The Most Probable Past, Present, and Future of the AIDS Pandemic JAMES (Jim) CHIN MD, MPH Clinical Professor of Epidemiology School of Public Health University of California at Berkeley

? ? ? ? Probable Routes of Initial Global Spread of HIV-1 in the 1960s and 1970s

AIDS

Who is at Risk of Acquiring or Transmitting HIV Infection?

Facilitating factors*Protective factors Other STD, especially ulcerative STD Male circumcision – lack of penile foreskin Traumatic sex, “dry” sexCondom use Acute phase of HIV infection (high viral load) Potential future factors – Microbicides, vaccines Factors that can Facilitate or Limit Epidemic Sexual HIV Transmission *Facilitating factors are not co-factors since they are not required for HIV transmission but can “facilitate” or increase the risk of transmission

The Reproductive Number (R 0 ) of HIV R 0 for HIV via sexual transmission is dependent on: (1)probability a sex partner is infected with HIV [p]; (2)probability of HIV transmission per coital act [r]; (3)number of unprotected coital acts with different sex partners [n1, n2…] R 0 = (p x r x n1) + (p x r x n2)…

Risk of Sexual HIV Transmission Based on Pattern of Sex Partner Exchange Annual number (Frequency of Exchange) Pattern of Exchange Risk of HIV Transmission Examples 1 or none (No partner exchange) Monogamous or abstinent Zero or close to zero (R 0 <1) Majority of heterosexuals and many MSM Up to dozens (Months to years) Mostly serial Low (R 0 <1) Up to 20% of adults in Western countries Up to dozens (weekly to monthly) Mostly concurrent Moderate to high (R 0 >1) 20-40% of adults in SSA countries and most MSM Up to several hundreds (Daily to weekly) Concurrent High (R 0 >1) Direct/ indirect FSW and MSM in small sex networks Up to 1000 or more (Daily) Concurrent Highest (R 0 >1) Large brothel based FSW, MSM in bathhouses

Question Why is epidemic (R 0 >1) heterosexual HIV transmission almost non-existent in most countries in the world but is so prevalent in sub-Saharan African countries and to a lesser extent in several Caribbean countries and in only a few countries in South and Southeast Asia?

HIV Prevalence by Wealth Quintiles – Kenya

Understanding HIV/AIDS Numbers Reported Official Estimated Actual HIV incidence HIV prevalence AIDS incidence

How Accurate are HIV Prevalence Estimates? Estimation of HIV prevalence is more of an art than a science. With the many uncertainties in HIV serologic data and the limitations of the data, methods, and assumptions used, estimation of HIV numbers cannot be precise. Current HIV prevalence estimates tend to be high because of insufficient data on urban/rural differentials.

HIV Prevalence Rates in Selected sub-Saharan African Countries Percent HIV positive among population age national estimates based mostly on sentinel ANC data national estimates based mostly on population based data Number overestimated in millions Total overestimation for these SSA countries about 5 million 7/25/07

HIV Prevalence Rates in Selected African, Caribbean and Asian Countries Percent HIV positive among population age national estimates based mostly on sentinel ANC data national estimates based mostly on population based data /25/ Number overestimated in millions

Percent of Global Population Infected with HIV Infected Not Infected Sub-Saharan Africa 3.0% 97.0% Rest of World 0.2% 99.8% Total Global 0.5% 99.5% The “Glorious” Myth of “Generalized” HIV Epidemics Influenza pandemics >50% <50%

Region HIV+ (%) 2001 HIV+ (%) 2006 HIV Risk Behaviors Sub-Saharan Africa6.5 [9.0]5.9Heterosexual Caribbean1.5 [2.3]1.2Heterosexual South & SE Asia0.6 [0.4]0.6 [0.35]*FSW & IDU Latin America0.5 MSM & IDU E Europe & Cent Asia0.5 [0.2]0.9 [0.4]IDU Western Countries0.4 MSM & IDU N Africa & Mid-East East Asia & Pacific [0.08]Plasma & IDU GLOBAL [<1.0] Estimated HIV Prevalence in Global Regions: * In early July, 2007 estimated HIV prevalence in India was reduced from close to 6 million (0.9%) to less than 2.5 million (0.36%).

