Hamiltonians who haven't fallen prey to this year's aggressive strain of seasonal flu may want to stock up on cough syrup just in case, as reported cases of influenza are already up over previous years. 

'Last week we saw more than double the confirmed cases of flu than what we'd seen in any given week in the past five years.'    —Jordan Walker, Hamilton Public Health Services

"Last week we saw more than double the confirmed cases of flu than what we'd seen in any given week in the past five years," Jordan Walker, manager of infectious diseases for Hamilton Public Health Services, told CBC Hamilton. 

Hamilton's first official case of seasonal flu was reported on Nov. 9. Since then, and within the reporting period of Nov. 1 to Jan. 3, there have been 236 lab-confirmed cases of flu, said Walker, the majority of which are Influenza A.

While Walker was hesitant to speculate about what the spike in numbers may portend going forward, he did acknowledge that this year has been a highly active flu season.

'January even worse for flu than December'

Some are predicting that the already active influenza season is about to get a lot more so this month.

Google Flu Trends is forecasting that January may be even worse when it comes to flu than December. It uses an algorithm that blends publicly reported cases of flu with the number of flu-related search terms people input online to come up with its trend report.

"Flu activity on Google is going up since mid-December and historically that [increase in flu-related Google searchers] indicates that more people are sick," said Google spokesperson Aaron Brindle.

While January's flu cases remain to be counted, December was a particularly brutal month for flu cases in Ontario.

In December, 1,448 cases were reported during the last two weeks of December, according to Public Health Ontario. That number accounts for 53.4 per cent of the 2,712 cases reported thus far this year.

'How to reduce your risk of catching the flu'

While there's no foolproof way to avoid getting ill, Walker said that the most effective form of protection is getting the flu vaccine. The city of Hamilton is no longer running its free flu clinics, but people can still get vaccinated at many walk-in clinics, by their family doctor and at many local pharmacies, he said.

Frequent hand washing is another way to mitigate your risk of infection.

Walker also advises people to stay home from work when they're sick and to cover their mouths when they cough to avoid infecting others.

'Flu: stats, signs and symptoms'

Over the course of a normal flu season, one in 10 adults and one in three children will come down with the flu, according to Health Canada.

There are two main kinds of flu viruses: influenza A, which can make you really sick, and B, which is usually milder.

Influenza is a highly contagious respiratory disease that strikes as many as eight million people in an averfage flu season, usually between October and April. While flu and cold symptoms can be similar, influenza is much more serious because it drastically reduces the body's ability to fight off other infections.

A cold and the flu share some of the same symptoms. But even a bad cold is pretty mild, compared to a bout with the flu. No pill or herb will get rid of either — each is caused by viruses, and antibiotics, herbal remedies and homeopathic medicines are useless against them. You can take things that might ease your symptoms, but there is no cure. Your illness will have to run its course.

A cold usually comes on gradually —over the course of a day or two. Generally, it leaves you feeling tired, sneezing, coughing and plagued by a running nose. You often don't have a fever, but when you do, it's only slightly higher than normal.

Flu, on the other hand, comes on suddenly and hits hard. You will feel weak and tired and you could run a fever as high as 40 degrees Celsius. Your muscles and joints will probably ache, you will feel chilled and could have a severe headache and sore throat. Getting off the couch or out of bed will be a chore. The fever may last three to five days, but you could feel weak and tired for two to three weeks.

With files from CBC News