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Surveillance Report to December 31, 2002April 2003Division of HIV/AIDS Epidemiology and Surveillance HIV and AIDS in Canada - Surveillance Report to December 31, 2002 ISSN 1488-1926 - (On-line) ISSN 1701-4166 Information to the readers of HIV and AIDS in CanadaThe Divisions of HIV/AIDS Epidemiology and Surveillance, and Retrovirus Surveillance at the Centre for Infectious Disease Prevention and Control (CIDPC), Health Canada, are pleased to provide you with the HIV and AIDS in Canada: Surveillance Report to December 31, 2002. The Division of HIV/AIDS Epidemiology and Surveillance is responsible for all data analyses, writing and coordination of the publication of this report. This Division works in close collaboration with the Division of Retrovirus Surveillance, which manages the collection of HIV and AIDS surveillance data. A trend that will be important to monitor in the coming months is the increase observed in the number of positive HIV tests reported to CIDPC in the year 2001 and 2002. There has been a 17% increase in the number of positive HIV tests reported since 2000. This increase could be due to a combination of factors, such as increased reporting, increased testing, and/or an increased rate of new infections. There is evidence to indicate that increased testing accounts for at least part of the increase in positive HIV test reports. For example, in January 2002, Citizenship and Immigration Canada implemented a new HIV testing policy for immigrants and refugees that affected HIV test reporting in Canada. More information on the policy can be found in Section I: HIV in Canada. Of note in this report is that the number of positive HIV tests reported prior to 1995 has been affected by a data cleaning process that was undertaken in June 2002 in the province of Saskatchewan. Details of the cleaning process and reasons for case exclusion can be found in Section I, HIV in Canada. In addition, it is important to consider that, for this report, Quebec AIDS data were available only to June 30, 2002, and not to December 31, 2002. More detailed information can be found in Section III, AIDS in Canada. Please note that the number of positive HIV test reports for the province of Quebec is based on the minimum number of HIV positive individuals. Please refer to the Limitations outlined in our Technical Notes section for further explanation. Since our mid-year report, additional changes have been made to the report to make it more understandable and easier to use. A notable improvement is the method by which HIV data are imported and managed. This has resulted in identification of new information and corresponding updates to the data set. Changes more evident to the reader include i) a reduction in the number of positive HIV test reports with unknown gender; ii) new rows added to HIV tables to ensure that all unknown age cases are captured; and iii) more specific information on reports between 1985 and 1997 attributed to transmission by blood and blood products as well as heterosexual contact. This report also includes iv) newly formatted tables and an additional table indicating ethnic status in Section II, Report of the Canadian Perinatal HIV Surveillance Program; v) a newly formatted ethnic status table in Section III, AIDS in Canada; and vi) three new tables indicating exposure category in Section IV, Mortality Due to HIV/AIDS in Canada. We have also ensured that sections in the report are consistent from year to year to help guide the reader to the tables of interest and have incorporated feedback on the report received at our recent National HIV/AIDS/STI Surveillance Meeting held in March of this year. A resource that may be of assistance in the interpretation of this report is entitled, “A Guide to HIV/AIDS Epidemiological and Surveillance Terms”. Epi Updates, which summarize the current status of HIV and AIDS in Canada, are also available, through the Division of HIV/AIDS Epidemiology and Surveillance, on the Web site for Division publications or through the HIV/AIDS Clearinghouse. An address is listed for each on the inside cover of this report. We are continuing to make improvements to this report and always welcome and appreciate your comments and suggestions. Yours sincerely,
Table of Contents
At a GlanceIntroduction This surveillance report presents HIV and AIDS surveillance data to December 31, 2002, reported to the Centre for Infectious Disease Prevention and Control (CIDPC) from Canadian provinces and territories. This section presents highlights of the main findings in the data through text and figures and is followed by detailed tables with the underlying data. HIV and AIDS surveillance data, as presented in this report, represent only those individuals who seek testing and/or medical care. The number of positive HIV test reports provides a description of those who came forward for testing, whose condition was diagnosed and who were reported HIV positive. It does not, however, represent the total number of individuals living with HIV (prevalence) or newly infected each year (incidence). Similarly, the number of reported AIDS