7/04/07 Highest Estimated HIV Prevalence Countries

Estimated HIV Prevalence in 10,000 Females CountryNumberHIV Transmission Swaziland>3,000Primarily heterosexual Thailand 100Primarily FSW/Clients & IDU Russia 75Primarily IDU India 50Focal FSW and IDU USA 30Mostly MSM & IDU Mexico 20Mostly MSM & IDU Malaysia 15Primarily IDU China 3IDU and paid plasma donors Philippines 1No epidemic HIV spread Turkey <1No epidemic HIV spread

Population Number HIV Prevalence Number rate (%) HIV Incidence Number rate (%) MSM720,000 85,00012%5,0000.7% IDU220,0009, %1,0000.5% MSM/IDU80,0008,00010% % Heterosexual* Males Females 5,700,000 6,300,000 2,500 5, % 0.08% % % Totals13,020,000110, %6, % Estimated HIV Prevalence and Incidence – California * Population age Estimates developed by a consensus meeting of about 50 California HIV/AIDS experts in 2001

HIV Epidemics in IDU Populations in Asia

Group Number Number HIV+ Percent HIV+ Truck Drivers FSW denying drug use* FSW admitting drug use** Total FSW * In a prior study, HIV prevalence in underground FSW not using drugs was 2.2%. ** HIV prevalence in IDU tested in detention camps in 2000 was about 25%. HIV Prevalence In Female Sex Workers and Truck Drivers in Yunnan, China,

/ Uganda Kenya Botswana

UNAIDS Report to UNGASS – May 30, 2006 OVERVIEW OF THE GLOBAL A I D S EPIDEMIC “Overall globally, the HIV incidence rate (the annual number of new HIV infections as a proportion of previously uninfected persons) is believed to have peaked in the late 1990s and to have stabilized subsequently… …Changes in incidence along with rising AIDS mortality have caused global HIV prevalence (the proportion of people living with HIV) to level off….”

Region*HIV Incidence *AIDS Death HIV:Death Ratio** Sub-Saharan Africa :1 N Africa & Middle East :1 South & SE Asia :1 East Asia :1 Latin Amer & Caribbean :1 Totals :1 UNAIDS 2006 Estimates of Annual HIV Incidence and Annual AIDS Deaths in Selected Regions *Numbers are in millions **When HIV incidence peaks, the ratio of new HIV infections to AIDS deaths is about 2:1; after 5 years it is 1.5:1; and after 10 years close to 1:1

UN Millennium target “Have halted by 2015 and begun to reverse the spread of HIV/AIDS”

1. Increase of responsible sexual behaviors, i.e., sexual Abstinence and/or Being faithful 2. Increase of consistent Condom use for risky sex behaviors 3. Saturation of infection in those with the highest sexual risk behaviors All of the above, but perhaps saturation of infection may be the most important factor! What are the Major Factors Responsible for Peaking of Sexual HIV Epidemics?

Peak annual HIV incidence numbers Peak annual numbers of AIDS deaths Modeling HIV/AIDS in Cambodia “Riding to glory on the down slope of the epidemic curve!” Start of national 100% condom program

Estimated Annual TB Cases

HIV/AIDS # % HIV/AIDS # 8 – 2% Data source: Version 3 revisions of the Global Burden of Disease (GBD) study. Top Two Leading Causes of Death in Global “Regions”

The Impact of AIDS on the San Francisco Gay Men’s Chorus

Can You Believe This? Source: WHO’s World Health Report 2004

Estimated and Projected Annual HIV Incidence in sub-Saharan Africa UNAIDS modeled baseline scenario Jim Chin’s more logical scenario UNAIDS’ comprehensive prevention & treatment scenario

Estimation and Projection of HIV Prevalence to 2020 ALL OTHER REGIONS Overestimates and projections by UNAIDS & UN Population Division SOUTH & SE ASIA Most likely scenario SUB-SAHARAN AFRICA

James (Jim) Chin, MD, MPH Clinical Professor of Epidemiology, School of Public Health University of California, Berkeley Formerly, Chief of the Surveillance, Forecasting, and Impact Assessment (SFI) unit of the Global Programme on AIDS (GPA), World Health Organization (WHO), Geneva, Switzerland Forward by Jeffery Koplan, MD, MPH Vice President, Academic Health Affairs, Emory University, Atlanta Formerly Director, Centers for Disease Control and Prevention (CDC) **** The AIDS Pandemic argues that the story of HIV/AIDS has been distorted by UNAIDS and AIDS activists in order to support the myth of the high potential risk of HIV epidemics spreading into the general population. Radcliffe-Oxford,