What's the difference between COVID-19, RSV and influenza?

Cases of respiratory infections are on the rise across Canada as the country faces what health officials are calling the "triple-threat" of COVID-19, influenza and respiratory syncytial virus (RSV).

According to the Public Health Agency of Canada, the latest respiratory virus monitoring report showed that the test positivity-rate for when it came to detecting influenza A was 6.44 per cent for the week of Oct. 29, compared to 2.66 per cent in the previous week. The test positivity rate for RSV was 7.0 per cent across Canada, up from 4.74 per cent in the previous week.

The uptick in infections has also led to hospital capacity becoming strained, especially at pediatric hospitals. In Ontario, hospitals are even being asked to admit teenage patients to adult intensive care units.

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Meanwhile, pharmacies across Canada are also dealing with a shortage of cough syrup and cold medicine, particularly medication for children.

Here's how the three infections vary and what parents need to know during this viral wave.

WHAT ARE THE SYMPTOMS?

It can be difficult to tell whether your child has gotten COVID-19, RSV or the flu, as the three share many of the same symptoms.

"These are respiratory viruses, all three of them, that are transmitted in very similar ways and are prevented in terms of preventing their transmission in in very similar ways," Dr. Brian Conway, medical director of the Vancouver Infectious Diseases Centre, told CTVNews.ca over the phone on Thursday.

"All of these diseases could potentially lead to hospitalizations. All of these have can have a significant morbidity and mortality, with COVID leading the way, followed by RSV, followed by influenza," he added.

According to Health Canada, influenza symptoms typically appear between one and four days after exposure, usually in the form of a fever, coughing and muscle aches or pain. Other common symptoms can include headache, chills, tiredness, loss of appetite, sore throat and runny nose. For children, symptoms may also include diarrhea, nausea and vomiting.

RSV symptoms also include runny nose, sneezing, coughing, sore throat, fatigue and fever, Health Canada says, and children and immunocompromised individuals are at the highest risk. The U.S. Centers for Disease Control and Prevention says symptoms typically show up within four to six days after becoming infected. In very young infants, RSV symptoms may include irritability, decreased activity and breathing difficulties, the CDC says.

For COVID-19, Health Canada's list of symptoms include sore throat, runny nose, sneezing, a new or worsening cough, shortness of breath, fever, chills, fatigue, muscle aches, loss of smell or taste, headache, abdominal pain, diarrhea and vomiting.

The incubation period for the SARS-CoV-2 virus is typically much longer than RSV or the flu virus. Symptoms generally appear within three to seven days after exposure, but it may take as long as 14 days.

Conway notes that it may be difficult to pinpoint specific symptoms in children. Health Canada recommends talking to a health-care provider if parents notice their children being irritable, not eating or drinking as usual or not waking up and interacting with others.

"In children, obviously the symptoms are often not as specific because children aren't able to tell us what's wrong in as much detail as adults and they just generally feel very unwell," he said.

PREVENTING INFECTIONS

Doctors and health officials agree that the best way to prevent COVID-19 and influenza infections is to get vaccinated, especially now that both the bivalent COVID-19 vaccine and the flu vaccine are widely available across Canada.

"The vaccine for influenza, what's circulating right now, seems to be a very good match to the vaccine. So we do anticipate it having a strong protective effect against the need to be hospitalized," Dr. Kieran Moore, chief medical officer of Ontario, told CP24 on Wednesday.

The flu vaccine is available for children as young as six months of age. The new bivalent vaccines are only available for individuals 12 and over, although monovalent booster vaccines are still available for anyone six months of age and older.

Currently, there's no vaccine available for RSV, although Pfizer says its clinical trial for a new RSV vaccine shows positive results. Since RSV mainly spreads through droplets and can survive on surfaces for several hours, Conway says regular hand washing can still go a long way.

"We do really need to keep washing our hands the way we've learned to do in the past two years. I think that's helped us a lot. And I think that daycares, schools and so on should have hand sanitizer available and that it should be part of our normal," he said.

While mask mandates have almost entirely disappeared across Canada, choosing to wear a mask can also help prevent the transmission of any respiratory infectious disease. Some experts, such as the former head of Ontario's COVID-19 science advisory table, have even called for the return of mask mandates in public spaces.

If your child does end up becoming sick with RSV, COVID-19 or the flu, experts agree that they should stay home until they feel better. Conway also recommends keeping a mask on in public for the next few days after recovering.

"I'm very much of a proponent of wearing a mask for several days after you reintegrate your usual daily activities," he said. "I think that's probably a good idea because there may be some residual transmission."

With files from CP24