Infectious disease rates are high among homeless people

Rates of the infectious diseases HIV, Hepatitis C and tuberculosis among the world’s homeless people are many times higher than in the general population, according to a new systematic review of existing data published Online First in The Lancet Infectious Diseases.

The study – which examined more than 40 research papers assessing the levels of HIV, hepatitis C and tuberculosis among homeless people from 1984 to 2012 – found that although there is considerable variation between countries and regions, homeless people have a much higher likelihood of having one of these potentially fatal and debilitating diseases.   There are thought to be more than 650000 homeless people in the US and around 380000 in the UK, with rates of family homelessness increasing in the US and youth homelessness rising in the UK.

In the US, the prevalence of tuberculosis is at least 46 times greater in the homeless population than the general population, and the prevalence of hepatitis C viral infection is increased more than fourfold.  In the UK, the prevalence of tuberculosis is at least 34 times greater in homeless people than in the general population, and the prevalence of hepatitis C viral infection is nearly 50 times greater.  For HIV, they were typically 1-20 fold higher in US homeless people than the general population, but no studies were found in the UK.  Similar patterns were observed in most other countries for which data were available.

According to the senior author, Dr Seena Fazel, a Wellcome Trust Senior Research Fellow in Clinical Science at the University of Oxford, “Infections in homeless people can lead to community infections and are associated with malnutrition, long periods of homelessness, and high use of medical services. Because absolute numbers of homeless people are high in some countries, improvements in care could have pronounced effects on public health.”

The authors focused on the global prevalence of HIV, Hepatitis C and tuberculosis, because preliminary work revealed that these are the most heavily studied infectious diseases among homeless populations.  However, they point out that high rates of other infectious diseases – such as hepatitis A and B, diphtheria, foot problems and skin infections – have been reported in some studies, suggesting that further research is urgently needed to assess the scale of the problem and allow public health efforts to be appropriately targeted.

The authors also advocate a more active approach to identifying tuberculosis patients in particular, with Dr Fazel adding, “Screening for tuberculosis should be done through active case-finding—it should not be restricted to symptomatic people presenting to health services, which happens less and later in marginalised groups than in general populations.” More effective treatment and management should be considered including syringe and needle exchange programmes, first-aid centres in large cities, and annual snapshot interventions of homeless populations.

In a linked Comment, Dr Didier Raoult of the University of Aix-Marseille, reinforces this point, commenting that, “Targeted actions are needed to address the susceptibility of homeless people to infection.  The risks of epidemics of infectious diseases in homeless populations remain significantly higher than those in the general population in the same country. These increased risks are a public health challenge for the population as a whole. Implementation of specific strategies to reduces these risks is crucial.”