Health officials have asked students and staff potentially exposed to the virus and who either have not been vaccinated or cannot verify immunity to stay home.

There are now more cases of measles in America than in any year since the disease was eradicated nearly 20 years ago.

So far this year, 465 infections have been reported, with numbers approaching their highest since measles returned to the country.

Most people who contracted the disease were unvaccinated and some state legislatures are now considering whether to curtail nonmedical vaccine exemptions.

The World Health Organization reports that a number of countries are experiencing “sizeable” numbers of the infection due to a failure to vaccinate.

The outbreak has infected 50,000 people and killed 300, most of them children, since cases began to crop up in October 2018.

Most of the 34 patients are under 10 years old, and almost all have been confirmed as unvaccinated against the virus.

In one county alone, more than 100 cases have been confirmed since October.

The WHO reports more than 41,000 cases in the region in the first half of 2018.