AIDS – New Zealand
Issue 39 – November 1998
ISSN 1170-2656
AIDS and HIV infection in New Zealand to end of September 1998
In the third quarter of 1998, there were 4 notifications of AIDS (2 males and 2 females), while 35 people (29 males, 6 females) were found to be infected with HIV. To the end of September 1998, in total 660 people (628 male and 32 female) have been notified with AIDS, and 1317 people (1157 male, 141 female and 19 sex not stated) have been found to be infected with HIV. The cumulative incidence rate of AIDS notifications to the end of September 1998 was 19.1 per 100,000 total population.
Heterosexual transmission of HIV among people diagnosed in New Zealand
In New Zealand male homosexual contact has been the predominant mode of transmission among people found to be infected with HIV and with AIDS. However a greater number of those diagnosed with HIV in recent years have
been infected through heterosexual contact. Extra information, including country of infection and ethnicity, has been sought on all people diagnosed with HIV in New Zealand since 1996. These data allow comparison of people infected through heterosexual and homosexual contact and provide insights into the reasons for the rise in the number of heterosexually infected people.
Since the start of 1996, 241 people have been found to be infected with HIV in New Zealand. Among the 208 for whom a likely means of infection has been reported, 101 (49%) were men infected through sex with men, and 91 (44%) - 51 men and 40 women – were infected through heterosexual contact.
Table 1 Place of infection of people diagnosed with HIV in New Zealand since start of 1996 who were infected through homosexual and heterosexual contact
Transmission category and country of infection
The pattern of place of infection varies between those infected through homosexual and heterosexual contact (Table
1). Over two thirds of infections through male homosexual contact in this period were reported to have occurred in New Zealand. In contrast, among those heterosexually infected, only 8% of men and 25% of women were infected in this country.
Of the heterosexual infections, nearly 70% were reported to have occurred in African or Asian countries (Table 2). Thailand was the site where most of the Asian acquired infections occurred.
Table 2 Reported country of heterosexual infection
Heterosexual transmission of HIV within New Zealand
Fourteen people, 4 men and 10 women were reported to have been heterosexually infected in New Zealand. 'First-generation transmission' describes heterosexual spread from a partner at high risk of HIV. Male partners of women considered at high risk are bisexual men, men from high prevalence areas, injecting drug users, and
blood product recipients. The risks are the same for female partners of men although bisexual women are not regarded as high risk. 'Second-generation transmission' is infection from a partner who had previously been infected through first-generation transmission.
Some information can be gained on the pattern of heterosexual transmission within New Zealand from the data on diagnosed HIV infections. However the data are limited as not all at risk will have been tested, and information is unavailable on some people.
Among the 14 people reported to have been heterosexually infected in New Zealand, there is information on the partner's risk for 9, 3 men and 6 women. Of the men, 2 were infected through first-generation, and one through second-generation transmission. All of the 6 women whose partner's risk was known were infected through first-generation transmission.
These data suggest that whilst heterosexual transmission away from the high risk groups has occurred in New Zealand, it has not been widespread.
Transmission category and ethnic group
As with place of infection, different patterns are seen for the ethnicity of people infected through homosexual and heterosexual contact (Table 3). For men infected through homosexual contact the ethnic distribution is similar to that of the New Zealand population for the age group most affected. However for those infected through heterosexual contact, those classified as 'Other' are greatly overrepresented. Combining the information on ethnicity and place of infection shows that of the 14 people who were reported to have been heterosexually infected in New Zealand, 9
were European, 2 were Maori, one was a Pacific island person and there were 2 in the ‘Other’ category. Of the 63 people heterosexually infected in African and Asian countries, 7 were reported to be European.
Table 3 Ethnicity of people reported infected through homosexual and heterosexual contact in New Zealand since start of 1996
* All male
† Includes people who belong to Maori and another ethnic group
Notifications of AIDS in New Zealand in the third quarter of 1998
Four people were notified with AIDS in the third quarter of 1998. This is the smallest number of notifications of AIDS in one quarter received since the AIDS Epidemiology Group began monitoring the epidemic. A major reason for this fall is likely to be the use of treatments which are effective in slowing the progression of HIV in infected people.
Of the 2 males notified, one was a man reported to have had sex with men. The other man, who was not previously known to be infected with HIV, was admitted to hospital severely ill and died soon after. How he was infected was not determined.
Of the 2 females notified, one was a woman reported to have been heterosexually infected. She was a sex worker from a high prevalence area. The other female was a 3 year old child from overseas who was believed to have been
perinatally infected.
People found to be infected with HIV in New Zealand in the third quarter of 1998
In the third quarter of 1998, 35 people were found to be infected with HIV. Of these 29 were male, and 6 were female. This is a relatively large number of people to be diagnosed in one quarter, and is due to the large number of new immigrants found to be infected. Of the 29 males found to be infected, information has been obtained on 22. Of these 22, 8 were reported to have had sex with men, 13 were reported to have been heterosexually infected, and for one person the means of infection was not known. Of the 13heterosexually infected men, 12 were from high prevalence areas, and the remaining man was reported to have been infected in such an area.
Of the 6 females found to be infected, information has been obtained on 4. All 4 were reported to have been heterosexually infected, and to be from high prevalence areas. One of these women was infected in New Zealand.
In total there have been 1317 people, 1157 males, 141 females and 19 people whose sex was not stated, found to be infected in New Zealand to the end of September 1998. Information on the categories of risk, and ethnicity, of the 660 people notified as having AIDS and found to be infected with HIV in New Zealand to the end of September 1998 is
shown in Tables 4 and 5.
Table 4 Exposure category by time of notification of people with AIDS, and by time of diagnosis for those found to be infected with HIV
NS = Not stated
* Includes people who have developed AIDS
Table 5 Ethnicity by time of notification of people with AIDS, and by time of diagnosis for those found to be infected with HIV. Information on ethnicity of people found to be infected with HIV is only available since 1996
For further information about the occurrence of AIDS in New Zealand contact:
Dr Nigel Dickson
AIDS Epidemiology Group
Department of Preventive and Social Medicine
University of Otago Medical School
PO Box 913
Dunedin
New Zealand
Tel: (03) 479 7211
Fax: (03) 479 7298
Email: ndickson@gandalf.otago.ac.nz
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Related information:
AIDS/HIV page www.moh.govt.nz/aids |