The All India Institute of Medical Sciences (AIIMS) is learnt to have started screening of children aged 6-12 years for the clinical trials of India's first indigenously developed Covid-19 vaccine, Bharat Biotech's Covaxin.Sources said that the recruitment and clinical trials of the children aged 6-12 years will start from Tuesday. The trial on children aged 6-12 has already started at AIIMS Patna.Participants would be given the vaccine after their screening report comes. The trial would ensure if the Bharat Biotech jab is suitable for children.Delhi AIIMS has decided to start the trial drive after the recruitment and clinical trial for single-dose Covaxin for 12-18 age group is over.After the recruitment of 6-12 year-old children, AIIMS Delhi will be conducting trials for the age group 2-6 years of children. The trials are taking place at 525 centres.The screening of children for the trial of single-dose Covaxin among those aged between 2 and 18 years started at the AIIMS in New Delhi on June 7 after India's drug regulator had granted permission for conducting the Phase 2 and 3 clinical trials of Covaxin in the age group 2 to 18 years on May 12.AIIMS Patna, Mysore Medical College and Research Institute in Karnataka have also been selected to conduct clinical trials on children.Covaxin is being used on adults in India's ongoing Covid-19 vaccination drive since January 16 this year. The government last week cautioned that even though Covid-19 has not taken a serious shape among children till now, its impact can increase among them if there is a change in virus behaviour or epidemiology dynamics, and said preparations are being strengthened to deal with any such situation.A national expert group has been formed to review Covid-19 infections in children and approach the pandemic in a renewed way to strengthen the nation's preparedness, NITI Aayog Member (Health) V.K. Paul had said at a press conference."The group has examined signs which were not available four-five months before."