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Preventing Mother to Child Transmission of HIV
What is Mother to Child Transmission?
Is MTCT a Major Problem?
How can MTCT be prevented
International Initiatives to Prevent Mother to Child
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Mother to child transmission (MTCT) is when an HIV
positive woman passes the virus to her baby. This can occur during
pregnancy, labour and delivery, or breastfeeding. Without treatment,
around 15-30% of babies born to HIV-positive women will become
infected with HIV during pregnancy and delivery. A further 10-20%
will become infected through breastfeeding.
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In 2004, around 640,000 children under 15 became
infected with HIV, mainly through mother to child transmission (MTCT).
About 90% of these MTCT infections occurred in Africa where AIDS is
beginning to reverse decades of steady progress in child survival.
In high income countries MTCT has been virtually eliminated thanks
to effective voluntary testing and counselling, access to
antiretroviral therapy, safe delivery practices and the widespread
availability and safe use of breast-milk substitutes. If these
interventions were used worldwide, they could save the lives of
thousands of children each year.
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A four-fold strategy is needed to prevent MTCT: that
is to prevent babies from acquiring HIV from their infected mothers.
• Prevention of HIV among prospective parents
• Prevention of unwanted pregnancies among
HIV-positive women
• The care and treatment of HIV-positive pregnant
women
• Preventing the transmission of HIV from
HIV-positive mothers to their infants during pregnancy, labour,
delivery and breastfeeding.This is the most important strategy and
can be achieved by the use of antiretroviral drugs, safe feeding
practices and the prevention of malaria in HIV infected pregnant
women.
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It was first found that the antiretroviral
zidovudine could reduce MTCT over ten years ago. Since then new
drugs and drug combinations have been developed. Currently, there
are many different drug regimens available and their use depends on
a number of factors, including cost. The regimens can be divided
into those that are used as part of longer-term treatment for the
mother (long-term treatments) and those that are used only to
prevent MTCT (short course treatments).
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The most basic short course regimen is single dose
nevirapine. Between 1997 and 1999 the HIVNET 012 study in Uganda
found that single dose nevirapine given to the mother at the onset
of labour and to the baby after delivery greatly reduced MTCT rates.
As it is administered only once to the mother and baby, it is easier
to use and less expensive than other antiretroviral drugs used to
prevent MTCT of HIV.
Over the past 2 years there has been mounting
evidence that long-term use of nevirapine causes liver damage. At it
most serious symptomatic nevirapine liver toxicity may progress to
liver failure and death. HIV positive people with a CD4 + cell count
below 250 have an increased risk of liver problems, and women have a
higher risk than men. So HIV positive women with CD4 + cell counts
below 250 are particularly at risk of suffering liver damage from
using nevirapine as part of combination therapy.
Although these side effects have only been linked to
the long-term use of nevirapine, in mid December 2004 a story
appeared in the press alleging that side effects from single dose
nevirapine had been covered up. The story was actually referring to
a disagreement about whether procedural problems with the Ugandan
study meant that the results were scientifically invalid, not that
the Ugandan study found side effects from single dose nevirapine and
tried to cover them up, as was reported. Even if the study had been
invalidated, there have since been two other major studies of single
dose nevirapine, confirming its effectiveness in reducing MTCT and
showing no evidence of serious side effects.
The biggest concern about the use of single dose
nevirapine is resistance. Studies have found that single dose
nevirapine can compromise a subsequent response to ART with
nevirapine or efavirenz (a related drug). This could have serious
consequences for future antiretroviral treatment of mothers and
infants using nevirapine or efavirenz and for preventing MTCT by
using nevirapine in future pregnancies. There is also evidence that
if a mother develops nevirapine resistant HIV, this can be passed
through breast milk to her baby.
Because of these concerns, there is now a general
agreement that, single dose nevirapine should only be used when no
alternative MTCT drug regimen is available. If possible, nevirapine
should be used in combination with other drug(s) to prevent
resistance problems and decrease MTCT rates even further. However,
nevirapine is the only single dose ART available to prevent MTCT.
Other "short course" treatments require women to take ARTs during
and after pregnancy as well as during labour and delivery. This
means they are much more expensive and difficult to implement in
resource poor settings, compared to nevirapine that can be used with
little or no medical supervision at all. So, for now, single dose
nevirapine remains the best choice for preventing MTCT in regions
where medical resources are limited.
