FACTSHEET on Highly-Resistant HIV
Four King County men have tested positive for HIV with strains that are
resistant to several classes of anti-HIV drugs. One of the men was tested
in late 2005, and the other three were tested in 2006. In January 2007,
researchers found these strains to look very similar. Thus, these men
may have had sex or shared injection equipment with common partners.
Since 2000, Public Health has identified 12 other cases of HIV that are
also resistant to several anti-HIV drugs. However, the recent 4 cases
are resistant to many more anti-HIV drugs across more drug classes than
most of the other 12 cases. Since the 4 current cases were infected over
at least one year, this highly resistant form of HIV may be still be spreading
in the community.
What does “drug resistant” mean?
There are four classes of anti-HIV drugs (also called “antiretrovirals”
or “ARVs”), with several drugs in three of the classes. When
HIV meets an anti-HIV drug, it tries to survive by changing its genetic
code. Over time, the HIV virus changes enough to get around the drug and
keep making copies of itself. When HIV can resist one drug, it can often
resist other drugs in the same class. Sometimes HIV can be “drug-resistant”
to several drugs across two or more classes. This kind of HIV is called
“multi-drug resistant HIV” or “MDR-HIV.”
HIV treatment is very complex, and people with HIV must take medications
on a very strict schedule. Resistance can build up if a person does not
follow this schedule or if he/she is not on the correct treatment program.
How did Public Health find out about these cases?
Since around 2000, Public Health has been tracking cases of drug resistance
among people newly-diagnosed with HIV. Two of the four cases were found
during this routine lab testing. The last two cases were found by medical
providers who then alerted Public Health.
Where did this MDR HIV come from?
There is no way to know for sure. We do not know where this strain started
(i.e., who had it first) or how many people in this network came in contact
with this strain through unprotected sex or sharing injection equipment.
Is this a new problem?
Drug resistance is not new. Since 2000, Public Health has identified 16
total cases of multiple class drug-resistant HIV in people recently diagnosed
with HIV in King County. None of the past 12 cases looked as similar to
each other as the current four. About 11% of people recently diagnosed
with HIV who haven’t started treatment have at least some high-level
resistance to at least one of the ARV drugs used for HIV. 3% have shown
high-level resistance to one or more drugs in two or more drug classes.
These rates are similar to other urban areas and have not changed locally
However, the current 4 cases look very similar and share many of the
same patterns of drug resistance. They are highly resistant to two ARV
drug classes and somewhat resistant to a third. Tests on the 4th class
are not back yet. These viruses are closely linked to each other and may
still be in the community.
How do you know this MDR HIV is being spread?
Because the genetic make up of these four cases looks so similar, it is
unlikely that each person developed the exact same resistance pattern
on his own. Also, at least three of the four cases were recent infections.
So this highly resistant strain does seem to be in the community, but
we don’t know how easily it spreads from person to person.
Why does Public Health track HIV drug resistance?
Public Health tracks HIV drug resistance among people who have not started
HIV treatment. This helps us learn what kind of HIV is being transmitted,
how common drug resistance is, and which drugs might become less useful.
This information helps medical providers prescribe HIV therapy more effectively.
Is there more drug resistance happening?
The longer people live with HIV, the longer they are taking HIV drugs.
As more people use more HIV drugs, the chance of drug resistance increases.
Over time, there will be a larger pool of people who might have HIV that
is harder to treat and who may pass HIV to others.
Also, regional testing for resistance is not comprehensive and has not
been conducted steadily since 2000. There are likely to be more cases
than the ones we have been found. We are likely to find more cases of
resistance now that we are looking harder for them.
Does this mean that people with MDR HIV will not be able to get treatment?
No. Some antiretrovirals may still work against MDR HIV, but we don’t
know how well they might work. With MDR HIV, there are fewer drugs to
choose from. These options may also be harder to use, cost more or cause
more side effects.
Does MDR HIV progress faster to AIDS?
We do not know how quickly this virus progresses to AIDS. We have observed
these four cases for only a short time, which is too short to tell how
their disease may progress. At present, each of these cases is early in
HIV infection and does not yet need treatment.
Can people who already have HIV get “re-infected” with MDR
Yes. People who already have one strain of HIV can get a different strain.
The second strain could be drug-resistant or not. Getting MDR HIV on top
of existing HIV may cause current medications to stop working. It could
also limit future treatment options and impact health.
What is happening with these individuals?
Public Health is working with these individuals and their medical providers
to locate and test sexual and drug partners for HIV infection and drug
What Should I Do?
If you are a medical provider:
• Conduct drug resistance testing in all patients with newly-identified
HIV. Report all cases of multi-drug resistant HIV to Public Health.
If you are HIV-negative or have not tested in the last 6 months:
• Use condoms every time you have sex.
• Use your own drug injection equipment.
• Ask sex and drug partners about their HIV status. Find out your
current status and share that with your partners.
• Get tested regularly for HIV. How often is that?:
• Every 3 months for gay and bisexually active men who:
? Have had anal sex without a condom with a man who has HIV or whose HIV
status is unknown.
? Have recently had a sexually transmitted disease (STD).
? Use methamphetamine.
• Once a year for other people at sexual or drug-related risk for
HIV (i.e., people who inject drugs, have STDs, or have multiple sex partners).
If you are living with HIV:
• Use condoms every time you have sex. Even if your partner has
• Use your own drug injection equipment.
• Share your HIV status with sex or drug partners. Ask them about
• Find out if you have drug resistance before starting treatment
or if your anti-HIV drugs don’t seem to be working.
• Take your medications on schedule. If that’s hard to do,
talk to your doctor about options.
For more information about drug-resistant HIV or where to get tested for
HIV, call the HIV/STD Hotline Monday – Friday, 9am – 4pm:
(206) 296-4843 TTY
Other useful websites: www.hivdrugresistance.com