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OVERVIEW: HIV DIAGNOSES IN ONTARIO IN 2011
Since the last HIV update to June 2011, we have revised the analysis of HIV diagnoses, in particular, in relation to repeat HIV-positive tests which were not previously recognized or removed. This has resulted in a slight decrease in the number of HIV diagnoses. Consequently, from 1996 to 2009, the number of HIV diagnoses decreased 1.1% and, in 2010 and 2011, about 4.7%. Despite this, we believe the decrease in HIV diagnoses of about 7% in 2011 compared to 2010 is not due to artifact.
About 950 HIV infections were newly diagnosed in Ontario from 1996 to 2001. The number subsequently increased and remained at about 1,100 cases per year from 2002 to 2008, then decreased to about 1,000 per year in the most recent three years from 2009 to 2011. The proportion of females increased from 17.4% in 1996 to a peak of 29.2% in 2006 but decreased to 20-25% in the most recent five years.
Compared to 2010, the number of HIV diagnoses (i.e. first-time positive HIV tests) in Ontario in 2011 overall decreased (7.1%, 72 fewer cases). Cases decreased 9.4% in males (78 fewer cases) but slightly increased 3.1% in females (6 more cases). With respect to exposure category, the number of HIV diagnoses among MSM decreased from 1996 to 2001 but increased thereafter; it has been relative stable at about 500 cases per year since then. The annual number of HIV diagnoses decreased in the IDU category from about 120 cases from 1996 to 1999 to about 80 cases from 2000 to 2011. The number of HIV diagnoses among persons from HIV-endemic countries increased from 1996 to a peak of 2003 and remained at about 220 per year from 2004 to 2010, except in 2006, which had the highest number of cases (350) since 1996. Over time, the annual number of HIV diagnoses increased in the low risk heterosexual category and remained relative stable in the high risk heterosexual category. The trend in males was similar to that for all cases in Ontario, but the number of HIV diagnoses decreased in the IDU category. HIV diagnoses among females in the HIV-endemic exposure category markedly increased, from about 60 cases per year in 1996-99 to a peak of 200 in 2006 and then decreased since. HIV diagnoses among females in the low risk heterosexual category increased from about 40 cases per year in 1996 to 2000 to 60 per year from 2001 to 2011. Compared to 2010, HIV diagnoses in 2011 decreased in the MSM (-8.1%, 40 fewer cases), HIV-endemic (-6.9%, 14 fewer cases), high risk heterosexual (-9.9%, 4 fewer cases) and low risk heterosexual (-14.4%, 22 fewer cases) exposure categories. It increased in the IDU (3 more cases) and transfusion (5 more cases) exposure categories. With respect to health region, the overall number of HIV diagnoses in Toronto decreased from 677 in 1996 to 536 in 1997 and remained stable from 1997 to 2001. It then increased to a peak of 740 in 2002, with a decreasing trend thereafter. The Central West and Central East, other health regions experienced an increase of HIV diagnoses over time. In Ottawa, the number of HIV diagnoses appeared an increase in the most recent five years from 2006 to 2010, but decreased in 2011. We observed no increasing or decreasing trend in the other health regions.
In 2011 compared 2010, HIV diagnoses decreased in the Eastern, other (21 versus 38 cases, a 44.4% decrease), Ottawa (97 versus 155, a 37.8% decrease), Southwest (47 versus 72, a 34.1% decrease) and Central West (77 versus 86, a 10.1% decrease) health regions and increased in the Central East, other (105 versus 89, a 17.7% increase), Northern (43 versus 39, a 9.8% increase) and Toronto (555 versus 538, a 3.2% increase) health regions. For detailed trends in HIV diagnoses in the individual health regions, please see the commentary in the individual tables (Section 4).
The number of HIV tests in Ontario increased since 2001. The positivity rate was lower during the 1996 to 2011 period. An increasing trend in HIV tests was observed in the Ottawa, Central East, other, Toronto, Central West and Southwest health regions and in the MSM, HIV-endemic and low risk heterosexual categories. The number of HIV tests carried out in Ontario increased by 2.6% in 2011 compared to 2010. The increase in HIV tests occurred in the MSM (+10.7%) and low risk heterosexual (+3.8%) exposure categories. However, we observed a decrease in the number of HIV tests in the other exposure categories: MSM-IDU (-14.4%), IDU (-7.2%), clotting factor (-45.3%), transfusion (-20.1%), HIV-endemic (-8.5%), high risk heterosexual (-5.1%) and mother-to-child transmission (-12.4%).
The overall HIV positivity rate in Ontario in 2011 was 0.22%.
Compared to 2010, the positivity rate in 2011 increased in the
MSM-IDU, IDU and transfusion exposure categories but decreased
in the MSM category Last Updated: February 09, 2012 |
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