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NCD Now: Acute HIV Testing
Early detection is crucial in treating many illnesses and improving a person's chances of survival. The human immunodeficiency virus, or HIV, is no different. That's why North Carolina is now testing for the earliest stages of the infection, and it was the first state in the country to do so.
More than 100 thousand blood samples pass through the state's HIV testing laboratory each year, coming from all across North Carolina to be screened for the virus that causes AIDS. But before one particular type of test was available, some people might not have gotten the right results.
Dr. Peter Leone/UNC-CH School of Medicine and Medical Director, HIV/STD Prevention & Care Branch: Our traditional ways of detecting HIV were dependent on an antibody response, so this is a period that we can miss because of that.
This period is called acute HIV, a time when someone is infected but the body's immune system has not yet begun attacking the virus, making it impossible to detect with a standard test.
Dr. Leone: It takes about four to eight weeks after that happens for the body's immune system to really respond and produce antibodies that we can detect. So acute HIV really refers to this window of time where the virus, HIV, is replicating without much control from the body's immune system. As a result it is the most infectious period of HIV. Period. it's a very short window of time we're talking about, yet some estimates put as much as 40 to 50% of transmission occur during this acute period.
That's why, in November 2002, the state began testing for acute HIV. Any blood sample that tests negative with the standard antibody test also gets the acute test.
Dr. Leone: We take blood samples from individuals who tested antibody negative and pool them into pools of, in this case, of 100, and we test that pool of 100 for the virus itself.
Then, if the pool is positive, technicians can break it down and find the infected sample, someone who otherwise might have been told he or she did not have HIV. Dr. Peter Leone, Medical Director for the state HIV/STD Prevention and Care Branch, says the pooling procedure helps to control costs. The program costs three to four hundred thousand dollars a year, or between two and three dollars for each acute HIV test.
Dr. Leone: But when you start thinking about is it worth the extra two bucks or three bucks per test to identify people that could be missed for years, I think the overwhelming answer to that is yes.
When technicians in the lab discover a case of acute HIV, another team of people goes to work - the disease intervention specialists.
Todd Vanhoy/Field Services Manager: A disease intervention specialist is basically a counselor and an investigator at the same time. On the investigation side, we follow up on any reports of positive STDs, basically now it's HIV and syphilis, and we follow up with the individual, refer them into care, offer counseling services to them.
Todd Vanhoy oversees the state's disease intervention specialists and works closely with county-level disease investigators as well. He says when it comes to acute HIV, it's critical to act fast, In part so the infected person will not unknowingly infect anyone else.
Todd Vanhoy: What we're trying to do is get to them extremely fast. As soon as we get the report we follow up. Within 24 hours a worker will be trying to find that individual, to get them in, to get them in to UNC or another infectious disease clinic to get them some possible care that may help them fight off the infection.
Specialists also talk with the patient about their sexual partners. North Carolina law says those partners must be told they've been exposed to HIV.
Todd Vanhoy: A lot of times people, without this service, would never know. You'd never know you've been exposed. People are generally uncomfortable about providing that I'm positive to a partner because that word can be spread about in the community, so us doing that, we provide that service and we can do it confidentially.
And, he says, possibly save that partner's life.
Todd Vanhoy: If we can get to a person's partner quick enough we can possibly give them medicine to prevent them from ever getting the infection or developing it.
Dr. Leone says protecting people's partners is just part of the benefit of acute HIV testing.
Dr. Leone: You have people coming in for HIV testing. They want to know if they're infected. We know we have a scheme or a way at least to identify these folks during this period, we should try to do everything we can to identify folks when they come in and tell them yes you're infected or no you're not. To have folks come in to us and tell them you're probably not infected, we want you to come back in three months, a lot of individuals just assume they're not infected. We could lose those folks for years.
He says the testing also lets investigators see where transmissions are occurring and among what groups of people.
Dr. Leone: That allows us to be very focused in interventions. We know where those transmissions occur. We can then look at risk groups and plan interventions that are targeted geographically and with very specific messages to get that at risk population.
And he says acute HIV testing has already helped to protect at least one unborn baby, at risk for the disease but powerless to protect itself.
Dr. Leone: Identifying her [the mother], getting her on therapy, and preventing transmission saved probably, never mind the fact that the baby benefited, the cost of that one child would have been about 250-thousand over the course of that kid's lifetime. So we prevented transmission and we saved the state money.
Dr. Leone says since November 2002, the program has identified more than 100 other people with acute HIV and possibly prevented hundreds more from being infected with what is still a deadly disease.
Dr. Leone: This sort of new model is very different than anything that's been done in HIV anywhere in the world, and we think that it puts NC in a real advantageous position to do something about the epidemic.
Dr. Leone says finding transmission trends through acute HIV testing has also helped the state to attract about three million dollars in federal funding for specifically targeted prevention efforts. |
