Schools will begin circulating immunisation consent forms this week before nurses do their rounds next month.
This year, the Boostrix vaccine that protects teenagers against diphtheria, tetanus and whooping cough is being offered to years 7 to 10 students.
In previous years it has been offered only to year 10 students. A spike in cases of whooping cough has prompted the state government to reintroduce free vaccines for expectant mothers and parents of newborns.
In the past 12 months, there has been a 58 per cent rise in known cases, from 2926 in 2013 to 4615 last year.
For the past few years, Whittlesea council has immunised about 75 per cent of year 10 students.
According to a council spokeswoman, misplaced consent forms are largely to blame for the 25 per cent who miss out.
Mayor Ricky Kirkham urged parents to check their teenagers’ school bags for consent cards; it’s as simple as “find it, sign it, return it,” he said.
