Health News - Resistance to HIV drugs in UK increasing, and among highest in the world
25 November 2005 - written by Mark Pownall for Bupa's health information team
People infected with HIV in the UK have some of the highest rates of resistance to anti-HIV drugs, according to a new study published in the British Medical Journal.1 The findings have increased concern that in future, without a change in behaviour towards safer sex, there may be a new epidemic of drug-resistant HIV.
How was the study carried out?
Researchers took blood samples from 2357 people infected with HIV who had not yet embarked on anti-HIV treatment.1 The samples were tested to see if the HIV was resistant to the effects of three main forms of drug treatment. Tests were done on patients between 1996 and 2003, so researchers were able to track any changes in their resistance to the drugs as time went on.
What did the study show?
They found that 335 people, or 14.2% of those who took part, showed some degree of resistance to one or more of the drugs currently available.1 The majority were resistant to just one class of drugs. However, 44 cases showed resistance to two classes of drugs and 34 patients were resistant to all the drugs that are commonly used to combat HIV.
The UK's rate of resistance is among the highest in the world. It is much higher than in the USA where 7% of patients with HIV show resistance to the antiviral drugs. In Europe, around 10% of patients with HIV have some resistance to the drugs.
Is resistance becoming more common?
Yes. In the latest year for which the researchers had figures (2002-3), nearly 1 in 5 of patients with HIV were resistant to one or more of the available anti-viral drugs.1
Why were the researchers concerned?
If lots of patients with HIV become resistant to available drugs, there will be fewer treatment options available. This could mean that more people with HIV/AIDS die. Researchers are concerned that there could be another epidemic of drug-resistant HIV. There are also concerns that the rise in resistance may mean that HIV is being transmitted by patients who know they are infected. This could reflect a worrying trend that more people with HIV are no longer practising safer sex.
How does the HIV virus become resistant to drugs?
Anti-HIV drugs work to block chemicals called enzymes essential to the survival of the virus. When the DNA (the genetic code) of these enzymes changes, the enzymes become slightly different. Drugs are then less effective at 'recognising' the enzymes and acting against them.
Why can drug resistance lead to an epidemic?
If there are forms of HIV that are resistant to drug treatment, they are more likely to survive and infect other people. Resistant forms of HIV are able to spread more easily and infect more people.
How many people in the UK currently have HIV?
There are at least 53,000 people with HIV infection in the UK.2 There are an estimated 7258 new diagnoses per year.
Is this number growing?
Yes. This is largely because of a steep rise in the number of heterosexually-acquired HIV infections.
How many people around the world have HIV?
A new study from UNAids, the Joint United Nations Programme in HIV/AIDS, estimates that there are 40.3 million people across the world with HIV. Five million people were infected this year alone.3
Who is affected?
In the UK, around 4 in 5 people infected with HIV are men.2 Sex between men is probably the cause of 59% of HIV transmission. Heterosexual sex is responsible for another 28%.2 Injected drug use causes about 6% of HIV cases, while mother-to-child transmission causes 3% and blood or tissue contamination causes 4%.2
How many people died of AIDs-related illness in the UK in 2004/5?
About 467 people in the UK died from AIDS in 2004, and 305 died in the nine months to the end of September 2005.4 This is a dramatic fall from the 1467 people who died in 1996 before modern HIV drugs were available.
How is HIV transmitted?
HIV is a virus transmitted in body fluids. Sexual intercourse between gay men and heterosexual men and women is the most common way it is transmitted.5 It is also transmitted by direct blood-to-blood contact - for example, when drug misusers share dirty needles.
What are the available therapies?
There are three main classes of drugs. These block two key enzymes of HIV: reverse transcriptase and protease. The therapies are usually used in combination and have had a remarkable effect on slowing progression of infection and preventing death.
Is it curable?
No. However, combination therapy can reduce levels of HIV where even the most accurate tests cannot detect its presence in the blood. People infected with HIV now live for many years with their infection under control.
Can you prevent infection?
The most effective way to prevent infection is not to have sex or to have safer sex. Intravenous drug misuse also poses a risk of infection if needles are shared.
What is safer sex?
When there is no transmission of body fluids, sex is safer and will not spread HIV infection. Use of a condom during vaginal or anal sex reduces the risk of HIV transmission. HIV can be transmitted during oral sex, but this is rare.6
Bupa Information:
Further information
- Terrence Higgins Trust
0845 1221 200
www.tht.org.uk - NAM (National AIDS Manual)
020 7840 0050
www.aidsmap.com
References
- Time trends in primary resistance to HIV drugs in the UK. Multicentre observational study: UK Group on Transmitted Drug Resistance, David Dunn. BMJ Online First doi:10.1136/bmj.38665.534595.55. http://bmj.bmjjournals.com
- Health Protection Agency, Epidemiology - HIV and AIDS. October 2005. www.hpa.org.uk
- AIDS Epidemic Update 2005. Joint UN Programme on HIV/AIDs and the World Health Organisation. www.unaids.org
- HIV and AIDs in the UK; Quarterly update. Data to the End of September 2005. Health Protection Agency For Infection. www.hpa.org.uk
- Avert. United Kingdom HIV and AIDS statistics by Exposure Category. www.avert.org/stats.htm
- Avert. Transmission - Oral sex. www.avert.org/orlsx.htm
All pages were accessed on 20 November 2005