cases represents those who sought medical care, were given a diagnosis of AIDS and were reported to CIDPC. The number of reported AIDS cases, therefore, does not represent true AIDS incidence. HIV Surveillance Data There have been 52,640 positive HIV tests reported to CIDPC since HIV testing began in Canada in November 1985. There was an almost 30% decrease in the number of positive HIV tests reported annually over a 5-year period, from 2,985 in 1995 to 2,120 in 2000. However, in 2001, there was an increase in this number to 2,182 positive tests reported, which rose again to 2,473 in 2002. Thus, since the low in 2000, there has been a 17% increase in the number of positive HIV tests reported to CIDPC (Table 1). Although the majority of positive HIV test reports among adults continue to be attributed to males, the proportion attributed to females each year has risen. Since 1985, females have accounted for 14.3% of cumulative positive HIV test reports among adults with known gender. This proportion has increased annually since the reporting of HIV positive test reports began. Females constituted 11.4% of reports among adults in the period between 1985 and 1996, 24.3% in 1999 and 25.4% of reports in 2002 (Tables 3B and 3C). The proportion of male adult reports attributed to men aged 30-39 years has been steadily declining since 1997, decreasing from 45.5% in that year to 39.7% in 2002. However, the proportion of male adult reports attributed to men 40-49 years and 50 years and older has been on the rise. Between 1985 and 1996, the proportions were 18.1% and 6.8% respectively and were reported at 29.9% and 12.9% by the end of 2002 (Table 3B, Figure 1). Proportions attributed to young men (aged 15-29 years) have remained relatively unchanged since 1997. In 2002, the proportion attributed to this group was 17.5%. The proportion of female adult reports attributed to young women (aged 15-29 years), however, was 32.1% in 2002. Also of note is that, like reports among adult males, the proportion of reports among adult females aged 40-49 years is on the rise. The proportion has increased to 20.1% in 2002 from 11.3% reported between 1985 and 1996. As shown in Figure 2, the proportion of adult positive HIV test reports attributed to injecting drug use has continued its gradual decline into 2002, down to 23.6% from a high of 33.7% in 1997. The proportion in the heterosexual exposure category1 increased steadily from 9.1% in 1985-1996 to a high of 32.6% in 2001, but has decreased slightly to 29.9% in 2002. After a decrease in 2001 to 36.1% of adult positive HIV test reports, the proportion attributed to men who have had sex with men (MSM) increased to 41.5% in 2002 (Table 4A, Figure 2).
1 Note: Heterosexual exposure category includes three subcategories: sexual contact with a person at risk, origin from a pattern II country and sex with the opposite gender as the only identified risk (NIR-HET) FIGURE 1Proportion of male adult (>= 15 years) positive HIV test reports by age group and year of test FIGURE 2 Perinatal HIV Surveillance Data The Canadian Perinatal HIV Surveillance Program has identified 1,590 infants, born between 1980 and 2002, perinatally exposed to HIV in Canada (Table 7). The number of HIV-exposed infants reported per birth-year to the program has increased steadily from 54 infants in 1990 to 158 in 2002. The overall proportion of HIV-exposed infants whose mothers' HIV status was attributed to the exposure category of sexual contact was 68.8%, and 29.2% were attributed to injecting drug use. Although the number of HIV-exposed infants reported to the Canadian Perinatal HIV Surveillance Program has increased for each birth-year, the proportion of infants confirmed to be HIV infected has decreased, from 50% (27/54) in 1991 to 2% (3/148) in 2002 (Table 8). Correspondingly, the proportion of HIV positive mothers receiving antiretroviral therapy (ART) prophylaxis has increased steadily, reaching a high in 2002 of 89.9% (133/148) of mothers and infants reported to the program. Table 10 identifies all infants born to HIV infected mothers followed by the Canadian Perinatal Surveillance Program. Since 1984, 44.1% of these infants have been born to women from the Black community, whereas 36.5% were born to White women and 14.6% to Aboriginal women. Cumulatively, of all infants whose status has been confirmed (i.e. confirmed infected or confirmed not infected), 34.7%, 22.6% and 16.5% were confirmed to be HIV positive in Black, White and Aboriginal populations respectively. However, for HIV-exposed infants born in 2002 whose infection status has been confirmed, 6.7%, 0.0% and 0.0% were HIV positive in these communities respectively. It is important to note that a number of infants born in 2002 have yet to have their HIV infection status confirmed. AIDS Surveillance Data Since the beginning of the epidemic in the early 1980s, there have been 18,469 AIDS cases reported to CIDPC (Table 11). As there is often a substantial delay between the time at which a person receives adiagnosis of AIDS and the time at which CIDPC receives a report of that diagnosis, adjustments to the number of reported AIDS cases are