6 курс / Кардиология / Kartikeyan_HIV and AIDS-Basic Elements and Properties
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MCH, and prevention and management of STIs including HIV (Fleishman et al., 2002; Caldwell & Caldwell, 2002). Integration of HIV-related services within family planning settings is beneficial to both clients and family planning service providers. In this model, VCT services are incorporated into ongoing services provided in the family planning setting. However, it is not obligatory for the family planning service providers to provide all the VCT services. Therefore, organisations will have to decide as to which VCT-related services can be integrated in their setting. A variant of this model envisages addition of HIV counselling and testing services to existing family planning services, while VCT programmes start providing contraceptive counselling, particularly on correct and consistent use of condoms. This will address the dual risk of HIV infection and unintended pregnancy faced by women without integrating these two programmes.
21.8.1.1 – Justification for an integrated model
Both family planning and VCT have a common target group namely sexually active people, who are potentially at risk of contracting STI and HIV. Clients with STI are those who have engaged in unsafe sexual behaviour and therefore, they are vulnerable to both HIV infection and unwanted pregnancy. Family planning and VCT services require similar infrastructure because they have to maintain confidentiality and respect the client’s privacy. Integrating VCT may require minimal changes to the existing infrastructure for family planning services, which reduces the cost of establishing VCT services.
Consequent to the integration of STI services in some family planning programmes, the service providers have already been trained in assessing clients’ risks, managing STIs, and providing appropriate referrals. These skills are also required for providing VCT services. Both family planning and VCT services require the constant supply of similar services and commodities, such as male and female condoms. The same logistic system can be used to ensure the supply of other commodities such as HIV test kits. The existing family planning outreach workers such as community-based distribution agents and peer educators, can help in raising awareness about HIV and promote VCT services in the community. Integration of VCT in family planning setting may help in community approval of taking the HIV test as “normal” and ultimately, the stigma associated with HIV infection may diminish. Family planning clinics are accessible and already serve large sections of the population. Increased involvement of males in contraception and other family planning services is a possible outcome of provision of VCT services (UNFPA, 2002).
The programme for PMTCT alone cannot meet the goals for reducing HIV infection in infants. Use of condoms can prevent HIV infections in uninfected women and prevent unwanted pregnancies in women living with HIV (WHO/UNFPA, 2006). Family planning services in sub-Saharan Africa have been found to be more cost-effective in PMTCT of HIV than the provision of nevirapine (Sweat et al., 2004). An expenditure of US$45,000 to increase contraceptive services would prevent 88 HIV-positive births whereas for the same cost, provision of nevirapine would prevent only 68 such births (Reynolds et al., 2006).
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21.8.1.2 – Potential challenges in integration
Programme managers should be vigilant about the potential challenges associated with integration of VCT in family planning settings, so that they can take these into account during the planning stage itself. Family planning clients may perceive a reduction in quality of family planning services, as a result of introduction of VCT services. For maintaining quality of family planning services after integrating VCT, it is essential to identify managerial capacity and requirement of financial and other resources. If the demand for VCT services is high, the existing family planning personnel who take on counselling duties may have an increase in workload. This problem is overcome by providing adequate training to the existing staff and by hiring more staff, if necessary. VCT counsellors should discuss sexual behaviour in detail and not just focus on contraceptive methods. With adequate training, counsellors can focus on STI/HIV and family planning issues. Non-health workers (people living with HIV/AIDS, social workers, and volunteers) have a role in VCT activities such as outreach education and counselling. In order to overcome the stigma attached to HIV, the family planning clients and the community should be informed about HIV infection and HIV testing (UNFPA, 2002).
21.8.2 – Other Models
Integrating family planning services with the ongoing services for PMTCT in 14 high-prevalence countries could double the number of HIV-positive births averted in addition to saving women’s lives and averting child deaths (Stove et al., 2003). Provision of HIV counselling along with family planning counselling in antenatal and postnatal care settings would help pregnant women in avoiding infection and help in identifying HIV-infected pregnant women (Best, 2004).
