Respiratory Viruses 101: Explore the differences between respiratory viruses and how to better manage the symptoms

What is a respiratory infection?

A respiratory infection is when a microbe causes an infection in the respiratory system. If the infection only affects the structures in the head (such as the nose, throat, sinuses, and pharynx), it is called an upper respiratory tract infection. If the infection affects the lungs, it is called a lower respiratory tract infection (such as pneumonia).

These respiratory infections are most often caused by a virus, such as one of the many rhinoviruses (common cold), influenza (flu), SARS-CoV-2 (COVID-19), or respiratory syncytial virus (RSV).

More rarely, bacteria may be the primary cause of infection (e.g., in some streptococcal pharyngitis). A bacterial infection can also develop in addition to the initial viral infection. This is called bacterial superinfection.

Finally, yeast (microscopic fungi) can cause serious respiratory infections in people with weakened immune systems.

How can I tell the difference between influenza, COVID-19, and RSV?

Influenza, COVID-19, and RSV can cause very similar symptoms. For this reason, the symptoms of these three infections are often grouped together under the term "flu-like syndrome." 

Typical symptoms include

• Chills or fever
• Cough, often of sudden onset
• Fatigue, often severe
• Muscle or joint aches
• Headache
• Sore throat

These infections usually last from 14 to 21 days but can last longer.

Influenza always causes significant symptoms, while COVID-19 and RSV can sometimes cause milder infections with cold-like symptoms. 

For otherwise healthy people, it is usually not necessary to know exactly which virus is causing the infection, as this will not change the treatment. Mild to moderate symptoms can be treated at home.

However, for people at risk of complications such as severe pneumonia, it is recommended that they be tested for COVID-19 as soon as flu-like symptoms appear.

If the result is positive, antiviral treatment against SARS-CoV-2 is recommended. If the test is negative, the possibility of influenza will be investigated, for example by checking for contact with a confirmed influenza case. Antiviral treatment for influenza may be recommended.

There is no rapid test for RSV. It is usually not identified unless the infection requires hospitalization.

RSV infection is particularly worrying in young babies, as it can cause bronchiolitis, a serious lung infection. RSV can also cause complications, such as pneumonia, in older people and those with chronic illnesses or weakened immune systems.

How are these viral infections treated?

In most cases of viral respiratory infections, the immune system successfully fights the infection.

If the infection causes only mild or moderate symptoms, rest is the best treatment. If the symptoms are bothersome, over-the-counter medication can help.

• Fever: You can take acetaminophen (or ibuprofen) if you have a fever, but it is not necessary to bring down a low-grade fever (≤38.0 °C taken orally) in adults.
• Nasal Congestion: Preferably use a saline nasal spray or nasal irrigation. Alternatively, a decongestant may be used (nasal spray or tablet).
• Headache, muscle or joint pain: Take an over-the-counter pain reliever (acetaminophen, ibuprofen, naproxen). Ask your pharmacist for advice if you are taking other medicines, as the choice may depend on your health.
• Cough: Cough suppressants are generally only moderately effective. Drinking plenty of fluids, sucking hard candy, or taking honey (only if you are at least 1 year old) may also help reduce the irritation in the throat that triggers coughing.

All-in-one products (such as "cold and sinus") should be used with caution and only if you are not taking other medications that contain the same ingredients. Check with your pharmacist to avoid the risk of overdose.

People who are at high risk for complications if they get the flu or COVID-19 may be eligible for antiviral medication to treat their infection. Because these treatments need to be started within a few days of the onset of symptoms, it is a good idea to talk to your healthcare provider now to determine if you are in a high-risk group. These groups typically include people with weakened immune systems or chronic medical conditions.

Remember that antibiotics are not effective against a viral infection. Taking antibiotics unnecessarily increases the risk of bacterial resistance.

What is the normal course of a respiratory infection?

Most respiratory infections go through 3 main stages:

• Onset of symptoms, which may be gradual or sudden.
• Symptoms reach a plateau, a period when they are at their maximum. This can last several days, depending on the infection and the person.
• Symptoms disappear, more or less quickly depending on the symptoms and the severity of the infection.

If present, fatigue and cough are the symptoms that typically last the longest. They may persist for weeks after other symptoms have resolved.

In otherwise healthy people, a persistent cough does not require treatment if it is the only symptom left. You need to be patient. It will eventually go away.

If the cough is accompanied by fever, especially if the fever came after the other symptoms of the original infection, you should seek medical advice, as it may be a bacterial superinfection.

When should I see a doctor?

If symptoms continue to get worse after several days (no plateau), it is better to seek medical advice, especially if the person is at risk for complications. For example, if the person has difficulty breathing or gets short of breath just talking, their breathing is very fast, or their blood pressure is low, they shod see a doctor right away, especially if they are 65 years of age or older or have other medical conditions. 

If you are unsure whether or not to go to the emergency room, do not hesitate to call 811.

The best protection is vaccination!

The risk of complications from influenza, COVID-19 and RSV can be reduced by vaccination. 

Vaccination is especially important for people with more fragile health who are at risk of complications, but it is available to anyone who wants to protect themselves.

Influenza vaccination is offered each fall in advance of the flu season, which typically begins in late fall and ends in the spring.

Vaccination against COVID-19 is offered twice a year, in the fall and spring, due to the year-round presence of the virus and the short effectiveness of the vaccine (about 6 months).

Vaccination against influenza and COVID-19 is offered free of charge to people in at-risk groups across Canada. In some provinces, vaccination is also offered free of charge to anyone who wants to protect themselves, regardless of their health status. Do not hesitate to consult your pharmacist to find out the eligibility criteria for vaccination in your province.  

In recent years, new RSV vaccines have been licensed for use in Canada. They are offered to people 60 years of age and older and to pregnant women. If the mother is vaccinated during pregnancy (between 32 and 36 weeks), the vaccine will also protect the baby. This is because the mother's immune system produces antibodies against RSV, which are then passed on to the baby. The RSV vaccine is not currently publicly funded, but private health insurance plans may cover its cost.

Your pharmacist is here for you!

If you have symptoms of a viral respiratory infection, do not hesitate to seek professional advice from your pharmacist. As medication specialists, they will be able to recommend the best treatment to relieve your symptoms based on your health status.

If you have chronic health conditions or a weakened immune system, take the time to talk to your pharmacist about your eligibility for antiviral treatment for the flu or COVID-19. In some provinces, pharmacists can prescribe antiviral treatment for these respiratory infections to reduce the risk of complications.

Want to protect yourself with a vaccine? Across Canada, pharmacists can prescribe and administer vaccines, including influenza, COVID-19 and RSV vaccines.

Finally, if you have asthma or COPD, make sure it is well controlled. If your lung condition is well controlled, it will be less affected by viral infections, such as the flu, COVID-19 and RSV. Your pharmacist can help you improve your treatment to get better control if needed.