US government funding of new research involving flu viruses and other pathogens in which scientists deliberately make them more transmissible or more deadly has been temporarily halted.

The White House’s Office of Science and Technology Policy said the halt in funding would affect research and experiments involving flu, SARS and Middle East respiratory syndrome (MERS) viruses.

Studies involving naturally occurring flu, MERS and SARS viruses are unaffected “unless there is a reasonable expectation that these tests would increase transmissibility or pathogenicity,” the statement said.