Among other suggested models are free-standing services, private sector models, and home-testing (FHI, 2002; WHO/UNAIDS, 2001). Outreach efforts and social marketing are also useful (Boswell & Baggaley, 2002). Surveys in many countries reveal that youth prefer VCT along with other youth-friendly services such as skill building courses and sports activities. Innovative approaches are necessary to reach groups such as pregnant women, out-of-school youth, and IDUs. More information is needed on coping mechanisms in persons who test HIV positive, with whom they share HIV test results, who provides emotional support, and long-term outcomes of VCT programmes (Boswell & Baggaley, 2002).
REFERENCES
Baggaley R., Kawaye I., and Miller D., 2001, Counselling, Testing and Psychological Support. In: HIV/AIDS prevention and care in resource-constrained settings – a handbook for the design and management of programmes (P.R. Lamptey and H. Gayle, eds.). Arlington, VA: Family Health International. www.fhi.org
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Best K., 2004, Family planning and the prevention of mother-to-child transmission of HIV: a review of the literature. Arlington, VA: Family Health International. www.fhi.org
Boswell D. and Baggaley R., 2002, Voluntary counselling and testing: a reference guide – responding to the needs of young people, children, pregnant women and their partners. Arlington, VA: Family Health International.
Caldwell J.C. and Caldwell P., 2002, Is integration the answer for Africa? Int Fam Plann Persp 28(2): 108–110.
Family Health International (FHI), 2002, Models of HIV voluntary counselling and testing (VCT) service delivery. Arlington, VA: FHI. www.fhi.org
Fleishman F.K.G., Hardee K., and Arawal K., 2002, When does it make sense to consider integrating STI and HIV services with family planning services? Int Fam Plann Persp 28(2): 105–107.
Horizons Program, 2001, HIV voluntary counselling and testing among youth: results from an exploratory studying Nairobi, Kenya and Kampala and Masaka, Uganda. Washington, DC: Population Council.
IPPF/WHR, 2000, Self-assessment module on integrating STI/HIV/AIDS services into sexual and reproductive health programmes. June.
Maredia J., Bharmal R.N., Gurav R.B., and Kartikeyan S., 2004, Profile of clients in voluntary counselling and testing programme for HIV/AIDS. J Comm Health 6(2): 76–80.
NACO, Training manual for doctors. New Delhi: Government of India.
National AIDS and STD Control Programme (NASCOP), 2001, National guidelines for voluntary counselling and testing. Nairobi: Ministry of Health.
Reynolds H.W., Janowitz B., Homan R., and Johnson I, 2006, The value of contraception to perinatal HIV transmission. Sex Transm Inf 7 Feb [PubMed]. PMID Nr 16505747.
Stove J., et al., 2003, Adding family planning to PMTCT sites increases the benefits of PMTCT. Issue Brief: Population and Reproductive Health. Washington, DC: USAID, October.
Sweat M.D., et al., 2004, Cost-effectiveness of nevirapine to prevent mother-to-child HIV transmission in eight African countries. AIDS 18: 1661–1671.
UNAIDS, 1999, Counselling and voluntary HIV testing for pregnant women in high HIV prevalence countries – elements and issues. UNAIDS Best Practices Collection 99.44E. www.unaids.org UNAIDS, 2001, The impact of voluntary counselling and testing – a global review of the benefits
and challenges. UNAIDS Best Practices Collection. www.unaids.org
UNAIDS, 2000, Voluntary counselling and testing (VCT). Technical Update. UNAIDS Best Practices Collection. www.unadis.org
UNFPA, 2002, Integrating HIV voluntary counselling and testing (VCT) services within family planning settings to prevent HIV infection in women – guidelines for implementation. www.unfpa.org
WHO/UNAIDS, 2001, Technical consultation on voluntary HIV counselling and testing: models for implementation and strategies for scaling of VCT services. Harare, Zimbabwe. 3–6 July.
