Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Climate Change Could Affect U.S. Birth Rate: Study
Climate change may lower the United States' birth rate by making it too hot to have sex, researchers say.
They analyzed decades of data to determine how many babies were born about nine months after really hot days, defined as above 80 degrees. Between 1931 and 2010, every day above that temperature led to 0.4 percent fewer births nine months later, resulting in about 1,165 fewer babies born across the country, CNN reported.
Climate change models predict the number of days above 80 degrees will rise from the current number of about 30 a year to about 90. Over a long time, this could mean about 100,000 fewer births in the U.S. every year, according to the authors of the study published by the National Bureau of Economic Research.
"I wouldn't say it is the end of human civilization, but I would suggest it is going to add to the cost of climate change," lead author Alan Barreca, associate professor of economics at Tulane University, told CNN.
Girl's Cancer Reversed After Breakthrough Gene Therapy
Cancer has been reversed in the first person in the world treated with "designer immune cells," according to U.K. doctors.
Just five months ago, one-year-old Layla Richards had incurable aggressive leukemia. One of her doctors Great Ormond Street Hospital in London said her improvement is "almost a miracle," BBC News reported.
It's too early to know if the pioneering gene therapy cured her, but the case is a major advance in the experimental therapy that had been tested only in mice.
Other gene therapies add new genes to correct a defect, while this approach edits genes inside cells. In this case, immune cells were programmed to find and kill only leukemia cells and to be invisible to the cancer drugs being given to Layla, BBC News reported.
The designer immune cells were then injected back into the girl, who also received a second bone marrow transplant to restore her immune system.
Currently, there is no sign of leukemia in Layla's body, BBC News reported.
The results are the most remarkable thing he's seen in 20 years, according to Dr. Paul Veys, of Great Ormond Street Hospital.
"We're in a wonderful place compared to where we were five months ago, but that doesn't mean cure," he told BBC News.
"The only way we will find out if this is a cure is by waiting that one or two years, but even having got this far from where we were is a major, major step," he added.
The case is being presented at an American Society of Hematology meeting.
"This is the first time human cells, engineered in this particular way, have been given back to a patient and that was a big step for us," Professor Waseem Qasim, of Great Ormond Street Hospital, told BBC News.
"The technology is moving very fast, the ability to target very specific regions of the genome have suddenly become much more efficient and we think that this technology will be the next phase of treatments," he added.
"The technology itself has got enormous potential to correct other conditions where cells are engineered and given back to patients or to provide new properties to cells that allow them to be used in a way we can only imagine at the moment," Qasim explained.
Live Tapeworm Removed From Man's Brain
Doctors removed a live tapeworm from a 26-year-old California man's brain just in time to save his life.
In August, Luis Ortiz developed a severe headache and was rushed to Queen of the Valley Medical Center in Napa, CBS News reported.
A brain scan revealed a tapeworm in his brain and he immediately underwent surgery. Doctors later told Ortiz he would have died within about 30 minutes without the operation.
There were only a few ways the tapeworm could have gotten into his body, doctors informed Ortiz.
"They told me it was uncooked pork or if I went swimming in the river or if I've been to a third world country and I was like, 'I haven't done any of that recently.' But I don't know how long that worm was in my head for," he told CBS News.
Pfizer Boosts Financial Help for Patients
Pfizer Inc. is expanding financial assistance to patients.
In Thursday's announcement, the largest U.S.-based drugmaker said it will double the allowable income level for people to use dozen of its medicines without a copayment, the Associated Press reported.
The move comes as anger grows over rising prescription drug prices in the U.S. and massive price hikes by several smaller drug companies.
Pfizer's approach isn't the best way to make drugs more affordable for everyone, critics say.
"It's not addressing the price of the drug," Clare Krusing, a spokesperson for the trade group America's Health Insurance Plans, told the AP.
"This is the wrong approach when you consider the cost impact that patients have on the back end," because insurers eventually raise patients' monthly premiums to compensate, she explained.
States Must Give Poor People Access to New Hepatitis C Drugs: Federal Government
States cannot legally restrict low-income people's access to groundbreaking hepatitis C drugs, the federal Centers for Medicare and Medicaid Services said in a notice to state Medicaid directors.
The states have a legal obligation to cover prescription medication for the poor, federal officials said, The New York Times reported.
The Obama administration also sent letters to several drug companies, asking what they are doing to make their hepatitis C drugs more affordable.
Hepatitis C affects about 3 million Americans and can eventually destroy the liver. The disease kills more people in the United States than AIDS.
Previous hepatitis C drugs were hit and miss, and many patients experienced intolerable side effects, but newer drugs are highly effective with minimal side effects. However, treatment with the new medicines cost about $100,000, The Times reported.
The high cost is straining government programs and private insurers, and the federal government is concerned that some states are restricting access to the drugs.
New HIV Therapy Approved by FDA
A new treatment for HIV has been approved by the U.S. Food and Drug Administration.
Genvoya -- a tablet containing the drugs elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide -- can be used to treat HIV-1 infection in adults and children 12 and older weighing at least 77 pounds.
The approval is based on four clinical trials that included a total of 3,171 patients. They showed Genvoya was effective in reducing viral loads and comparable to other treatments, the FDA said.
Genvoya -- made by California-based Gilead Sciences Inc. -- contains a new form of tenofovir not previously approved by the FDA. This new form of tenofovir places lower amounts of drug in the bloodstream, but higher amounts within cells where HIV-1 replicates.
"Today's approval of a fixed dose combination containing a new form of tenofovir provides another effective, once daily complete regimen for patients with HIV-1 infection," Dr. Edward Cox, director of the Office of Antimicrobial Products in the FDA's Center for Drug Evaluation and Research, said in an agency news release.
The most common side effect associated with Genvoya is nausea. The product carries a Boxed Warning about the possible risk of a buildup of lactic acid in the blood and severe liver problems, both of which can be fatal.
The warning also states that Genvoya is not approved to treat chronic hepatitis B infection.