While the past decade has seen great strides in medical technology, it hasn't seen solutions to all of our health problems.
Some of these threats turned out to be almost nonexistent. Others were arguably overblown. Some caused widespread harm.
So what new threats have been robbing you of sleep since the annual odometer rolled over from 1999 to 2000? Join us as we take a look at the top ten new threats of the last ten years.
Since it came to public attention in the United States in April, the largest health scare of 2009 has been swine flu.
While other forms of the virus typically peak in February and largely affect the elderly, this strain of the H1N1 flu virus came out of season and mostly affected younger people.
In June, the World Health Organization declared the virus a pandemic, meaning that it was widespread on multiple continents.
Manufacturers began producing vaccine at the end of the spring, but there were shortages nationwide, even late into the fall.
While the majority of cases of the flu have been mild, thousands of American deaths have been attributed to the virus.
But no matter the severity, many health experts agree there are lessons to be learned.
"We just have to note, and this was a bit scary, that when H1N1 came along in communities... our capacity to take care of [patients] was stretched," said Dr. William Schaffner, Chair of the Department of Preventive Medicine at Vanderbilt University Medical Center. "We don't have a lot of reserve in the health care system anymore."
While much of the alarm over the chemical bisphenol A, or BPA for short, has come lately, scientists have been looking at it for years.
In January of 2000, an article in the Journal of the American Dental Association discussed how BPA -- which is used in some dental sealants -- was not found at detectible levels in the body more than a few hours after the treatments.
Since then, studies have shown the chemical to cause birth defects in lab animals, and even create some problems in humans in high doses. The chemical, used in household plastics, has also been found in babies, leading to increased scrutiny from regulatory bodies.
But while we know it is present in humans and can create problems at high levels, it remains unclear what the effect of BPA is in humans at lower doses.
"I would say that there's growing evidence that it is a significant concern, but it's not clear yet how much of a concern," said Joel Schwartz, a professor of epidemiology at the Harvard School of Public Health and director of the Harvard Center for Risk Analysis. "There's a lot of things that still need to be understood, but there's certainly enough things to say, 'Yes, this is something that needs to be on our radar screen.'"
In 2007, a number of products made in China were recalled -- but perhaps the recall that drew the most attention was of children's toys containing lead paint, including some from the popular Thomas the Tank Engine line.
The problem wasn't so much one of scientific analysis as it was of enforcement.
"We do know that lead is bad for you," said Schwartz. "Kids and toys are a bad place to put that exposure together. That's a case where that's just outrageous."