A third case of oseltamivir-resistant swine flu, announced today in Hong Kong, has flu experts worried that resistance to the drug is spreading. Unlike the previous two cases, the Hong Kong patient hadn’t taken oseltamivir herself, which suggests she picked up a resistant strain from someone else.
When Denmark reported its first known resistant case of 2009 A(H1N1) swine flu on Tuesday, scientists weren’t alarmed yet, because the virus most likely developed resistance while the patient was being treated and there was no evidence that she had infected anybody else. A second case, reported yesterday from Japan, also appears to have arisen while the patient took the drug. In the past, such drug-induced mutant viruses have often not spread very well.
