Ottawa Public Health is calling 300 families a day, reminding parents to return their immunization consent forms before the start of the school year if they want their children to benefit from vaccines paid for by the province.
Clinics for Grade seven and eight students who want to receive the Hepatitis B, Meningococcal and HPV vaccines begin September 16.
The agency sent out consent forms by mail in June, instead of going through the schools. Less than 50 per cent have been returned.
"We wanted to make sure that everyone has access to them," said Michelle Parks, who works with Ottawa Public Health.
She said even though the vaccines aren't mandatory, they are highly recommended.
"We just want to make sure parents aren't confused by the process and so we've been doing an extra call around," said Parks.
"We suspect that there are actually more forms that have been given in to schools or parents have held on to it thinking 'well I'll bring it in the first day of school,' which is not completely understanding the process," said Parks.
Parks said in past years, between 80 and 90 per cent of students have chosen to be vaccinated.
Children in the Ottawa-Carleton District School board return to school Sept. 3.