Clinical management of low-level hepatitis B surface antigen in haemodialysis patients with a recent history of HBV vaccination – the results of a UK-wide survey

Identifying transient low-level hepatitis B (HBV) surface antigen (sAg) post-vaccination is a well-established phenomenon in haemodialysis patients. These results create a clinical conundrum; should patients be deemed potentially infectious, requiring further testing and heightened infection control precautions, or should negligible risk be assumed? National guidance covering this scenario is lacking; therefore we conducted a survey of the clinical practice of UK virology departments. Thirty-six laboratories were contacted and 17 responses received (47 %). Eleven responders had observed sAg positivity post-vaccination, for a maximum duration of 3 weeks. Clinical management was highly variable. Only 3 hospitals had specific written policies, with others following an internal consensus or a standard protocol for sAg positive patients without recent vaccine. Further testing consisted of HBV serology (3/11), HBV PCR (1/11) or PCR and serology (7/11). Three departments were highly risk averse, recommending universal isolation with dedicated dialysis machines. Two departments did not advise additional precautions and 5 based decisions on risk factors e.g. foreign travel. Heightened precautions were stopped on the basis of negative serology (1/11), PCR (5/11) or serology and PCR (2/11). To summarise, vaccine-derived sAg positivity is commonly encountered on haemodialysis units. Recommendations on the interval between vaccination and testing would alleviate the issue, with this study suggesting a minimum of 3 weeks. Infection control precautions varied considerably. In most cases, patients are risk assessed for isolation as a minimum; however this may depend on local expertise and the availability of isolation facilities. It is clear that national guidance would standardise patient care.