The winter ‘quademic’? You may be sick with one of these 4 viruses – National
Sneezing, fever, chills, vomiting, coughing — it’s not just one virus wreaking havoc this winter; it’s a combination of four major illnesses: influenza, respiratory syncytial virus (RSV), COVID 19 and norovirus.
In the United States, some health experts are referring to the simultaneous spread of these four viruses as a “quademic.”
But is the same spread happening in Canada?
“I think we are experiencing something very similar,” said Matthew Miller, the director of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University in Hamilton, Ont.
“Our low COVID levels are still as high as many of the other viruses which are, nearing peak. For RSV it looks like we’ve reached that peak already, and for influenza A, cases are still shooting up,” he told Global News.
While cases of these three respiratory illnesses are high in Canada, there’s another virus on the rise as well: norovirus, also known as the stomach bug.
Influenza, RSV and COVID-19 are primarily spread through respiratory droplets, while norovirus is mainly transmitted through contaminated surfaces and is so resilient it can even survive hand sanitizer, Miller said.
And during the colder winter months, as people spend more time indoors in close proximity, the risk of spreading all four viruses increases, creating the perfect conditions for a surge in infections.
“Certainly these months are the usual peak of what we would call respiratory virus season and it happens for a variety of reasons. One is that the weather conditions in the winter favour the viruses’ ability to transmit. So the coldness and the relative lack of humidity help the virus sort of live longer on surfaces and transmit better in the air,” Miller explained.
“In addition, the forced air heating in our houses also tends to dry out our nose and throat, what we call our mucosal membranes. And that wetness and stickiness that lines our nose and throat is actually our first line of defence against bugs. It keeps a protective layer between viruses and our cells.”
When our noses dry out, especially at night while we’re sleeping, it becomes easier for viruses to enter our body, he added.
Here’s a look at the four big viruses circulating in Canada.
Influenza, commonly known as the flu, is a highly contagious viral infection that affects the respiratory system, including the nose, throat and lungs. It is caused primarily by the influenza viruses, A and B, according to Health Canada.
Symptoms include fever, cough, chills, fatigue, headache, sore throat, loss of appetite and nasal congestion.
The latest data from the Public Health Agency of Canada (PHAC), covering the week of Jan. 18 to Jan. 24, shows influenza numbers are on the rise. There were a total of 5,162 detections of influenza from 37,997 tests, representing a percent positivity of 13.6 per cent from that week, PHAC said.
Despite the rise in cases, the number of confirmed influenza outbreaks has remained “generally stable” over the past three weeks, PHAC added.
Get weekly health news
Receive the latest medical news and health information delivered to you every Sunday.
Among the reported cases, people aged 65 and older accounted for the highest proportion of weekly detections.
RSV is a common respiratory virus that affects the lungs and airways. It’s especially known for causing infections in young kids, older adults and people with weak immune systems, Health Canada said.
For most healthy people, RSV may just show mild, cold-like symptoms, but it can lead to more serious breathing problems for those in higher-risk groups.
Symptoms in mild cases include a runny nose, coughing, sneezing, mild fever and a sore throat. In more severe cases, it can cause wheezing, rapid breathing, shortness of breath and bluish colour around the lips or fingers.
The latest data from PHAC, covering the week of Jan. 18 to Jan. 24, shows there were a total of 3,040 detections of RSV from 35,016 tests, representing a percent positivity of 8.7 per cent.
People aged 65 to 84 years reported the highest proportion of weekly detections.
The overall rate of RSV cases is stabilizing, PHAC added.
COVID-19 is another respiratory illness, but it’s caused by the SARS-CoV-2 virus. The COVID-19 strain that is dominating in Canada this winter season is K.P3, a sub-lineage of the omicron strain.
Symptoms typically include fever, cough, fatigue, loss of taste or smell, sore throat, headache, muscle pain, vomiting and congestion or a runny nose, according to PHAC.
The latest data from PHAC, covering the week of Jan. 18 to Jan. 24, shows the percentage of tests positive for COVID-19 decreased by 8.3 per cent.
“The number of test-confirmed outbreaks associated with COVID-19 reported by participating provinces and territories has been generally decreasing over the past four weeks,” PHAC stated.
Norovirus is a highly contagious virus that causes gastroenteritis, an inflammation of the stomach and intestines. It’s often referred to as the stomach flu, though it’s not related to the flu.
Symptoms include nausea, vomiting, diarrhea, stomach cramps, fatigue, a low-grade fever, chills and a headache.
Unlike COVID-19, influenza and RSV, Canada does not release weekly reporting numbers for norovirus.
“Unfortunately, in Canada, we don’t have real-time public reporting, but certainly there have been lots and lots of reports of viral gastroenteritis over the last several weeks. So we’re experiencing high numbers of those as well,” Miller said.
“The virus is usually a very nasty 24-hour bug. They rip through classrooms and workplaces and households, and put a lot of stress on the plumbing systems, but largely do not cause a lot of hospital admissions.”
However, Miller emphasized that the primary concern with norovirus is dehydration, making it especially important to stay well-hydrated.
Last month, preliminary data from PHAC showed that norovirus infections are being reported nationwide at rates higher than the five-year average from 2019 to 2023.
And an Ontario public health official recently confirmed that norovirus was detected in a group of 190 people at the University of Guelph who reported symptoms of gastroenteritis over the past week.
Can you tell which virus you have?
With COVID-19, people got used to reliable at-home tests that could quickly confirm if they were infected, Miller said.
But the reality, he said, is that for most people, diagnostic tests for common respiratory infections are rarely used because the results often don’t lead to any specific medical action (such as staying home and getting plenty of liquids and sleep).
“Viruses like RSV, influenza and COVID-19 normally present with at least some type of respiratory symptom, like coughing, sneezing, runny nose alongside things like fever or chills or tiredness,” he explained.
“Those are almost impossible for the average person to distinguish from one another. But things like COVID and especially influenza, tend to cause more severe symptoms of fever and chills and lethargy than what we would consider the common cold,” he said.
Although respiratory infections can be difficult to differentiate, norovirus is often a bit clearer.
“For norovirus, the big differentiator is that it is characterized almost always by very severe gastrointestinal symptoms. So very severe acute diarrhea, nausea, sometimes vomiting. Those symptoms are less common with the respiratory viruses,” Miller said.
When it comes to treating these viruses, he recommended using over-the-counter remedies to manage symptoms and discomfort, while also getting plenty of rest and staying hydrated.
“If you get severely ill, obviously it’s important to seek medical care,” he added.
Miller emphasized that the best protection against these viruses is vaccination.
The influenza vaccine is still available, even at this time of year, so it’s not too late to get it. Additionally, there’s the COVID-19 vaccine, an RSV vaccine for older adults and expectant mothers, and an antibody treatment for newborns to protect against RSV.
While there is currently no vaccine for norovirus, one could soon be on the way.
The American pharmaceutical company Moderna is developing an mRNA-based vaccine for norovirus and plans to submit a marketing application to U.S. health regulators in 2026.
Miller also stressed that proper handwashing and staying at home when you’re sick are important defences against viruses.
While hand sanitizer works well against the spread of influenza and COVID-19, Miller warned that norovirus is exceptionally infectious and can persist in the environment.
Unfortunately, hand sanitizer is ineffective at killing it.
“The virus that causes norovirus spreads on surfaces and it can stay there for a very long time. Hand sanitizer is nearly useless for norovirus. So conventional hand washing is much better,” he said.
“Handwashing is meant to actually remove the virus from your hand. And so hand-washing when available should always be preferred over hand sanitizer.”
