Fall sniffles and coughs signify cold viruses are circulating again, health experts say

"This is the calm before the storm," Dr. Peter Lin, medical columnist for CBC Radio, told CBC Kitchener-Waterloo's Craig Norris on The Morning Edition .

"The kids start mingling at school and the virus exchange program has now begun."

Children can be in close proximity to one another inside their classroom which makes it easy for these viruses to spread, he said. Coughing, sneezing and breathing near one another is one of the main ways a virus can spread.

"Viruses can't move on their own, they don't fly, they don't crawl because they know that we will move them around for them. So I breathe out the virus and you suck them in. So we are the Uber delivery service for them," Lin said.