COLUMBUS, Ohio (WCMH) — An outbreak of measles among children has temporarily closed a Columbus childcare facility.

Columbus Public Health and Franklin County Public Health are investigating a measles outbreak tied to one unspecified childcare facility in the city, the agencies announced Wednesday. As of Wednesday, there are four confirmed cases of measles tied to the facility, all in unvaccinated children with no travel history.

“We are working diligently with the cases to identify any potential exposures and to notify people who were exposed,” Columbus Public Health Commissioner Dr. Mysheika Roberts said in a press release.

At a city meeting Wednesday, Roberts said all infected children are under the age of 4, with one requiring hospitalization. The childcare location will remain closed for 21 days, Roberts said. NBC4 has reached out to the agencies regarding which facility was impacted.

Roberts encouraged those unvaccinated against measles to get the measles-mumps-rubella vaccine. The two-dose MMR vaccine is 97% effective against the measles virus, according to the Centers for Disease Control and Prevention.

The outbreak has doubled Franklin County’s confirmed measles cases to eight since June 2022, according to Franklin County Public Health. In light of the cases, both agencies encouraged parents to ensure their children’s immunizations are up to date.

Measles is a highly contagious virus transmitted through coughing and sneezing. According to the CDC, infected individuals can spread the virus up to four days before becoming symptomatic.

The virus is commonly identified through its hallmark rash, a network of flat red spots that might start at the hairline and spread downward across a person’s body. But by the time the rash occurs, a person has already been contagious for several days. Other symptoms both agencies urged people to look out for include a high fever, runny nose and watery eyes.

It typically takes 8 to 12 days after exposure for symptoms to develop, according to both public health agencies.

Measles is one of 14 diseases the Ohio Department of Health requires immunization against for all children attending childcare, Head Start or Pre-School programs. Children are exempt from immunization requirements for three reasons: The child has a health condition making immunization dangerous, immunization is not medically appropriate for the child’s age, or a child’s parent or guardian has an objection of conscience or religious conviction against immunization.

The CDC recommends all children receive two doses of the MMR vaccine, with the first between 12 and 15 months old and the second at 4 through 6 years of age or at least 28 days after the first dose.