CONCORD, N.H. (AP) — New Hampshire's new vaccine registration system struggled to meet initial demand in its first big test Monday though the pace later picked up, and officials expected more than 100,000 new signups by day's end.

The state last week replaced the federal Vaccine Administration Management System with its own Vaccine and Immunization Network Interface, VINI for short. Thousands of people experienced problems with the previous system, particularly in scheduling their second doses, and officials had expected the new system to avoid those woes. But it was temporarily beset with technical problems Monday morning, when registration opened to anyone age 50 and older.

In a notice on state's vaccine website early Monday morning, officials apologized for the issues and said they would be addressed as soon as possible. By late morning, the message described delays due to unprecedented volume, and urged viewers to try again 10 minutes later if they weren't successful.

Gov. Chris Sununu said 75,000 people had booked appointments by 5 p.m., and registrations were being processed at a quicker pace.

“An unprecedented volume of web traffic was experienced this morning, a good sign that Granite Staters are ready and eager to receive their vaccine, which did cause some to experience delays,” he said in a statement.

Sununu last week said about 200,000 first-dose appointments would be loaded into the system.

"So folks shouldn’t worry about having to be just the first one in line. There’s going to be plenty of room for everyone," he said Thursday.

In other coronavirus developments:

___

VACCINATED TEACHERS

Schools in multiple communities were closed Monday because of staff absences attributed to vaccine side-effects.

Teachers, school staff and child care workers became eligible for the vaccine last week, and a vaccination clinics were held in numerous locations over the weekend.

School was canceled Monday in Concord because of staff reactions to vaccines, said Assistant Superintendent Donna Palley. A similar situation was reported in Hopkinton and in the Hillsboro-Deering district.

“A large number of staff members received their COVID vaccines yesterday and many are reporting feeling very ill. There will be no remote or in-person learning for the high school today,” according to a message on the Hillsboro-Deering district website.

The main side effects from the COVID-19 vaccines currently approved in the U.S. include pain at the injection site and flu-like fever, fatigue and headache.

___

THE NUMBERS

More than 77,000 people have tested positive for the virus in New Hampshire, including 207 cases announced Monday. The number of deaths stood at 2,334 with none reported Monday.

The seven-day rolling average of daily new cases in New Hampshire has risen over the past two weeks from 205 new cases per day on March 6 to 275 new cases per day on Saturday.