The Indiana Department of Health on Wednesday confirmed five additional cases of the highly infectious measles virus — less than 48 hours after announcing the state’s first laboratory-confirmed case this year in an unvaccinated Allen County minor.

Because measles is so easily spread, a single case is considered an outbreak.

The newly reported cases include three more minors — also unvaccinated. The vaccination status of two infected adults is “unclear,” according to a news release.

“All six cases are connected to each other but at this time there are no known links to outbreaks in other states,” the department continued.

“State and local public health officials are working together on the investigation to contact those with known exposure to help prevent further spread of infection,” the news release added. It said the risk to the general public “remains low.”

Thomas Duszynski, an epidemiology expert at Indiana University Indianapolis’ School of Public Health, said the risk is “low, but it’s not zero.”

“Measles is one of the most infectious organisms on the planet,” he told the Capital Chronicle. A single person with measles passes the virus on to an average of 12-18 people.

If those involved in the outbreak are quarantining, the risk to fellow Hoosiers is lower, Duszynski said. But measles symptoms can also take up to 21 days to present, meaning that infected people can spread the virus before realizing they’re sick.

Symptoms typically include a fever, cough, white bumps inside the mouth and a rash that begins at the hairline and extends down the torso and limbs. The department encouraged Hoosiers experiencing symptoms to stay home and call their doctors “right away,” before going to the doctor’s office. Those with the virus should stay home and away from others.

The risk of severe disease is higher in those with immature or compromised immune systems: young children, pregnant women, the elderly and the sick.

“The current outbreak that’s going on in the U.S., 70-plus of the 600-plus cases have been hospitalized, and most of those are children under the age of five,” he said.

Duszynski warned that measles can also lead to life-threatening complications like pneumonia and brain swelling. Texas health officials have confirmed two measles deaths in unvaccinated school-aged children.

Because it’s a virus, he said, “There is no treatment for measles. There’s only supportive care.”

However, the measles vaccine is among the most effective around. IDOH said one dose of the measles, mumps and rubella vaccine provides 93% protection, and the full two-dose course provides 97% protection.

Children are routinely vaccinated for measles at 12-15 months old, and again at 4-6 years of age before they go to kindergarten. But children as young as 6 months old can receive the measles vaccine if they are at greater risk.

IDOH encouraged residents to check with their health providers and ensure they and their families are up to date with their vaccines.

Duszynski said people born before 1957 are considered immune “because measles was so common prior to that, that almost everybody got measles. And if you were lucky enough to survive, you have lifelong immunity.”

But those born 1957-1968 may want to consider a booster. A small percentage of the vaccines given over that time period were of the killed virus — less effective than the live virus vaccine typically used. Those with just one dose may also consider a second.

Duszynski noted that 95% of the population must be vaccinated to secure “herd immunity,” protecting people who cannot get the vaccine, like babies, pregnant women and people allergic to its ingredients.

He recommended that people hesitant to get the immunization talk to their doctors.