Dried blood spots contaminated with hepatitis C virus (HCV) and left on inanimate surfaces can remain infectious in ordinary room temperatures for up to six weeks, aidsmap reports. Normal cleaning products can reduce this infectivity, but not when they are improperly diluted. Publishing their results in the Journal of Infectious Diseases, researchers from Yale University attempted to “closely simulate” the conditions of a hospital setting in an attempt to explain those cases of hep C transmission that occur in a hospital despite any surgical or blood product exposure.

The investigators put blood spots containing potentially infectious levels of hep C onto plates and dried them, then stored them either at 39 degrees, 72 degrees or 100 degrees Fahrenheit for up to six weeks. They also determined how effective three commercially available cleaning products, including bleach, CaviCide and ethanol, were at reducing the infectivity of the blood spots.

At 100 degrees, the virus retained its infectivity for up to a week. This range was extended to six weeks for the blood spots stored at 39 and 72 degrees. At these lesser temperatures, the infectivity dropped markedly during the first two weeks, although low levels of infectious hep C remained up to the six-week mark.

Exposing the blood spots to one minute of an antiseptic was 100 percent effective in the case of bleach diluted at a ratio of 1:10, 94 percent effective with CaviCide similarly diluted, and 87 percent effective with ethanol at a concentration of 70 percent. If these cleaning products were diluted, their effectiveness was reduced significantly.

To read the aidsmap story, click here.

To read the study abstract, click here.