Late diagnosis of HIV and HIV testing in the UK
Late diagnosis of HIV infection continues to be a problem in the UK, because people may be diagnosed with HIV too late to benefit from treatment, or too late to prevent opportunistic infections such as tuberculosis, as we reported earlier this month.
Late diagnosis of HIV is also a problem because people unaware that they are infected with HIV may pass the virus onto others.
Past British HIV Association audits have noted that late diagnosis is a major cause of illness and death for people with HIV in the UK, and several studies have suggested that in some cases diagnoses are being missed in GP practices, as well as in acute and inpatient care services in hospitals primarily due to a perceived barrier in being able to offer HIV antibody testing.
The British HIV Association has now issued new recommendations to reduce the risk of late diagnosis, in partnership with the Royal College of Physicians, the British Association for Sexual Health and HIV and the British Infection Society.
Moving further than last year’s recommendations from BASHH – which recommended opt-out HIV testing in sexual health clinics – BHIVA now recommends that all general practices and acute medicine services should provide diagnostic HIV testing, and such testing should routinely be considered for patients coming in contact with hospital care in non-emergency settings.
However, it is likely to take time before GPs become comfortable with offering the HIV test to patients, and there is still a long way to go before many GPs recognise the potential symptoms of acute HIV infection and feel comfortable about discussing possible risky sexual exposure with their patients.
New networks for HIV care
The new BHIVA standards also recommend that the future model for HIV care in the United Kingdom should consist of `managed clinical networks` - a network of outpatient services and specialist services covering a defined area.
This means that clinics in your district will become part of a network of clinics and other services. Not every service will be offered at your own clinic and you may be referred to other clinics for some specialist services or treatments. The hope is that clinics will share expertise, and patients at smaller centres will get better access to the specialist services that are currently available only at the major treatment centres.
HIV and hepatitis C coinfection
People with hepatitis C and HIV coinfection may not be at higher risk after starting treatment of experiencing liver enzyme increases that indicate liver damage when they are compared with coinfected people not on treatment, according to a large Italian study.
Previously some experts had warned that coinfection could increase the risk of liver enzyme elevations in people starting antiretroviral treatment because of the reduced ability of a damaged liver to process antiretroviral drugs. Several previous studies have found an increased risk for coinfected people, particularly in those with more severe liver damage and those with hepatitis C genotype 3.
The recent Italian study looked at just over five thousand Italian patients, and found that regardless of whether they had started antiretroviral therapy or not, coinfected people were five times more likely to experience a liver enzyme increase during the follow-up period. Men were also more likely to experience liver enzyme increases.
HIV transmission
It’s becoming more widely accepted among HIV prevention researchers outside the UK that a large proportion of HIV transmission takes place very soon after an individual becomes infected, during the months before the immune system brings viral load under some degree of control – the period known as primary HIV infection.
The latest estimate comes from a study carried out in Canada, which was able to use genetic techniques to look at linkages between the viruses of almost six hundred recently infected people in the province of Quebec.
The study found that half of all the infections came from individuals who had themselves been recently infected, and that these infections could be grouped into 75 clusters, highlighting the large numbers of individuals who could become infected from just one highly infectious individual.
In contrast only 12% of the infections could be attributed to individuals on treatment with detectable viral load, suggesting that targeting prevention at people who already know they are HIV-positive may have less effect than targeting people who still believe themselves to be HV-negative.
However, a mathematical modelling study carried out by US researchers suggests that if all gay and bisexual men with CD4 cell counts below 350 could take antiretroviral treatment, the rate of new infections would be reduced by a quarter.
Researchers suggest that more aggressive attempts are needed to identify people with primary HIV infection, including providing more information to people at risk of HIV infection about the symptoms of primary HIV infection.
Some go further, and argue that there are strong grounds to encourage treatment in the newly infected. By reducing viral load during the most infectious phase of HIV infection, the number of new infections could be curtailed.
However there is still no evidence that early treatment of primary HIV infection has any long-term benefit to the individual, so it could be hard to persuade people that they need treatment.
Diagnosing tuberculosis
Tuberculosis diagnosis is more difficult in people with HIV than other people affected by TB for several reasons, and is one of the reasons why people with HIV are disproportionately affected by TB. Skin tests cannot reliably detect latent TB infection in HIV-positive people, there is no test that can yet predict which people exposed to TB will go on to develop it, it can be difficult to detect TB in the sputum of HIV-positive people – for all these reasons TB continues to go undiagnosed, untreated and spreads unchecked among people with HIV.
At present active TB must be diagnosed by obtaining a sample of fluid coughed up from the lungs and airways. A laboratory then attempts to identify TB bacteria in the sputum sample. However in people with HIV the smear test is more likely to fail to identify TB, especially in developing countries.
However, there is a great deal of research going on to improve TB diagnosis. One avenue of research is a TB breath test – a breathalyser-type device. Another avenue is a dipstick-based test that can be used on urine. A third avenue is improving the smear test used to detect TB bacteria in a sample of sputum.