Large study spotlights limits of HIV treatment as prevention

first_img Click to view the privacy policy. Required fields are indicated by an asterisk (*) As François Dabis from ANRS explained, less than one-third of the people who were eligible for treatment in both groups visited a clinic within 3 months, and less than half had at 1 year. Another 9% of the eligible people in the immediate treatment arm who went to the clinic opted not to start ARVs, meaning only 43% went on treatment in the communities that researchers had hoped would have every infected person taking the drugs. The 22 communities all had roughly the same rate of new HIV infections, about 2% per year. “Linkage to care was far from optimal and when it did occur, it occurred slowly,”  Dabis said.One possible reason the trial failed to see a difference between the groups is that too many people in the immediate treatment arm did not take ARVs. In effect, these untreated people transmitted the virus so frequently that it overwhelmed any prevention effect from those on the drugs. It could also be that a key assumption in the trial design did not hold true. Previous studies suggested that people in the study area primarily had sex with people who lived within a few kilometers of their homes, meaning that communities in effect were closed sexual networks. This is why researchers expected that massively treating HIV-infected people in a community would have a discernible “population effect” on that group. But it could be that the assumption was wrong, and that sexual networks were far more intermingled between different communities. “Things may have changed,” Dabis said. “This is one of the precise missing links we need to explore.”The TasP results were “one of the most important” presentations at the weeklong meeting, says Myron Cohen of the University of North Carolina, Chapel Hill, who led a landmark study that showed treating HIV-infected people in long-term relationships all but eliminated the risk of transmission to their partners. “We really have immutable evidence that drugs when given in a reasonable way have the power to prevent onward transmission,” he says. “We went from this observation to hopes that scaling up that finding would allow us treat our way out of the epidemic.”Cohen says the TasP study was a carefully done, randomly controlled trial and shows that the real world has lots of complicated variables—like people learning their status and, for whatever reasons, not taking advantage of treatment. The study yielded an important insight, he says, because TasP “sets a bar”: Leaving aside the question of ending AIDS, treating 43% of the people in a community likely won’t have any impact on new infection rates. “We need to do a lot better than they did,” Cohen says. Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe One of the great unknowns in HIV/AIDS research is how much prevention bang you get for your treatment buck. Yes, antiretroviral (ARV) drugs make individuals less infectious, but how many people have to be on treatment to slow spread in a community and even bring epidemics to an end? A giant new study in South Africa failed to show any reduction in HIV transmission in communities even when nearly 50% of infected people received the drugs.When HIV-infected people take ARV drugs, it can stop viral growth so effectively that levels in the blood drop below detectable on standard tests. Several studies have shown that HIV-infected people on treatment who have fully suppressed the virus rarely transmit it to their sexual partners. In theory, as more infected people in a community start treatment, new infection rates should drop. Four big studies were launched to test this idea in different sub-Saharan African countries; a presentation in Durban, South Africa, at the International AIDS Conference last week revealed data from the first of these to reach completion.The study, called Treatment as Prevention (TasP), began in 2012 and enrolled 28,000 people in KwaZulu-Natal, the hardest hit province in South Africa. Sponsored by the French national research agency known as ANRS, TasP tested participants in 22 separate communities, which each had an HIV prevalence of about 30%, every 6 months. In one arm of the study that involved 11 communities, infected people were offered the chance to visit a study clinic near their homes and receive ARVs. Infected people in the 11 communities in the control arm similarly had easy access to a clinic, but they were offered the drugs only if their immune systems had evidence of damage from the virus as defined by government recommendations.center_img Email Sign up for our daily newsletter Get more great content like this delivered right to you! Countrylast_img read more