(AP) — A government study offers a new theory on why the whooping cough vaccine doesn’t seem to be working as well as expected.

Researchers concluded that while the shot may keep people from getting sick, it doesn’t prevent them from spreading the germ.

Whooping cough is a highly contagious disease most dangerous to children. Last year was the nation’s worst year for whooping cough in six decades. Some studies have suggested that a newer version of the vaccine doesn’t last as long as the old one.

The new research tested the vaccine in baboons. They didn’t get sick but still may have been contagious for five weeks.

The study was published Monday in the journal Proceedings of the National Academy of Sciences.

(AP) — A Lincoln firefighter’s house has been damaged by a chimney fire.

Battalion Chief Dennis Clark says the firefighter had trouble with smoke not venting from a fire he’d built in his fireplace on Saturday. He put out the fire in the fireplace but heard crackling behind a chimney wall. The firefighter called 911 a little after 2 p.m., and his colleagues soon arrived to put out the blaze.

Damage was estimated at $20,000.

(AP) — A Grand Island man has been treated for smoke inhalation after a fire that engulfed a shed and damaged nearby mobile homes.

Grand Island Fire Capt. Brad Laub says the fire broke out in the shed a little before noon on Sunday and soon spread to one of the mobile homes, a pickup and another shed. Siding melted on another mobile home.

Laub says the man was taken to St. Francis Medical Center.

Investigators suspect an electrical malfunction caused the fire.

(AP) — The death of a 30-year-old woman whose body was found in a York apartment has been ruled accidental.

The body of Cassandra Carmody was found on Oct. 30.

York County Attorney Candace Dick said Friday that autopsy tests showed Carmody died because a combination of four medications she took had a toxic effect on Carmody and stopped her breathing.

Dick says there is no evidence that Carmody intended to harm herself. York Police Chief Don Klug has said there were no indications that any crime was involved in Carmody’s death.

(AP) — Iowa’s governor and congressional delegation are trying to shore up political support for ethanol, which is slipping as the nation produces more of its own oil.

Gov. Terry Branstad is pushing to reverse the Obama administration’s proposal to cut the required amount of ethanol in the nation’s fuel supply. Almost half of Iowa’s corn crop goes to manufacture the grain alcohol, which is blended into gasoline.

Presidential candidates traditionally supported the federal mandate when they campaigned in Iowa, but many now say it is no longer justified. Environmentalists have complained about impact of expanded corn production. But Branstad says the federal mandate is important to Iowa farmers with corn prices low.

(AP) — A Lincoln woman continued recovering at a hospital Sunday from 13 stab wounds a day after police arrested her estranged husband.

Lincoln Police said the woman was wounded shortly after 3 a.m. Saturday at an apartment in northeast Lincoln.

Officers responding to the assault found blood but not victim because the woman had gotten herself to the hospital. Her name is not being released.

Police said the woman identified her estranged husband as her attacker. The woman had a protection order against him.

Police arrested 31-year-old Robert Haggan later Saturday. He remained in custody Sunday facing several charges, including attempted murder and using a weapon to commit a felony.

(AP) — Nebraska authorities are investigating a rollover crash that killed a 20-year-old woman over the weekend.

The crash happened in Thurston County early Saturday morning.

The Nebraska State Patrol says Princess Morris of Macy died in the crash. She was a passenger in a Chevrolet pickup truck driven by 20-year-old Miguel Tapia of Walthill.

The crash happened northwest of Walthill after Tapia lost control of the truck and over corrected.

Neither Tapia nor Morris wore seat belts. Authorities say Tapia was unhurt.

(AP) — Construction on the Pawnee Plunge Water Park expansion in Columbus won’t begin before the spring of 2014, months behind schedule.

The city’s public property director, Doug Moore, broke the news to the Columbus Board of Parks Commissioners on Tuesday.

The Columbus City Council awarded $330,600 in April for design and construction management services on the project.

A preliminary plan that includes the addition of a swimming pool, diving area, rock climbing wall, ship-themed play structure and other features was approved in July.

At that time, city officials hoped to have the project completed before the water park opens in May 2014. However, Moore said last month he could only guarantee it would be done before 2015.

The water park will remain open during construction.