At room temperature, hepatitis B viruses (HBV) remain contagious for several weeks and they are even able to withstand temperatures of 4°C over the span of 9 months. When applied properly, disinfectants are effective—but only undiluted. These are the results gained by a German-Korean research team in a study using a novel HBV infection system in human liver cells. Due to a lack of human research models, research had previously been conducted in duck HBV. Professor Eike Steinmann from the Department for Molecular & Medical Virology at Ruhr-Universität Bochum (RUB) and RUB alumnus Professor Marc Windisch from the Institute Pasteur Korea in Seoul published their report in the Journal of Infectious Diseases on October 24, 2018.

Recurring infections

Hepatitis B is primarily transmitted through contact with blood. “Consequently, it should be easy to control, provided appropriate hygiene measures are implemented,” says Eike Steinmann. However, there are frequently cases of people contracting HBV in hospitals or in the workplace.

Previously: Duck viruses only

Attempting to find out why, researchers had hitherto been forced to make use of the duck HBV, which is related to the human virus. “However, those studies have only ever permitted rough estimates as far as the infectiosity of HBV is concerned,” points out Steinmann. For their analyses, he and his colleagues utilized an HBV infection system in human liver cells, developed recently at the Institute Pasteur Korea, in order to obtain more realistic results. “The new HBV infection system enables researchers worldwide to finally conduct highly detailed studies of the human virus that had not been possible until quite recently,” explains Marc Windisch.

Common hand disinfectants are effective

Using this model, the researchers were able to demonstrate that the infectivity of HBV barely decreases at room temperature even after a few weeks, and that it remains highly stable at 4°C over a period of 9 months. “Various alcohols and off-the-shelf hand sanitizers deactivate the viruses,” says Eike Steinmann. “If the disinfectants are diluted, however, their deactivating properties are reduced. Luckily, diluting disinfectants is not common practice.”

More resilient than all others

The researchers compared the efficacy of two alcohol-based WHO-recommended hand sanitizers against different viruses that have an envelope, such as the HBV. The comparison viruses included the Ebola virus and the hepatitis C virus. “Among all tested viruses, HBV demonstrated the highest resilience against both disinfectants,” stresses Marc Windisch, head of the Applied Molecular Virology Laboratory at the Institute Pasteur in Seoul.

The researchers recommend strict compliance with hygiene guidelines, in order to prevent HBV infections in the future.