Measles, chicken pox, whooping cough...they used to be considered rites of passage for Canadian children.
During the last four decades, with the advent of childhood immunizations, it's been much more rare to see kids coming down with these ailments.
Now New Brunswick is dealing with an outbreak of pertussis, and officials in Quebec are still trying to understand why cases of measles more than doubled last year.
The reasons behind these outbreaks are complicated - like the viruses themselves, but researchers are concerned about the trend among some parents to NOT vaccinate their children.
Host Pauline Dakin speaks with Dr Joanne Langley from the Canadian Centre for Vaccinology.