosed with nevirapine in 1725 cases.
The virtual elimination of mother-to-child transmission by 2015 is sacrosanct, Michel Sidibé, Executive Director of UNAIDS
The average coverage was 51%, and there were large variations between countries and within countries, but multivariable analysis found that location was not significantly associated with failed coverage of nevirapine.
Women under 30 were less likely to be covered by nevirapine prophylaxis, as were those who attended fewer than six antenatal clinic visits during pregnancy.
The authors say that these findings have immediate implications for counselling of young mothers, and underline the importance of repeat antenatal visits.
However they say that the underlying problem is a series of failures in the cascade of actions that are necessary for a mother to take a dose of nevirapine – or other antiretrovirals – to prevent vertical transmission.
This cascade of actions – all of them critical – consists of:
Documentation that the mother has presented to the health facility, and the opening of a health record which documents all of the subsequent critical steps in this pathway;
Offer of maternal HIV testing;
Acceptance of testing;
Giving the HIV test result to the mother and recording by the health facility;
Dispensing of maternal nevirapine or other antiretroviral regimen;
Taking nevirapine (or other antiretroviral drugs) as instructed;
Infant given nevirapine prior to discharge from hospital or within 72 hours of birth at home. The infant dose is necessary to maximise the protective effect of nevirapine prophylaxis.
A failure at any point in this pathway after documentation means that prophylaxis cannot prevent infant HIV infection.
The international comparison found large variations in performance at each stage of the cascade, suggesting that one of the most critical issues in ensuring virtual elimination of vertical transmission will be quality improvements in care at each stage at every health facility.
“Even the most potent interventions will not protect those infants who do not receive them,” the research group conclude.
But the inherent complexity of this pathway, with so many steps in comparison with initiating antiretroviral therapy for the mother, may be another strong argument for promotion the widest possible adoption of new WHO guidelines recommending treatment for mothers with CD4 counts below 350 cells/mm3.
A recently-published modelling exercise using data from a Zambian cohort estimated that 80 to 90% of vertical transmissions could be prevented if women with CD4 counts below 350 cells/mm3 received three-drug antiretroviral therapy.
Stringer EM et al. Coverage of nevirapine-based services to prevent mother-to-child HIV transmission in 4 African countries. JAMA 304 (3): 293-302, 2010.