Ebola lab accident tests experimental vaccine
A lab scientist in Germany accidentally pricked her finger with a needle carrying Ebola virus; there are no approved vaccines for Ebola, and Ebola accidents have killed lab technicians before; the German technician was given an experimental vaccine, and so far developed no symptoms
Did an experimental vaccine save a scientist in Germany from Ebola? The lives of others who work with the deadly virus may well ride on the answer. On 12 March a woman working at the Bernhard Nocht Institute for Tropical Medicine (BNI) in Hamburg accidentally pricked her finger with a needle carrying Ebola virus. There is no approved vaccine for Ebola, and such injuries have killed lab workers before. So she was given an experimental vaccine consisting of a live vesicular stomatitis virus (VSV) carrying an Ebola protein.
The vaccine was being developed by scientists in Canada and the United States mainly to protect lab workers. She has so far developed no symptoms, and doctors now think she is unlikely to. New Scientist’s Debora MacKenzie writes that scientists are still not sure whether it is because the vaccine worked, or because she did not receive enough virus to cause an infection. It should be possible to tell. A vaccine would only prompt the production of antibodies to the one Ebola protein it carries. Infection would produce antibodies to many different Ebola proteins.
Stephan Günther, head of virology at the BNI, says the woman has very low levels of antibodies. These might be caused by the vaccine: when it was tested on monkeys it elicited only low levels of antibodies, but they were enough to protect the animals from Ebola. “We don’t know if this might also result from a mild infection,” Günther says.
The vaccine given to the woman was not a cleaned-up, commercial preparation but an experimental brew that also had proteins from the cultures where it was grown. As a result, she is making antibodies to those as well as to Ebola. It takes very sensitive tests to pick out and characterize the Ebola antibodies. Because the BNI is not developing Ebola vaccine it has no such tests. It may send samples to the U.S. Army Medical Research Institute of Infectious Diseases in Maryland, which does have suitable tests.
Ebola scientists would welcome evidence that the vaccine was safe and effective, but because the woman is now recovering there may not be money to pursue the investigation. If a vaccine company cares to develop it further, “Ebola researchers could volunteer for the safety tests”, says Günther — and become immunized.
