World AIDS Day events fo­cus on 'get­ting to zerp.'

GA Voice - - FRONT PAGE - By Matt Schafer

World AIDS Day, Dec. 1, features the slo­gan “Get­ting to zero: zero new HIV in­fec­tions, zero dis­crim­i­na­tion, zero AIDS re­lated deaths” for the years 2011 through 2015.

While it is un­likely the “zero” goal will be reached by 2015, three decades of HIV anal­y­sis has sparked a “re­nais­sance” of med­i­cal re­search that is lead­ing sci­en­tists in new di­rec­tions in their search for an ef­fec­tive vac­cine.

Dr. Wayne Koff, the chief sci­en­tific of­fi­cer for the In­ter­na­tional AIDS Vac­cine Ini­tia­tive, started re­search­ing HIV shortly af­ter the first cases be­gan ap­pear­ing some 30 years ago.

“We’ve seen in the last three or four years a plethora of data that we in the AIDS vac­cine devel­op­ment field are call­ing a re­nais­sance, and as some­one who has been in the field since the be­gin­ning I don’t use that term lightly,” Koff said.

It took al­most 20 years of re­search to get AIDSVAX, the first po­ten­tial vac­cine, into hu­man test­ing in 2003. While that vac­cine didn’t re­duce vi­ral load, Koff said it was im­por­tant be­cause “it proved that we could safely con­duct an HIV hu­man ef­fi­cacy trial.”

That trial even­tu­ally paved the way for the 2009 Merck RV144 trial in Thai­land. That study in­cluded more than 16,000 par­tic­i­pants stud­ied over a course of six years.

“In a sur­prise to many of us in the field, this showed a mod­est ef­fi­cacy of 31 per­cent when com­pared to con­trol group,” Koff said. “While that wouldn’t re­sult in a work­able vac­cine be­cause the ef­fi­cacy was only 31 per­cent, it did show that a vac­cine was pos­si­ble, and there have been sev­eral stud­ies ex­am­in­ing why that vac­cine was ef­fec­tive.”

Ac­cord­ing to the In­ter­na­tional AIDS Vac­cine Ini­tia­tive there are at least 37 dif­fer­ent vac­cine trails cur­rently un­der­way across the globe, each ex­plor­ing dif­fer­ent po­ten­tial cures, and each pro­vid­ing key in­for­ma­tion in the search for an ef­fec­tive vac­cine.

Koff said that in or­der to make a prod­uct that could be given to the pub­lic, a vac­cine would have to be at least 50 per­cent ef­fec­tive in test­ing. For ex­am­ple, the Cen­ters for Disease Con­trol & Preven­tion es­ti­mates that the yearly flu vac­cines have ef­fi­cacy rates of around 50 to 70 per­cent.

‘Dif­fer­ent virus in each per­son’

Find­ing a vac­cine for HIV has proven so dif­fi­cult in part be­cause of the na­ture of the virus. Be­cause of its abil­ity to change, HIV has re­quired a new ap­proach.

“Be­cause this virus mu­tates so much we can’t just use the old form of us­ing a weak­ened form of the virus,” Koff said. “The measles vac­cine that’s li­censed is just a weak­ened form of measles. The li­censed po­lio vac­cine is a weak­ened ver­sion of po­lio, but HIV is a crafty virus… and we learned a long time ago that you can’t just take a weak­ened ver­sion of HIV.”

Viruses are non-liv­ing pieces of pro­teins wrapped around ei­ther DNA or RNA. Viruses can­not re­pro­duce on their own, and so they in­vade cells and take over the cell’s ma­chin­ery to make copies of them­selves, which of­ten de­stroys the cell in the process. Be­cause HIV is an RNA virus it has been es­pe­cially dif­fi­cult to treat.

“It is an RNA virus which is prone to mak­ing mis­takes, un­like DNA. If it makes too many mis­takes then it stops be­ing HIV, but if it makes a stan­dard amount of mis­takes that RNA repli­ca­tion typ­i­cally makes, it changes the amino acids, and makes a dif­fer­ent virus,” Koff said. “HIV is dif­fer­ent across the world, and the iso­lates are very dif­fer­ent in each in­di­vid­ual. It’s es­sen­tially a dif­fer­ent virus in each per­son.”

Be­cause of that, re­searchers have dif­fer­ent ways to stop the virus, and many of the vac­cine can­di­dates tar­get the protein cap­sule that car­ries the DNA. Koff said re­searchers are find­ing more sites on HIV that are unique to that virus and can be blocked by broadly neu­tral­iz­ing an­ti­bod­ies.

Think of a lock and a key, Koff said. If you have a mol­e­cule of a T-Cell, that part is only go­ing to go into a re­cep­tor on HIV. If re­searches can bind that site and keep that virus from in­fect­ing the cell, the spread of HIV in the body can ef­fec­tively be stopped, Koff ex­plained.

Hu­man tri­als un­der way

An­other fac­tor that makes the virus more deadly is that it in­fects T-Cells, a type of white blood cell that is a crit­i­cal link in the body’s im­mune sys­tem. At­tack­ing the T-Cells and us­ing them as a host helps al­low the virus to spread, and leaves the body open to sec­ondary in­fec­tions.

A former Emory Univer­sity re­searcher, Dr. Ha­ri­ett Robin­son has been ex­plor­ing a mul­ti­stage at­tack that she thinks could re­sult in a vac­cine that could not only keep peo­ple from be­ing in­fected, but re­duce the vi­ral load in peo­ple who are al­ready HIV pos­i­tive.

Robin­son has worked on the vac­cine for over a decade and has moved to GeoVax, a pri­vate com­pany ded­i­cated to mak­ing a vac­cine, where she serves as chief sci­en­tific of­fi­cer.

Her vac­cine con­sists of DNA mod­i­fied to prime an im­mune re­sponse and an in­ert virus that could boost an im­mune re­sponse.

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World AIDS Day, Dec. 1, features the slo­gan ‘Get­ting to zero: zero new HIV in­fec­tions, zero dis­crim­i­na­tion, zero AIDS re­lated deaths.’

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