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One example of a longer "short-course" regimen is
the combination of AZT and 3TC during labour and AZT and 3TC for one
week postpartum for mother and infant. Another is AZT from 28 weeks
of pregnancy plus single dose nevirapine at the onset of labour for
the mother and a single dose of nevirapine for the infant within 72
hours of birth plus one week of AZT.
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In high-income countries the recommended treatment
regimen for preventing MTCT is triple combination therapy that
includes AZT. As well as preventing MTCT, this treats the mother's
HIV too. If a woman is already on ART when she discovers that she is
pregnant, she may be advised to change to different drugs. Certain
antiretroviral drugs, such as efavirenz, are not used during
pregnancy as they may cause foetal abnormalities. Women who are
diagnosed as HIV positive during pregnancy may choose to start ART
after the first trimester to reduce the risk of any possible side
effects from the antiretroviral drugs.
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A number of studies have shown that the protective
effect of the various drug regimens is diminished when babies
continue to be exposed to HIV through breastfeeding. This underlines
the substantial risk of HIV transmission during breastfeeding which
can greatly erode the short-term benefit of drugs to prevent MTCT of
HIV.
Up to 20% of infants born to HIV-positive mothers
may acquire HIV through breastfeeding. An HIV-positive mother should
be counselled on the risks and benefits of different infant feeding
options and should be helped to select the most suitable option for
her situation. The use of infant formula can be problematic, and it
may be neither feasible or safe. However, breastfeeding may cause
the child to become HIV positive, which may also result in illness
and death.
The use of infant formula means the baby is not
receiving the special vitamins, nutrients and protective agents
found in breast milk. And the cost of infant formula often puts it
beyond the reach of poor families in reource poor countries, even
when the products are widely available. Many women also lack access
to the knowledge, potable water and fuel needed to prepare
replacement feeds safely, or simply have no time to prepare them. If
used incorrectly - mixed with unsafe water, for example, or
over-diluted - a breast milk substitute can cause infections,
malnutrition and even death. Furthermore, if a mother chooses not to
breastfeed in settings where breastfeeding is the norm, this may
draw attention to her HIV status and invite discrimination, violence
or abandonment by her family and community.
For HIV-positive women who choose to breastfeed,
exclusive breastfeeding (as opposed to "mixed feeding" -
breastfeeding mixed with bottle feeding of water or formula, or
providing other foods) is recommended for the first months of an
infant's life, and should be discontinued once an alternative form
of feeding becomes feasible. This is because mixed feeding may
increase the risk of HIV infection. Indirect evidence suggests that
keeping the period of transition from exclusive breastfeeding to
alternative feeding as short as possible may reduce that risk.
Unfortunately, the best duration for this is not yet known and may
vary according to the infant's age and/or the environment.
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Malaria is endemic in regions such as Sub Saharan
Africa, Central and South America and Asia. It is a major public
health problem in Sub Saharan Africa, where 90% of all malaria cases
occur each year. HIV positive pregnant women are more likely to be
infected with malaria than HIV negative pregnant women, possibly due
to HIV impairing the body's immune response to malaria. Women who
are infected with both HIV and malaria have an increased chance of
passing HIV to their baby. So, anti-malarial drug treatment during
pregnancy is an important part of preventing MTCT and has been
implemented in some MTCT programmes. The drug
sulfadoxine-pyrimethamine (SP) is most commonly used to
prevent/treat malaria, as it is safe to take throughout pregnancy.
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Transmission of HIV
There are a number of large-scale international
initiatives to prevent MTCT of HIV. These include:
1. President Bush's International Mother and Child
HIV Prevention Initiative, now included in PEPFAR
2. USAID's Efforts to Prevent Mother-to-Child
Transmission of HIV
3. The Elizabeth Glaser Paediatric AIDS Foundation
Call to Action Project
4. The UN Interagency Task Team on MTCT
5. MTCT-Plus
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On June 19th 2002, President Bush announced a new
$500 million International Mother and Child HIV Prevention
Initiative to prevent the transmission of HIV from mothers to
infants and to improve health care delivery in Africa and the
Caribbean.
Through a combination of improving care and drug
treatment and building healthcare delivery capacity, the initiative
has the target of reaching up to one million women annually and
reducing MTCT by 40% within 5 years or less in twelve African
countries and the Caribbean.