calculated. After adjusting for reporting delay, it is estimated that there will be 19,123 AIDS cases reported to CIDPC to the end of 2002 (Figure 3). The number of AIDS cases adjusted for reporting delay accounts only for delays in case reporting, not for underreporting (or non-reporting) of AIDS cases. The continued steep decline in reported AIDS cases in recent years may be an overestimate of the rate of decline in diagnosed AIDS cases, as it may in part reflect increased underreporting of AIDS cases; this is supported by anecdotal evidence. Of the actual number of AIDS cases reported to CIDPC up to December 31, 2002, females account for 8.1% of cumulative cases for which age and gender were reported. Among reported adult AIDS cases, the proportion of females increased from 5.8% during the period 1979-1992 to 15.0% in 2001. The proportion has since increased to 18.2% in 2002 (Table 13). When adult AIDS cases are examined by age group, the greatest proportions are attributed to those aged 30-39 years and 40-49 years respectively. For those aged 30-39 years, the proportion decreased steadily from a high of 47.4% in 1994 to a low of 38.7 % in 2000, but rose slightly to 39.2% in 2002. There has been a corresponding increase in the proportion attributed to those aged 40-49 years, from 25.8% before 1993 to 32.2% in 2002. When considering these changing proportions, it is important to note that the number of reported AIDS cases has declined substantially since the beginning of the epidemic (Tables 14B and 14C). The proportion of reported adult AIDS cases among MSM has steadily declined over the last decade (Figure 4). Before 1993, the proportion attributed to this exposure category was 78.9%, and this declined to 45.6% in 1999. There was an increase to 50.2% in2000, but the proportion has since declined to 39.2% in 2002, the lowest since the beginning of the epidemic. The proportion of reported adult AIDS cases attributed to the heterosexual exposure category has steadily increased from 9.9% between 1979 and 1992 to a high of 35.3% in 2002. There had been a steady rise in the proportion of IDU, from 2.7% in the period between 1979 and 1993 to 21.3% in 1998. However, since that time there has been a leveling off, and IDU represented 22.2% of reported AIDS cases among adults in 2002 (Table 15A). As outlined in Figure 5, the proportion of reported AIDS cases among Whites has decreased from 87.5% before 1993 to 57.0% in 2002. The proportion of reported AIDS cases among members of the Black community increased from 7.9% prior to 1993 to 15.0% in 1999, then dropped to 10.2% in 2000, rising again to 16.9% in 2002. The proportion of reported AIDS cases in Aboriginal groups increased from 1.3% between 1979 and 1992 to 10.1% in 1999, decreased to 5.6% in 2001, and then rose again to 14.8% for the current reporting period. Note, however, that samples are small and Quebec is represented by only half-year AIDS data. FIGURE 3 FIGURE 4 FIGURE 5 Note: There are different vertical scales for white and non-white ethnic categories. HIV/AIDS Mortality Data The first reported death due to HIV/AIDS was the death of a reported AIDS case in 1980. The number of such deaths increased from the beginning of record keeping to 1995, when the number of deaths reported was 1,481. There has, however, been a dramatic decrease in reported deaths among reported AIDS cases since that time (Table 19). There has been an increase over time in the proportion of females among recorded deaths, consistent with the rising proportion over time of females among HIV/AIDS cases (Table 22). In Canada, there are two sources of national information on the number of deaths due to HIV/AIDS: CIDPC, which publishes data on reported deaths among reported AIDS cases, and the Health Statistics Division of Statistics Canada, which collects data on all deaths, including those attributed to HIV infection. Please see Section IV for more details on the respective advantages and limitations of these two sources. Interpretation The increase in the number of positive HIV test reports during 2001 and 2002 is worth noting. As can be seen from Table 5B, this increase is primarily seen in data from Ontario and Quebec. At present, the reasons for such an increase are not clear: whether increased reporting, increased testing and/or increased HIV infection rates. However, at least part of the increase can be attributed to Citizenship and Immigration Canada's new policy on HIV testing for immigrants and refugees, as outlined in Section I. A number of other jurisdictions have observed similar recent increases in positive HIV test reports and are working to understand the reasons for the increase. These include the 25 states in the USA that report HIV diagnoses to the Centers for Disease Control and Prevention (CDC) as well as several states in Australia. CIDPC is collaborating with our provincial/territorial surveillance partners to further examine the possible explanations for the increase in Canada and, in a parallel process, is also working to update the national estimates of HIV prevalence and incidence for 2002.
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