COLUMBUS, Ohio (WCMH) — The total number of measles cases in the city of Columbus has now eclipsed 40 after a Tuesday morning update from health officials.

Columbus Public Health said there are now 44 “confirmed and probable” measles cases in central Ohio, a 12-case increase from Monday morning’s update on the CPH dashboard. The cases have been found in 17 daycare and school locations in the area, and increased by five from Monday.

17 people have been hospitalized as a result. All of the 44 cases involved unvaccinated people under 18 years old, according to Columbus Public Health. One case was ruled Monday as “unknown vaccinated status”, but has since been changed to unvaccinated. 57% of the cases are in kids between the ages of 1 and 2.

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

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

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.