Antenatal HIV antibody testing in Australia

Review of antenatal testing policies and practice for HIV and hepatitis C infection

OBJECTIVE

To investigate antenatal HIV and HCV testing policy and practice in Australia.

METHODS

A survey of private obstetricians and general practitioners (GPs) affiliated with the Royal Australian and New Zealand College of Obstetricians and Gynaecologists and directors of obstetric units in public hospitals was undertaken. Surveys were mailed to 40% and 20% random samples of private obstetricians and GPs, respectively, and all public hospital obstetric units. The questionnaires included information on type of antenatal policy, proportion of women tested for HIV and HCV, and number of HIV and HCV-positive women receiving antenatal care.

RESULTS

Of the 995 surveys distributed, 847 (85%) were returned. Of these 847, 277 (33%) were returned from practitioners or hospitals no longer involved in antenatal care. The response rates from the remaining practitioners (n=570) included 87% from private obstetricians, 78% from GPs, and 71% from public hospitals. The proportion of private obstetricians, GPs and public hospitals with an antenatal testing policy for HIV was 62%, 42% and 44%, and for HCV 65%, 41% and 39%, respectively. Universal offer of antenatal testing among private obstetricians, GPs and public hospitals was 47%, 62% and 23% for HIV and 54%, 46% and 23% for HCV, respectively. During 1999, an estimated 33% of pregnant women were tested for HIV and 37% for HCV. Based on reported numbers of women in antenatal care, prevalence rates were estimated at 0.23 per 1,000 and 13 per 1,000, for HIV and HCV, respectively.

CONCLUSIONS

Antenatal testing policy and practice varies widely in Australia. The lack of uniformity may reflect differing policies among clinical and public health bodies.

Reconsidering HIV testing--consent is still the key

The high quality and easy accessibility of HIV testing in Australia has been one of the reasons for Australia's effective response to the epidemic. However there have been a number of changes in the epidemiology of HIV and new technologies and treatments have emerged since the last Australian HIV policy was released in 1998. Antenatal testing to prevent vertical transmission, the licensing of rapid, point-of-care test kits in the United States and the problem of late diagnosis of infection in some populations are important issues to consider in the context of the drafting of a new HIV testing policy. The terms 'pre- and post-test counselling' are seen, by some, as barriers to HIV testing in the broader community. Reframing the process with a focus on the desired result (i.e. informed consent for voluntary testing) rather than on the process (i.e. pre-test counselling) could be one way to increase the rate of appropriate testing.

Uptake of HIV screening in an antenatal clinic

OBJECTIVE

To assess the uptake of HIV screening in pregnant women attending a tertiary hospital antenatal clinic.

METHODS

An audit was undertaken in an antenatal clinic where HIV screening was routinely offered to all women following counselling. For the women offered HIV testing, note was taken whether the woman agreed to testing or refused, and if so, the reason for refusal.

RESULTS

Sixty eight percent of women who were offered testing opted to have the test performed. Thirty two percent of women decided against testing, with half of these reporting a recent (negative) HIV test result.

CONCLUSIONS

Over 80% of pregnant women were willing to have HIV testing.

IMPLICATIONS

With the introduction of recommendations that all pregnant women be given the opportunity for HIV screening, a high participation rate can be expected from women who are offered testing, with the potential for minimisation of vertical transmission by identification of HIV positive women.

Use of interventions for reducing mother-to-child transmission of HIV in Australia

OBJECTIVE

To describe the extent and outcome of use of interventions for reducing the risk of HIV transmission from mother to child in Australia.

DESIGN

National surveillance for perinatal exposure to HIV.

PARTICIPANTS AND SETTING

Notified cases of HIV infection in women in Australia and their perinatally exposed children, 1982-1999.

OUTCOME MEASURES

Trends over time in use of interventions (antiretroviral therapy in pregnancy, elective caesarean delivery and avoidance of breastfeeding) and perinatally acquired HIV infection.

RESULTS

By 31 March 2000, 204 children were reported as having been born in 1982-1999 to 162 women whose HIV infection had been diagnosed by 31 December 1999. The child's HIV infection status was established for 182 (89.2%); the mother's HIV infection was diagnosed antenatally in 91 of these cases (50%). Among women diagnosed antenatally, use of elective caesarean delivery and antiretroviral therapy in pregnancy increased significantly, from 3% and 14% by women whose children were born in 1982-1993, to 21% (P=0.01) and 88% (P<0.001), respectively, by women whose children were born in 1994-1999. Most women (95%) diagnosed antenatally avoided breastfeeding their children. The percentage of infected children born to women diagnosed antenatally declined from 26% among children born in 1982-1993 to 19% among those born in 1994-1999. The percentage of infected children was significantly lower among those whose mothers used antiretroviral therapy in pregnancy (11% versus 36%; P=0.03).

CONCLUSION

Antiretroviral use in pregnancy, elective caesarean delivery and avoidance of breastfeeding have been effective interventions for reducing the risk of mother-to-child HIV transmission in Australia. While the rate of perinatal HIV transmission has declined, it remains high in comparison with rates reported from other industrialised countries.