Between October 2002 and March 2004 the US
government provided $143 million. From FY 2005 both funding and
activity are to be included in the President's Emergency Plan for
AIDS Relief (PEPFAR). PEPFAR intends to rapidly expand the programs
started by the International Mother and Child HIV Prevention
Initiative by:
• Scaling up existing MTCT programs by rapidly
mobilizing resources.
• Providing technical assistance and expanded
training for health care providers.
• Strengthening the referral links among health care
professionals.
• Ensuring the effective supply chain management of
the range of MTCT-related products and equipment.
• Expanding MTCT programs to include HIV treatment
for HIV infected mothers and other members of the child's immediate
family.
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The U.S. Agency for International Development has
been committed since 1999 to helping the millions of women and
families already infected with HIV reduce the likelihood of
transmitting HIV to their infants. In coordination with other US
government agencies, USAID focuses on a comprehensive approach to
preventing MTCT which includes improvement of antenatal services,
HIV voluntary counselling and testing services and short-course
antiretroviral for HIV infected pregnant women. It also includes
counselling and support for safe infant feeding and strengthened
health and family planning.
USAID provides a comprehensive package of MTCT
interventions in:
Ethiopia, Guyana, Haiti, Kenya, Mozambique, Namibia,
Nigeria, Rwanda, South Africa, Tanzania, Uganda, Zambia.
A number of these countries are the same ones where
PEPFAR is taking place and it is not clear to what extent there is
an overlap.
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The Elizabeth Glaser Paediatric AIDS Foundation
initiated the Call to Action Project in September 1999 to help
reduce MTCT in resource poor countries. The CTA is a public-private
partnership that receives funding from both private sources such as
the Gates Foundation and government grants.
CTA has worked or is now working at approximately
400 sites in 19 countries worldwide. These are: Angola, Cameroon,
Congo, Dominican Republic, Georgia, Honduras, India, Kenya, Malawi,
Mozambique, Russia, Rwanda, South Africa, Swaziland, Tanzania,
Thailand, Uganda, Zambia and Zimbabwe.
The Foundation joined up with USAID in 2002 to
rapidly expand MTCT prevention programs. Programs that were funded
by USAID are now funded by PEPFAR and CTA sites are still supported
with private funding.
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The UN Interagency Task Team on MTCT involves
UNICEF, UNFPA, WHO, the World Bank and the UNAIDS Secretariat and
works with the governments of various developing countries to set up
MTCT programs.
Between April 1999 and July 2002, the support
provided by this program reached almost 600,000 pregnant women in
antenatal care centres. Treatment with antiretroviral drugs was
provided to more than 12,000 HIV positive women.
As of 2004, support has been provided to 226
programme sites in 16 countries. The countries are Belarus, Botswana
Burundi, Cambodia, Cote d'Ivoire, Honduras, India, Kenya, Malawi,
Myanmar, Rwanda, Tanzania, Uganda, Zambia and Zimbabwe. In future
support will be extended to Cameroon, Central African Republic,
Mozambique, Namibia, Nigeria and Vietnam.
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The MTCT-Plus Initiative was established in 2002. It
is coordinated by the Mailman School of Public Health at Columbia
University, and supports the provision of specialized care to HIV
infected women, their partners and their children who are identified
in MTCT programs.
It provides operational funding, medications,
training and technical assistance at 12 sites throughout sub-Saharan
Africa and one site in Thailand.
Funding for the initiative is provided by a group of private
foundations, including the Gates Foundation, the Kaiser Family
Foundation and the Rockefeller Foundation. They also receive funding
from USAID.
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The Global Fund is a public-private partnership that
distributes grants to 96 countries worldwide to fund HIV/AIDS
prevention and treatment programmes. Grants are distributed over two
years and most countries use the grants to fund prevention of MTCT
programmes. Some examples are:
• India where MTCT programs will be extended from
125 to 450 health care centres.
• Haiti where PMTCT programs will be extended to
reach 12,000 HIV positive pregnant women per year.
• Ghana where MTCT prevention programs will be
provided to 600 mothers per year.
• Thailand where PMTCT programs are to be expanded
so 19920 HIV+ babies, mothers and their partners will receive ART.
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