Better surveillance of HIV and hepatitis long overdue
Is the UK doing enough to identify and treat infections by HIV and hepatitis? The evidence suggests that it is not, and that complacency in the face of these threats is unjustified.
Twenty years ago, the trigger for universal antenatal HIV testing in the Tayside and Lothian districts of Scotland was an incidence of 3 per 1,000 pregnant women.
Today England and Wales have undiagnosed HIV prevalences of 15 per 1,000 among men aged between 15 and 44 who have sex with men (MSM), and 5 per 1,000 similarly-aged heterosexuals born in sub-Saharan Africa (SSA).
These estimates come from a Bayesian evidence synthesis on HIV prevalence (diagnosed versus undiagnosed) across exposure groups and for London versus elsewhere in England over the period 2001 to 2008, just published by Presanis et al. in AIDS. They show that targeted offering of HIV tests in general practice, at antenatal and genito-urinary medicine clinics has improved during between 200 and 2008, but clearly by not nearly enough.
The history of surveillance for HIV and hepatitis is one of missed opportunities. At the beginning, the diagnosis of an HIV infection was deemed to be so shocking to people that it was obligatory to offer counseling at the same time as testing. Home test kits were banned.
My late husband Dr A Graham Bird and I wrote a letter to The Lancet in 1994 opposing these regulations and Graham later coordinated a multi-signature letter to the then Chief Medical Officer, Professor Sir Kenneth Calman, on the need for active HIV contact tracing, especially among those newly HIV diagnosed who were also recently infected.
Attitudes towards testing have become more realistic, as The Guardian reported last weekend in a story about the development of small testing kits for use in the home. Those who suspect they may have been infected will be able to put urine or salive on to a computer chip about the size of a USB memory stick, plug it into their computer and get a diagnosis within minutes.
The device has £4 million of funding from the Medical Research Council and its developers hope to make them available for as little as 50p to £1 each in vending machines and in supermarkets. The device recognizes that the reluctance of many young people to visit a genitor-urinary clinic or consult a GP is leaving a lot of STIs undetected.
Graham would have been pleased by the UK’s altered stance and better science on home testing but not that uncontrolled transmission of sexual infections had forced it upon us.
Sixty percent of undiagnosed HIV infections in SSA heterosexuals are women - despite supposedly-universal offering of antenatal HIV tests. HIV is a transmissible, infectious disease with a much longer incubation period to AIDS/death than was the case in the 1990s, thanks to the development highly-active antiretroviral therapies (HAART). Why the diagnosis inertia? We can now both help the patient and prevent onward transmission. What hinders us?
A few years ago when Professor David Goldberg of Health Protection Scotland invited a professional and lay audience at the Royal College of Physicians in Edinburgh to vote on the constituent parts of Scotland’s Hepatitis C Action Plan, the only proposal that met with resounding disapproval was the one (dropped) to offer financial incentives to doctors to increase the number of Hepatitis C diagnoses they made. The Scottish audience considered, as my late husband most certainly did, that control of infectious disease transmission was part of their duty as doctors, not an optional extra.
When it comes to infectious Hepatitis B carriage, it is not only immigrants from SSA but from other countries too (Pakistan, China and eastern Europe among them) who present an unduly high risk - by which I mean that 30 to 50 per 1,000 have infectious Hepatitis B.
In 1996, Graham and I argued for universal offering of Hepatitis B to prisoners, a third to 40 per cent of whom had a history of injection drug use. Scotland implemented this in 1999, since when there has, I think, been no case of acute Hepatitis B infection in a Scottish jail.
Hepatitis B is much more transmissible than is HIV. Unless immigrant carriers are diagnosed, treated and contact tracing is done effectively, UK faces the prospect that its decision not to immunize school-children may need to be revisited. Acceptability was high, I’m told, when Glasgow offered Hepatitis B immunization to all 12 year olds in 2001.
All healthcare workers are required to be immunized against Hepatitis B and provide evidence that they are not carriers – to protect them and their patients. Which other occupations, if any, present a risk to the wider UK population from imported Hepatitis B carriage? Are UK’s surveillance systems, including at detention centres, up to the mark for detecting, registering, treating, contact tracing and immunizing in respect of acute or carrier Hepatitis B?
Imported Hepatitis C, typically acquired through medical treatments or maternally transmitted in certain countries of origin, is believed to have a similar prevalence, that is 30 to 50 per 1,000. Hepatitis C virus (HCV) is 10 times more infectious than HIV, albeit mainly blood-borne and maternally-transmitted but with low rates of sexual transmission.
The same questions apply for HCV as for Hepatitis B – except than there is no immunization to offer, a lower occupational risk outside of healthcare, and greater reliance on treatment of Hepatitis C carriers both to prevent liver progression and to contain onward transmission.
The methodology of Presanis et al. is good, but even better would be its use to answer quintessentially 21st century questions: for example, about the rate of change in the proportion of diagnosed HIV infections that show evidence of HAART-resistance - because these patients are likely to have been infected by a HAART-treated infector. And better still would be to know whether the extraordinary sex ratio of HIV infections in heterosexuals born in sub-Saharan Africa - women are more than twice as likely to be infected as men - reflects HIV status on arrival into the UK, or later.
Graham was always on the case of public health doctors whose analyses stopped short of translation into public health actions. Eight years of data need now to be acted on, surely! Improvements in diagnosis there have been, but far short of what is required in the face of undiagnosed HIV and hepatitis prevalences. What are we waiting for?
The Health Protection Agency should at least be conducting anonymous salivary surveillance studies on volunteers in immigrant communities (500 respondents per sex); in detention centres; and at immigration centres. Participants should, of course, also have the opportunity for confidential attributable blood-testing with appropriate clinical follow-up.
Sheila M. Bird is at the MRC Biostatistics Unit, CAMBRIDGE CB2 0SR