A 48-year-old government schoolteacher, who had tested positive for COVID-19, died at a private hospital here on Saturday, following which her 12 colleagues and three students also returned positive results, an official said.
Schools in the State reopened for Classes 5 to 12 from January 7 after a government order.
The deceased teacher taught maths at the Government Senior Secondary School Galib Kalan in Jagraon.
Additional Deputy Commissioner Neeru Katyal said the school has now been shut and the samples of other students and the staff were being taken for testing.
State Education Minister Vijay Inder Singla had said the decision to open schools was taken following a persistent demand by parents.