WHO/UNFPA, 2006, Glion consultation on strengthening the linkages between reproductive health and HIV/AIDS: family planning and HIV/AIDS in women and children. Geneva: WHO. WHO/HIV/2006.02. www.who.int
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CHAPTER 22
PREVENTION OF MOTHER-TO-CHILD TRANSMISSION
Abstract
Intrauterine transmission can occur as early as 8 weeks of gestation. Many intervention strategies have been suggested during the antenatal, intranatal, and post-natal periods. After counselling, if the client decides to continue her pregnancy, she should be informed about post-partum contraception and infant feeding options. While advising infant feeding options, the health care provider should bear in mind the health and socio-economic status of the mother, the cost of breast milk substitutes, and the risks of not breastfeeding. After delivery, the baby should be screened for HIV status and this should be preceded, and followed, by counselling of the mother or both parents. In asymptomatic babies, all the vaccines are to be given as per the national schedule. If the baby is symptomatic, all vaccines except live vaccines should be given as per the national schedule.
Key Words
Antiretroviral therapy, Breastfeeding options, Elective caesarean section, HIV in women, Infant feeding options, Intrapartum transmission, Intrauterine transmission, Medical termination of pregnancy, Mode of delivery, Mother-to-child transmission, MTCT estimation, Post-natal transmission, Transplacental transmission, Vaginal cleansing, Vitamin A, Vertical transmission
22.1 – HIV INFECTION IN WOMEN
In 1985, India joined the ranks of the first few countries that initiated serosurveillance among high-risk groups. The first group of seropositive individuals (10 female sex workers) was detected in April 1986. Within a short period of 18 months, it became apparent that heterosexual promiscuity was the major mode of transmission in India and that the seropositivity was low (about 4 per 1,000). HIV seropositive pregnant women (first detected in 1986) and their infants were followed up and HIV-infected children were detected in 1987–1988 (Ramachandran, 1990). Most HIV-infected women live in developing countries and have limited access to health care facilities. Occurrence of HIV-related diseases and eventual death of the mother devastates the family. Most HIVinfected infants also die by the age of 5 years. The uninfected infants face the frightening prospect of becoming AIDS orphans, with all its associated adverse consequences.
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22.1.1 – Estimating Seroprevalence
The WHO estimates the number of HIV-positive women from available national or regional estimates of HIV infection and the male to female ratio reported in AIDS cases or large community surveys (Chin, 1990). A two-step procedure is followed to estimate the number of HIV-positive pregnant women and infants:
1.Number of births among HIV-infected women is calculated from available data on seroprevalence age-specific fertility rates in each country.
2.Number of infected infants is calculated on the assumption that 25 per cent of infants born to HIV-infected women are infected at birth.
It is difficult to calculate mortality rates for women and children in developing countries since reliable cause and age-specific mortality rates are not available. The WHO has developed the following model for calculating the impact of the HIV epidemic on the under-5 mortality rate (U5MR) in a population with U5MR of 100 per 1,000.
(a)If 5 per cent of pregnant women are HIV-infected, the U5MR will increase by 9 per cent.
(b)If 10 per cent of pregnant women are HIV-infected, the U5MR will increase by 18 per cent.
(c)If 20 per cent of pregnant women are HIV-infected (as in sub-Saharan Africa), the U5MR will increase by 36 per cent (Chin, 1990). Thus, the HIV epidemic has wiped out the decline in maternal and child mortality achieved in the last few decades.
22.1.2 – Need for Routine Screening for HIV in Pregnancy
Many experts advocate routine screening of all pregnant women for HIV infection on the same lines as screening for syphilis. The rationale for screening for syphilis is to provide therapeutic intervention to prevent intrauterine infection. The justification for routine HIV screening is as follows:
●ARV drugs are available to prolong the asymptomatic period.
●If found seropositive, she could be advised to take steps for preventing transmission.
●It enables identification of children who may need follow-up and social support.
●Although no therapeutic intervention is available to prevent intrauterine HIV infection, the pregnant woman may be advised to undergo MTP, if found seropositive in early pregnancy.
22.1.3 – Problems with Routine Screening
Even in countries where MTP is legal, many HIV-infected women may refuse to undergo MTP. Studies have shown that most women will not change their reproductive choices even after they are informed about their HIV-positive status
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(Ahluwalia et al., 1998). In most developing countries, most HIV-infected women do not belong to any high-risk group. Screening of all pregnant women is impracticable since the vast majority of them do not attend antenatal clinics. HIV screening facilities are neither available nor affordable. Thus, most infected women would continue to remain undetected. In the developed countries, infected pregnant women usually belong to high-risk groups, know about HIV infection, and most avail of antenatal care. However, many may not consent to undergo HIV screening (Ramachandran, 1990).
