Here are some of the latest health and medical news developments,
compiled by editors of HealthDay:
UnitedHealth, Humana Leaders in Medicare Drug Plan Sign-Ups
Two companies -- UnitedHealth Group and Humana -- are the frontrunners among insurers enrolling people for the new U.S. Medicare drug benefit.
About 90 companies are administering more than 3,000 plans, but a handful of companies are pulling in the bulk of enrollees, according to the Centers for Medicare and Medicaid Services.
The leader is UnitedHealth, which has a joint marketing relationship with AARP. The company has enlisted 3.8 million people, which represents 27 percent of the enrollment so far in stand-alone drug plans, the Associated Press reported.
UnitedHealth is also first in Medicare Advantage offerings, with 20 percent (1.2 million enrollees) of the market share.
Humana is second in the market in stand-alone drug plans, with about 2. 4 million beneficiaries (18 percent). The company ranks third in terms of Medicare Advantage offerings, with about 800,000 enrollees (13 percent), the AP reported.
Companies with the largest number of people enrolled at an early stage will have a major marketing advantage later on, noted Dan Mendelson, president of the consulting firm Avalere Health.
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U.S. Mad Cow Testing Likely to be Scaled Back
Testing data released Friday indicates that only four to seven cows in the United States have mad cow disease, according to Agriculture Secretary Mike Johanns.
"The data shows the prevalence of BSE (bovine spongiform encephalopathy) in the United States is extraordinarily low," he said during a conference call with reporters. "In other words, we have an extremely healthy herd of cattle in our country."
Johanns said it's likely that testing for BSE will be scaled back after the data is reviewed by an independent panel of scientists, the Associated Press reported.
After mad cow first appeared in the United States a few years ago, testing increased to about 1,000 samples per day from a prior level of about 55 samples a day, the AP reported. U.S. officials haven't made a decision about the new level of testing. International guidelines call for about 110 tests a day.
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Gene Therapy for 'Bubble Boy' Syndrome May Cause Cancer
Gene therapy to treat children with no immune system -- a condition called X-SCID that's commonly referred to as "bubble boy" syndrome -- may increase cancer risk, says a U.S. study in the journal Nature.
Children with X-SCID have a mutated IL2RG gene. The defective gene is unable to produce a protein needed for the development of immune system cells, which means the immune system cells can't develop normally and protect the body.
The gene therapy replaces the defective IL2RG gene.
In this study, researchers at the Salk Institute for Biological Studies in La Jolla, California, injected mice with the same gene therapy used to treat X-SCID, BBC News reported.
The mice were monitored for 18 months. A third of them developed lymphoma.
Critics of the study say the researchers used unnaturally high doses of the gene therapy, BBC News reported.
A French study of the gene therapy in 10 children had to be halted in 2002 because three of the children developed T-cell leukemia.
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U.S. Has Mild Flu Season
The fact that this year's flu vaccine was a good match for the winter's most common flu virus helped make this one of the United States' mildest flu seasons in recent years, health officials say.
There were fewer flu and pneumonia deaths than normally recorded in a typical flu season and fewer than two dozen children's deaths were reported.
As of April 9-15, flu was widespread in only five states: Connecticut, Delaware, Indiana, New York and Rhode Island, the Associated Press reported.
In about half the states in the country, there are now virtually no reports of flu-like illnesses, according to the U.S. Centers for Disease Control and Prevention.
While the mild flu season is good news, health experts are concerned it may lull people into forgetting the danger posed by common flu viruses and a potential flu pandemic that could erupt from the H5N1 bird flu virus currently stalking Africa, Asia and Europe.
"I hope people would not judge what might be coming in the future based on what's happened this year," Dr. Roland Levandowski of the U.S. National Institute of Allergy and Infectious Diseases told AP.
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Bausch & Lomb Alerted About Eye Infections Last Year
U.S. eye-care products maker Bausch & Lomb said Thursday that it was alerted last November about an increase in fungal eye infections among contact lens wearers in Hong Kong.
The company halted shipments of ReNu with MoistureLoc contact lens solution to the Far East in February of this year after it was told about "an unusual spike" in the rate of Fusarium keratitis infections in Singapore, the Associated Press reported.
But Bausch & Lomb had already been informed last November by Hong Kong health officials that they'd seen an increase in hospital admissions due to this kind of infection. However, an investigation by both company and Hong Kong officials found no firm link between the fungal infections and ReNu with MoistureLoc, company spokeswoman Meg Graham said.
On April 10, the company suspended U.S. shipments of its ReNu with MoistureLoc in the United States due to an outbreak of Fusarium keratitis infections among Americans. So far, there have been 186 suspected or confirmed cases in 29 states. The infection can scar the cornea and result in blindness.
While no firm link between the solution and the eye infections has been established, many of the affected U.S. patients used ReNu with MoistureLoc.
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Exercise Reduces Arthritis Joint Pain
People with arthritis who get regular exercise have less joint pain than those who don't get as much exercise, says a poll released Thursday by the Arthritis Foundation.
The survey of more than 2,000 people found that 81 percent of arthritis patients who exercise at least three days a week reported that they have almost no joint pain, compared to 66 percent of those who exercise fewer than two days a week.
"The recommended guideline for people with arthritis is to participate in physical activity three or more days per week, as studies have shown that amount of activity lessens pain and disability," Dr. Patience White, chief public health officer of the Arthritis Foundation, said in a prepared statement.
However, the survey found that, overall, 43 percent of people with arthritis exercise less than three days a week and that 75 percent of those who are inactive are physically limited in some way.
Among arthritis patients 55 and older, 59 percent exercise less than three days a week and 31 percent said that joint pain limits their activities.
"Although the temptation may be to stay inactive in order to avoid aggravating the condition, by being physically active people with arthritis can actually improve their quality of life," White said.
