Bengaluru, Nov 30 : A 'high alert' has been sounded in Tumakuru district of Karnataka on Tuesday after 15 students from Kerala studying nursing course tested positive for Covid-19 there, officials said. All the 15 individuals have been housed at a quarantine centre and their swab samples sent to Bengaluru for further tests, District Commissioner Y.S. Patil said. The students belonged to Siddaganga, and Vadiraj nursing institutes in Tumakuru. The increasing number of clusters in the state have become a cause of worry for the Health Department. The state government has initiated stringent measures along the border areas of Kerala and Maharashtra to contain the spread of the virus. Health Minister K. Sudhakar has chaired a high-level meeting on Tuesday to chalk out the measures following the emerging situation in the backdrop of the detection of Omicron -- the new Covid variant. Meanwhile, Patil said it has been made compulsory for students above the age of 18 to take the vaccine jab. Students will have to take at least one dose to enter the class. A circular has also been issued in this regard. More than 280 cases of Covid were also reported in Dharwad medical college. The authorities, however, have heaved a sigh of relief as the infection did not spread out of the campus in the residential areas. /IANS