DARIEN \u2014 Three town schools reopened Tuesday after all classes and activities were canceled the previous day due to staff shortages related to side effects from the COVID vaccine, the superintendent said. Schools Superintendent Alan Addley said the staff absences were \u201cnearly exclusively attributable to feeling ill after the second vaccination.\u201d Darien teachers and staff members received their second Moderna vaccine on Saturday in a town clinic. In an email to parents Sunday night, Addley said Darien High and Middlesex Middle School would be closed Monday. In an update, officials said Royle Elementary School would also be closed. The day off will be treated as a traditional \u201csnow day,\u201d and will be made up at the end of the academic year. Some social media comments in reaction to the school closures criticized the teachers and accused the Darien teachers union of coordinating the absences. Joslyn Delancey, president of the Darien teachers union, called the criticism \u201cdisheartening.\u201d \u201cI'm at school today after a pretty miserable reaction to the vaccine over the weekend. Some comments indicate that the union organized teachers calling out,\u201d Delancey, a fifth-grade teacher at Tokeneke School, said Monday. \u201cThe union president is at work and teaching today and encouraged teachers to rally if they could and come in to teach. The only reason a teacher would have called out is because s\/he was still feeling the severe reactions to the vaccine,\u201d Delancey said. Delancey pointed out that other Connecticut school districts have experienced the same issue. \u201cTeachers got vaccinated to make sure that schools were safer. Darien teachers are committed to doing the very best for their students and have ensured that we have had the most in-person teaching as possible,\u201d she said. Addley called the criticisms \u201cunfortunate and disappointing.\u201d A spokesman for the state Department of Education said Monday steps are being taken to help avoid the sudden school closures that have occurred due to large numbers of teachers calling out sick with side effects from the COVID vaccine. Peter Yazbak, a spokesman for the state Department of Education, said school districts are trying to avoid these disruptions through creative scheduling. \u201cI can confirm that a few districts have closed individual schools as a result of (side effects from the vaccine),\u201d Yazbak said. \u201cHowever, our department has also issued guidance for districts to communicate frequently with school staff, students and families the importance of staying out of school when they feel sick, when they are awaiting a test result, or when they are in an isolation or quarantine period.\u201d Darien\u2019s spring break begins April 12. Addley said the district is discussing whether to consider guidelines from the Centers for Disease Control and Prevention regarding spring break travel.