Flu vaccine near 100% ineffective

USA TODAY

Evidence that flu viruses are becoming more resistant to the drug Tamiflu has sown deep concern among doctors who are worried that their best flu treatment is losing its punch.
The spread of resistance also has potentially weakened a pillar of the stockpiles of drugs that will be used to combat global flu outbreaks, doctors say.

The first in-depth analysis of Tamiflu resistance during last year's flu season found that about 12% of people with one of the three strains that caused the most illness, influenza A/H1N1, were infected with resistant viruses. One in five of last year's patients caught the strain, doctors reported Monday.

This year, Tamiflu resistance in that class of viruses has reached almost 100%, turning the tables on a drug designed to defeat resistance. "They're the most common viruses circulating this year," says flu expert William Schaffner of Vanderbilt University. "There are calls coming in from all over the country to infectious-disease doctors and public health specialists asking them how to proceed."