A previous report on Tuesday’s increase in measles cases can be seen in the video player above.

COLUMBUS, Ohio (WCMH) — Officials with Columbus Public Health have confirmed another three measles cases in central Ohio, increasing the total to 18.

Officials confirmed an extra two daycare centers and one school in the area have had measles cases reported. CPH did not specify which daycares or school it learned had cases, or how many at each.

On Tuesday, health authorities reported that 15 children were infected with measles from five daycare centers in and around Columbus. Last week, the first four measles cases were confirmed from an unspecified childcare center in the city.

A high majority of the 18 confirmed cases are in young children, per CPH. Every single one of the 18 confirmed cases are in people who are unvaccinated. At least seven of those children have been hospitalized.

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.

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.