22.2 – RISK FACTORS IN PREGNANCY
Almost 30–50 per cent of the neonates acquired infection during the antenatal period and about 50–70 per cent during the intrapartum period (Working Group on MTCT, 1995). The risk of mortality in HIV-positive babies is 50 per cent in first 2 years of life and 80 per cent in first 5 years (Working Group on MTCT, 1995). MTCT is also called “transplacental” or “vertical” transmission.
Biological Risk Factors: The rate of transmission from male to female is two to three times higher than that from female to male (European Study Group, 1996; Royce et al., 1997). It has been suggested that the Langerhans’ cells of the uterine cervix may provide a portal of entry for HIV and some HIV serotypes may have higher affinity for these cells, and therefore, may be more efficient in heterosexual transmission (Soto-Ramirez et al., 1996). Vulval and vaginal inflammation or ulceration may facilitate entry of the virus. Inadequately treated or silent chlamydial and other STIs may also act as cofactors for HIV infection and transmission (Hoegsberg et al., 1990; Mayaud, 1997; Sewankambo et al., 1997; Laga et al., 1993). History of genital ulceration has been established as a cofactor for HIV acquisition (Latif et al., 1989; Johnson et al., 1989; Plourde et al.; 1994). Other non-sexually transmitted lesions of the cervix such as schistosomiasis may also facilitate HIV infection (Feldmeier et al., 1994). Women in primary infection stage and those in terminal stage (AIDS) have a higher risk of transmitting the virus. History of HIV-positive babies in previous deliveries is a risk factor. Repeated pregnancies, poor nutrition, and other infections result in worsening of the already lowered physiological immunity in pregnancy, leading to rapid progression of the disease (NACO, Training Manual for Doctors).
Social Risk Factors: In developing countries, where male resistance to use of condom is common, female barrier methods are expensive or unavailable (UNAIDS/WHO, 1999; Feldblum et al., 1995; Drew et al., 1990). The desire and societal pressure to reproduce often prevent women from taking necessary precautions to guard against infection. Even after diagnosis of HIV seropositive status, most women will not change their reproductive choices (UNAIDS/ WHO, 1999).
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22.2.1 – Effect of Pregnancy on HIV Infection
In normal pregnancy, there is a decrease in levels of Ig molecules, complement, and a more significant decrease in CMI. These normal changes have led to the concern that pregnancy would accelerate the progression of disease in HIVinfected women (Minkoff, 1995; Rich et al., 1995; UNAIDS/WHO, 1999). However, studies comparing HIV-infected pregnant women with never-pregnant controls have revealed no difference in –
(a)Progression of natural history of HIV
(b)Death rate between the two groups
(c)Birth weight of babies (Markson et al., 1996; UNAIDS/WHO, 1999). Higher maternal mortality seen in some African countries appears to be due to more women with advanced disease becoming pregnant, resulting in higher rates of HIV-related complications. Pregnant HIV-infected women were more likely to develop bacterial pneumonia. Infections were more common during the postpartum period in HIV-positive women (UNAIDS/WHO, 1999).
22.3 – PROBABLE TIMINGS FOR TRANSMISSION
A substantial proportion of infection occurs late in pregnancy (“intrauterine transmission”) or at the time of delivery (“intrapartum transmission”). Knowledge about the likely timing of MTCT is important for planning feasible interventions (UNAIDS/WHO, 1999). If the virus is detectable within 48 hours of birth, the infant is determined to be infected in utero. Intrapartum infection is assumed if the viral studies are negative during the first week of life, but positive between 7 and 90 days (Bryson et al., 1992).
Intrauterine Transmission: Intrauterine transmission can occur as early as 8 weeks of gestation. HIV-1 and p24 viral antigens have been detected in foetal specimens and placental tissue. The rapid progression of infections in some infants suggests that the infection may have been acquired in utero (Viscarello et al., 1992; Backe et al., 1993; Langston et al., 1995).
