Nearly a third of all prescriptions written for antibiotics are just not needed, according to a new report issued Tuesday.
Despite decades of ever-more-frantic warnings from health officials, doctors are still writing prescriptions for colds, ear infections and bronchitis, even though they do not help, the Centers for Disease Control and Prevention said.
And these unneeded antibiotics are helping drive a surge in drug-resistant superbugs, CDC said in the report, issued jointly with the Pew Charitable Trusts.
"Antibiotics are lifesaving drugs, and if we continue down the road of inappropriate use we'll lose the most powerful tool we have to fight life-threatening infections," said CDC Director Dr. Tom Frieden.
"Losing these antibiotics would undermine our ability to treat patients with deadly infections, cancer, provide organ transplants, and save victims of burns and trauma."
The researchers took a deep dive into data on antibiotic prescriptions written in 2010 and 2011— the most recent data they could work with.
About 13 percent of all outpatient doctor visits - that would add up to 154 million visits a year— result in an antibiotic prescription, they found. And nearly 30 percent of these prescriptions, or 47 million of them, are unnecessary, they calculated.
These include about half of the millions of prescriptions written for acute respiratory conditions, such as sinus infections, middle ear infections, sore throats, colds, bronchitis, bronchiolitis, asthma, allergies, influenza, and viral pneumonia.
"Sinusitis was the single diagnosis associated with the most antibiotic prescriptions per 1,000 population," they wrote in their report, published in the Journal of the American Medical Association. Drugs are not usually needed to treat sinus infections, which are often caused by fungi that are not affected by antibiotics.
"Up to 70 percent of people with acute sinusitis recover without any prescribed medications," the American Academy of Allergy, Asthma and Immunology says on its website.
Antibiotics do nothing to help a viral infection, even though patients often strongly feel they will and badger doctors for a prescription.
"Children younger than 2 receive the most amount of antibiotics," Dr. David Hyun, a senior officer at Pew and a pediatric infectious disease specialist, told NBC News.
It's not just a waste of money. Every time someone uses an antibiotic, the bacteria in their body begin to evolve resistance to it. It's impossible to wipe out every single bacterium in the body, so those that survive are stronger, and can not only re-infect the patient, but can be passed to others.
That means the antibiotic doesn't work as well the next time.
Even before penicillin was introduced in 1943, Staphylococcus germs were identified that were resistant to its effects. Just nine years after tetracycline was introduced in 1950, a resistant strain of Shigella evolved. Methicillin-resistant Staphylococcus aureas (MRSA) evolved just two years after methicillin hit the market in 1960.
"A lot of the procedures we take for granted things like chemotherapy, dialysis, or even hip replacement surgery, would become a far more dangerous process if we don't have effective antibiotics," Hyun said.
"It could be life or death," he added. "We don't want to be faced with a situation where we're trying to treat an infection that is so resistant we don't have any antibiotics to use."
And people wipe out "good" germs in their digestive tracts and on their bodies every time they use antibiotics. It's the loss of these beneficial bacteria that helps Clostridium difficile thrive. C. diff infects 450,000 Americans a year and killed 29,000 in 2011.
"The rise of antibiotic resistance is a global crisis. It's one of the greatest threats to health today," WHO director-general Dr. Margaret Chan said last November.
The CDC says more than two million people are infected by drug-resistant germs each year, and 23,000 die of their infections.
The White House has made better use of antibiotics, and the development of new antibiotics, a priority.