VANCOUVER -- Three recent COVID-19 exposures in Surrey schools have been confirmed to involve one of the variants of concern that health officials around the world have been monitoring.

Recent exposures at École Woodward Hill Elementary School, Tamanawis Secondary School, and A.H.P. Matthew Elementary School involved the B.1.1.7 variant of the coronavirus that causes COVID-19, the Surrey school district confirmed in letters to each school's community on Saturday.

Surrey schools Supt. Jordan Tinney tweeted an image of the letters Saturday afternoon, along with his thanks to Fraser Health and to the staff, students and community at each school.

The B.1.1.7 variant first emerged in the United Kingdom and is more easily transmitted than other types of the virus.

The exposures at the schools in question happened from late January to mid February, and the letters acknowledge that the school district only learned on Saturday that the strain of the virus that was in the schools was the U.K. variant.

"Testing for the variant takes longer than standard COVID-19 testing, which is why we have received this information now," each letter says.

The exposures at A.H.P Matthew happened on Jan. 26, 27 and 29, according to the letter to that school's community.

The exposures at Tamanawis Secondary happened from Jan. 26 to Feb. 8, and the exposures at Woodward Hill happened from Feb. 3 to 5 and from Feb. 8 to 12.

Fraser Health has contacted more than two dozen people at the three schools and instructed them to self-isolate and get tested for COVID-19, according to the letters.

Most of those people are associated with École Woodward Hill Elementary, where "two classes and over 20 individuals" have been instructed to stay home and get tested.

The health authority has contacted three people at A.H.P. Matthew and three at Tamanawis with the same instructions.

As of Friday, B.C. had confirmed 72 cases of COVID-19 "variants of concern." Most of those (52) were the U.K. variant, while the other 20 were B.1.351, a variant first noted in South Africa. 

B.C. has also detected one case of the variant B.1.525, which is associated with Nigeria. The province's single case is in a person who had recently returned from that country to B.C.'s Interior.

In January, the province tested more than 80 people associated with Garibaldi High School in Maple Ridge after a person who was a close contact of someone with a known case of the U.K. variant spent time at the school. All of the tests came back negative.  

Canada's chief public health officer Dr. Theresa Tam has cautioned that the more-contagious variants currently spreading in all provinces could lead to a seven-fold increase in the number of new cases detected across the country each day.