UK faces new Aids fear

HIV is very good at adapting to beat the drugs that fight it

The UK is not doing enough to address the worrying spectre of a rise in new strains of HIV which are resistant to treatment, says an expert.

Some British patients are resistant to one or more of the current anti-retroviral drugs used to treat HIV.

A small number do not respond to any of them.

The drugs have been credited with reducing HIV to undetectable levels in many people and have had a dramatic impact on death rates from Aids.

There have been reports that this has led to growing complacency among the public and that many people wrongly believe the medication represents a cure for Aids.

Jeffrey Williams, health promotion officer at the Terrence Higgins Trust, says only two London hospitals have money in this year's budget to carry out routine testing for resistance.

The tests are expensive - at around £200-£300 a go - but Mr Williams says this may be cheaper than putting people on a course of drugs which does not work.

A year's worth of drugs costs around £6,400. Experts usually allow patients between two and four months to see if they respond to the drugs.

In the meantime if the drugs do not work they may fall ill.

Mr Williams said: "Testing for resistance may save time and money in the long run."

Mutations

Resistance testing falls into two main types: genotypic and phenotypic tests.

Genotypic testing looks at changes in HIV. The virus is very good at adapting itself to try and outsmart the drugs used against it.

If mutations are noted, scientists then have to study how that might affect drugs' ability to fight the virus.

Phenotypic testing involves growing the virus in the presence of an anti-retroviral drug.

Scientists then measure how resistant the virus is to the drug.

Anti-retroviral drugs have dramatically reduced deaths from Aids

Two US studies published last week found resistance was growing.

One found that 3.8% of a sample of newly infected patients had multi-drug resistance.

In the UK, very little research is being carried out into prevalence of drug resistance.

"We know it exists, but we don't know how much it is," said Mr Williams.

"Only by funding tests will we learn how big a headache it is likely to be."

He added that if the UK had similar figures to the US that could mean quite a few people were already resistant to treatment.

Some 2,000 new infections occur every year in the UK.

And he warned that the percentage affected was likely to rise as drug-resistant strains were passed on, although drug companies are producing around two new drugs a year in an effort to keep ahead of the virus.

Safer sex

Mr Williams said the threat of drug resistance meant more efforts had to be put into safer sex messages and to supporting people taking their drugs.

Failure to take the full course of anti-retroviral drugs or incorrect dosage is thought to be the reason for resistant strains of the virus emerging.

Experts say it drug regimes are hard to follow.

They often involve a lot of drugs which have to be taken daily for the rest of a person's life. Some have specific conditions attached to them, such as having to be taken at certain times of the day.

THT has trained volunteers to help patients take their medication.