Intrapartum Transmission: Data from a register of twins reveal that the first-born twin had a twofold higher risk of contracting HIV-1, as compared with the second-born twin (Goedert et al., 1991). It is believed that the vaginal delivery of the first twin reduces the exposure of the second twin to the virus in the cervical and vaginal secretions (UNAIDS/WHO, 1999). Elective caesarean section has been shown to reduce the risk of transmission (European Collaborative Study, 1994). Prolonged (more than 4 hours) rupture of membranes is shown to increase the risk of transmission (Women and Infants Transmission Study Group, 1996). It takes some days after infection for viral studies to become positive. Negative reports of viral studies in about half of the infected infants, at the time of birth indicate that the transmission occurred during labour or delivery (UNAIDS/WHO, 1999).
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Post-Natal Transmission: Post-natal transmission through breastfeeding is assumed to explain most of the differences in transmission in rates between developed countries (no or short period of breastfeeding) and developing countries (prolonged breastfeeding) (UNAIDS/WHO, 1999). Some researchers have recovered HIV in both free and cellular portions of breast milk. Infection through breastfeeding has been associated with maternal immune suppression, maternal vitamin A deficiency, and a lack of IgM and IgA in breast milk (van de Perre et al., 1992; Semba et al., 1994; Nduati et al., 1995).
22.4 – FACTORS AFFECTING MTCT
22.4.1 – Viral Factors
High levels of maternal viraemia (advanced disease, high levels of p24 antigens in blood) increase the risk of transmission (European Collaborative Study, 1992; Mayaux et al., 1997; Thea et al., 1997). The new technique of quantitative PCR for DNA and RNA has shown an increased association between maternal viral load and risk of transmission from mother to child. Local viral load in cervicovaginal secretions is also an important determinant of transmission during the intrapartum period (John & Kreiss, 1996; Loussert-Ajaka et al., 1997). Little is known about the role of mucosal HIV-1 antibodies and viral shedding in the genital tract, in intrapartum transmission (John & Kreiss, 1996; John et al., 1997). Maternal ARV therapy during pregnancy and postexposure prophylaxis in the child after birth is thought to reduce transmission by reducing the viral load (Newell et al., 1997).
22.4.2 – Maternal Factors
MTCT is more likely with low CD4 counts or high CD4/CD8 ratios in maternal blood (Minkoff, 1995; Fowler & Rogers, 1996). Unprotected sex during pregnancy has been linked to an increased risk of MTCT. This is attributed to: (a) repeated exposure to different viral strains during pregnancy, probably from multiple sexual partners (Bulterys & Goedert, 1995); (b) repeated infection with the same strain of HIV, probably from the same sexual partner; (c) effect of cervical or vaginal abrasions or inflammation; (d) increase in chorioamnionitis (Naeye & Ross, 1983); and (e) increased viral shedding in cervicovaginal secretions due to STIs (Ghys et al., 1997). Women with vitamin A levels below 1.4 micromoles per litre had a 4.4-fold increased risk of transmission (Semba et al., 1994). It has been suggested that vitamin A may have immune stimulatory properties and a role in maintaining the integrity of vaginal mucosa or placenta (UNAIDS/WHO, 1999). The possible role of micronutrients like zinc and selenium has also been implied (UNAIDS/ WHO, 1999).
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22.4.3 – Placental Factors
Placental infections, chorioamnionitis, and non-infectious conditions such as abruptio placentae have also been implicated (St Louis et al., 1993; Boyer et al., 1994). Breaks in the placenta can occur at any stage of pregnancy and may be related to transmission (Burton et al., 1996). The Hofbauer cells of the placenta and trophoblasts probably express CD4 and are thus susceptible to infection. Maternal use of tobacco and “hard” drugs may cause placental disruption and increase the risk of transmission. In malaria endemic areas, infection of placenta is common in pregnancy (UNAIDS/WHO, 1999).