Paediatric HIV update

Less than half of the paediatric HIV infections recorded in Australia have resulted from perinatal transmission, but in recent years this has been the predominant mode of infection. There are 136 infants who are known to have been exposed perinatally to HIV in Australia: 49 of these are infected. Caesarean section is thought now not to reduce the risk of perinatal transmission (PNT); rather, the risk increases with duration of membrane rupture and rises rapidly after 4 h of membrane rupture. However, no data exist to show that interventions to expediate delivery after membrane rupture reduce the risk of PNT. Data such as these suggest that the majority of perinatal infections (probably about 60%) occur close to the time of delivery. While the overall risk of PNT for non-breast fed infants is approximately 20-25%, the risk of infection for the infant is considerably increased when there is evidence of increased maternal viral burden. Advanced maternal disease predicts that if the infant is infected there is more likely to be early progression of HIV than is the case for the less frequently infected infants of mothers who are asymptomatic. Bottle feeding may prevent infection of 10% of children exposed perinatally. Use of zidovudine by the mother in the third trimester and i.v. zidovudine during labour, followed by oral zidovudine for the infant for 6 weeks can reduce the PNT rate by two thirds, to about 8%. Approximately 3% of uninfected infants with perinatal HIV exposure may be found to be transiently virus positive but eventually become antibody negative and thus appear to have eliminated the virus. The risk of Pneumocystis carinii pneumonitis (PCP) cannot be predicted on the basis of CD4 count and it is recommended that all children of infected mothers commence PCP prophylaxis around the age of 6 weeks-2 months and continue that therapy until the age of 12 months or until it becomes clear that the infant is uninfected. The cumulative risk of AIDS increases rapidly during the first year of life to about 20%, then more slowly at a rate of about 2 or 3% a year. The shape of this curve reveals the bimodal progression of HIV disease in children. About 15-20% of children rapidly develop a severe immune deficiency, opportunistic infections and, in most cases, encephalopathy. There is a very high morbidity rate in this group of children, most of whom die before the age of 3 or 4 years. In contrast, 80-85% of children only become immunodeficient after a relatively long period, which is similar to or perhaps even longer than that in adults. Recent studies indicate that zidovudine antiviral monotherapy is no longer appropriate. While no clear alternative to monotherapy has emerged most would, wherever possible, commence antiretroviral therapy with a combination of two or three drugs including zidovudine plus didanosine or lamivudine. If a third drug is used it would probably be a protease inhibitor.

HIV & breastfeeding: a model for sensitive midwifery

The following article forms part of an overall submission which assisted the author in winning the 1996 Victorian Irving Buzzard Prize. It explores important present day issues of HIV and Breastfeeding and provides an overview of a developed Model designed to help the Midwife sensitively and informatively assist the HIV positive mother in all facets of her decision making regarding infant feeding, and many other associated issues.

Perinatal exposure to HIV in Australia, 1982-1994

OBJECTIVE

To describe the pattern of perinatal exposure to HIV in Australia from 1 January 1982 to 31 December 1994.

DESIGN

National surveillance for perinatal exposure to HIV.

PARTICIPANTS AND SETTING

Women with diagnosed HIV infection in Australia whose children were exposed to HIV perinatally.

OUTCOME MEASURES

Number of reported cases of women with diagnosed HIV infection who have had perinatally HIV-exposed children.

RESULTS

By 31 December 1994, 91 women diagnosed with HIV infection had had 111 perinatally exposed children. While the rate of perinatal exposure to HIV was highest in the Australian Capital Territory and New South Wales, the rate was substantially lower than the rate of diagnoses of HIV and AIDS in women of child-bearing age. Before 1989, only 15% (6/39) of women knew of their HIV infection before the birth of their first perinatally exposed child: by 1989-1994, this had increased to 64% (32/52; P < 0.0005). Overall, exposure to HIV was attributed to heterosexual contact only, injecting drug use or receipt of blood or tissue by 48%, 31% and 18% of women, respectively. Source of HIV exposure changed from a history of receipt of blood in 78% of women whose first exposed child was born in 1982-1985 to heterosexual contact only in 61% of women whose first exposed child was born in 1992-1994. 38 children acquired HIV infection perinatally. The HIV transmission rate to children born to women diagnosed with HIV infection before delivery was 21.6% (11/51).

CONCLUSIONS

Perinatal exposure to HIV in Australia remains rare. While the proportion of women diagnosed with HIV infection after delivery decreased, a substantial number continued to be diagnosed after delivery, precluding use of current interventions that can reduce the risk of perinatal transmission. It may be appropriate to review the application of HIV testing during pregnancy in Australia.

A profile of HIV testing in Victoria to the end of 1993. Victorian Collaborative Group on HIV and AIDS Surveillance (VCGHAS)

Examination of testing patterns for human immunodeficiency virus (HIV) in a population is important because it affects interpretation of surveillance data on new HIV diagnoses and can guide the targeting and evaluation of campaigns to encourage appropriate antibody testing. This report describes a relatively inexpensive mechanism of collecting information on who is being tested for HIV in Victoria (other than at the Blood Bank). The annual number of HIV tests performed in Victoria increased steadily throughout the 1980s but the rate of increase slowed in the early 1990s. By 1993, women accounted for almost half of HIV tests, although they made up only 8 per cent of positive tests. There were marked differences in the volume of testing and testing profiles of different laboratories. The information available on personal risk category and the reasons for HIV tests show that many people of low risk are tested, although conclusions are limited by inadequate information elicited or provided by many requesting doctors. For better information on what is occurring with respect to HIV testing, the fundamental requirement is better compliance from requesting doctors in supplying basic information on who they test and why.