For years, health officials have been warning that diseases like measles could make a comeback if families stopped vaccinating their children.

Now, they're trying to contain a measles outbreak in Minneapolis that has already sickened six children and appears to be spreading, especially in the Somali community.

This week, health officials confirmed a total of five new cases, three among Somali children who had not been vaccinated because of fears about the vaccine's safety.

Dr. Ruth Lynfield, the state epidemiologist, predicted that more cases will surface.

"Unless we keep the vaccination rate high, we will turn the clock back and have these outbreaks," Lynfield said.

Until this year, only six cases of measles had been reported in Minnesota since 2005.

Since February, six measles cases have surfaced in Minneapolis, all involving children age 4 or younger. Four of the children were hospitalized, and all are now recovering, Lynfield said.

Now, health officials are working with families in the Somali community to try to head off any wider spread.

Dr. Osman Harare, a pediatrician in Minneapolis, said he and another Somali physician are urging parents to get their children immunized.

He said many Somali parents have been afraid of the measles vaccine because of concerns about a possible link to autism. Those same concerns persist among many autism activists around the country, even though they've been debunked by medical experts.

"We need to do some big campaign ... to tell the people the vaccine doesn't have any link with autism," Osman said.

At the same time, the fears have been ingrained in the Somali community because of the rising numbers of children with autism, said Idil Abdul, co-founder of the Somali American Autism Foundation in Minneapolis. "Yes, measles is bad. Nobody wants measles. Nobody wants malaria, and certainly nobody wants autism," she said. The frustration, she said, is that there is no known cause of autism, and "it's not something you want to gamble on." She said public health officials need to take their concerns seriously, while spreading the message about the need for vaccines.

Lynfield said the main concern about the measles outbreak is in the Somali community in Minneapolis because of its low vaccination rates. But she noted that the disease could easily spread to other children in other parts of the Twin Cities who have not been vaccinated.

Investigators believe the outbreak may have begun with a Minneapolis-born child who was infected on a trip to Africa, where the disease is widespread, Lynfield said.

They've been able to connect some of the cases to that one child, who had not been vaccinated. At least five of the confirmed cases involved children who had not been vaccinated, two because they were too young to get the vaccine. State officials say they're still trying to confirm whether the sixth child had been vaccinated.

As part of the investigation, health officials have been tracking down people who may have been exposed to the infected children, and in some cases, asking families to keep their children home for three weeks if they've not been vaccinated. Lynfield said it could take that long for an infected child to show symptoms, which include fever, cough, and a rash that spreads down from the scalp and through the body.

Typically, children get the measles, mumps and rubella (MMR) vaccine at 12 months of age and a booster shot 3 to 5 years later. But Lynfield said that, because of the outbreak, the health department is now recommending that children get the booster shot only four weeks after the first one, to increase their immunity. The recommendation affects families in Hennepin County, and Somali families throughout the metropolitan area.

"Measles vaccine is extremely effective," Lynfield said. "I think we need to remember that we have these very effective tools for a reason, because the diseases can be really severe."

Fifty years ago, more than 441,000 cases of measles were reported in the United States, compared with 140 cases in 2008, according to government statistics.

Worldwide, it is still a dangerous epidemic, affecting 10 million people and killing nearly 200,000 people a year.

"I think the best advice," said Lynfield, "is to be sure that your children are up to date on their measles vaccine."

A Somali community forum on the measles outbreak is being planned March 26 in the Cedar-Riverside neighborhood of Minneapolis.

Maura Lerner • 612-673-7384