22.4.4 – Obstetric Factors
Obstetric factors are important because the majority of MTCT occurs during the time of labour and delivery. The suggested mechanisms for intrapartum transmission of HIV-1 include: (a) direct contact of skin and mucous membrane of the infant with maternal cervicovaginal secretions during labour; (b) ingestion of virus from these secretions; (c) fourfold increase in HIV-1 levels in cervicovaginal secretions during pregnancy; and (d) ascending infection to the amniotic fluid (Reggy et al., 1997; Henin et al., 1993). The higher rate of infection in first-born twins may be due to their longer duration of exposure to infected secretions (Goedert et al., 1991; UNAIDS/WHO, 1999). This effect is more pronounced in vaginally delivered twins, where a twofold increase in infection is seen in firstborn twins over the second-born (Goedert et al., 1991). The duration of rupture of membrane (more than 4 hours) is an important risk factor, while the duration of labour does not appear to be a risk factor (Women and Infants Transmission Study Group, 1996; UNAIDS/WHO, 1999). Obstetric factors such as the use of foetal scalp electrodes, episiotomy, and vaginal tears have been implicated in some studies, but not in others (UNAIDS/WHO, 1999). A randomised clinical trial in Europe has confirmed that delivery by elective caesarean section had a protective effect (European Mode of Delivery Collaboration, 1999).
22.4.5 – Fetal Factors
Concordance between infant and maternal human leucocyte antigen (HLA) has been associated with higher risk of transmission (MacDonald et al., 1998). Other foetal factors include co-infection with other pathogens, foetal nutrition, and foetal immune status (Steihm, 1996).
22.4.6 – Infant Factors
Mucins, HIV antibodies, lactoferrin, and secretory leucocyte protease inhibitor (SLPI) are protective factors present in breast milk (Steihm, 1996; van de Perre et al., 1993). The risk of transmission through breast milk depends on factors
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such as stage of maternal disease, maternal vitamin A levels, patterns of breastfeeding (exclusive or mixed), and presence of breast abscesses, mastitis, nipple cracks (van de Perre et al., 1992). Decreased acidity, decreased mucus, lower IgA activity, and thin mucosa in the gastrointestinal tract of the newborn may increase susceptibility (Steihm, 1996). The immune system of the newborn may also be deficient in macrophage and T-cell immune response (Steihm, 1996).
22.5 – CHALLENGES IN DEVELOPING COUNTRIES
In developing countries, cost of counselling, HIV testing, ARV therapy, and breast milk substitutes for infant feeding is very high. The mother should take informed decision regarding the appropriate method for feeding her infant. Transmission of HIV through breast milk can be avoided by continuing ARV treatment in breastfed children. In some developing countries, low priority is still given to preventing MTCT and more attention and higher budgetary allocation is given to care of under-5 children; and prevention and treatment of acute respiratory infections and diarrhoeal diseases (Soucat & Knippenberg, 1999).
22.6 – POSSIBLE INTERVENTION STRATEGIES
Intervention strategies (proposed or under investigation) are as follows:
●Medical termination of pregnancy
●Behavioural interventions in pregnancy – lifestyle changes (avoiding tobacco and drug use), avoiding unprotected sexual intercourse and multiple sexual partners
●Therapeutic interventions – treatment of STIs, supplementation of vitamin A and other nutrients, immunotherapy (under trial), and ARV therapy
●Obstetric interventions – avoiding invasive tests, birth canal cleansing, delivery by elective caesarean section
●Modified infant feeding practices – heat treatment (Pasteurisation) of expressed breast milk, early cessation of breastfeeding (UNAIDS/WHO, 1999)
22.6.1 – Nutritional Interventions
Vitamin A deficiency has been associated with increased viral load in breast milk (Nduati et al., 1995), and higher risk of MTCT (Semba et al., 1994). Several randomised control trials of vitamin A and other micronutrients such as zinc and selenium are in progress in African countries. The advantages of supplementation would be its low cost, other potential health benefits for the mother, its practicability in most health care settings, and ability to implement without HIV testing (UNAIDS/WHO, 1999). In a randomised control trial in Tanzania, multivitamin (but not vitamin A alone) supplementation in HIVpositive pregnant women has been shown to reduce the risk of low birth weight,