Early Flu Spike Could Strain Hospitals: Here’s how to stay protected

With hospitals under pressure, experts share why vaccinations still matter and what you can do.

What does an early spike in flu cases mean for you and your family this season? Influenza can lead to serious illness, absences from work or school, and complications for those at higher risk. It also leads to significant numbers of hospital visits each year, adding pressure to emergency departments and inpatient care. With reports of a possible vaccine mismatch making headlines, we asked public health and pharmacy experts to explain what’s happening and how effective the vaccine remains. They also outline what this means for you and how taking preventative steps can help ease pressure on the health system.

Sharing their insights are Dr. Fahad Razak from Unity Health, Dr. Vinita Dubey from Toronto Public Health, Dr. Richard Mather and Dr. Adrina Zhong from Public Health Ontario, and Professor Mina Tadrous from the Leslie Dan Faculty of Pharmacy. They bring expertise in communicable disease control and vaccine policy, sharing expert knowledge to help you make informed decisions this flu season.

About the flu vaccine

Why is the flu vaccine important?

Drs. Mather & Zhong: Influenza infection (or “the flu”) can cause a range of symptoms, with most people recovering within a week or 10 days, but it can cause severe illness and is among the top 10 leading causes of death in Canada.  Each year, influenza is estimated to cause approximately 15,000 hospitalizations and 3,500 deaths in Canada, based on data from before the COVID-19 pandemic.

The flu vaccine is our best defense against the influenza virus each year. The best way to prevent infection is to receive the flu vaccine in the fall, early in the flu season. Being vaccinated also means you are less likely to spread the flu to people close to you, including infants, children, older adults and immunocompromised individuals.

Dr. Dubey: Respiratory illnesses like the flu can make people very sick and worsen underlying health conditions, especially among seniors, people with weakened immune systems, infants and young children, and pregnant individuals. Vaccination is your best protection against serious respiratory illness.  

Is it still worthwhile to receive the vaccine?

Dr. Dubey: Getting the flu vaccine still offers better protection and can help prevent serious illness even when the vaccine is not a perfect match. It is much safer to get the flu vaccine than to get the flu. 

Dr. Razak: The vaccine remains very helpful, even if it doesn't prevent as much as it would for another strain of flu, it does reduce severity, so it is still extremely valuable.

What are the biggest misconceptions you encounter about the flu or the flu shot?

Dr. Dubey: A common myth about the flu vaccine is that it can give you the flu. The flu vaccine can’t make you sick with the flu because it does not contain the virus.

Something else we often hear is people thinking they don’t need the flu shot because they’ve had the flu before. Even if you’ve had flu in the past, it’s important to get vaccinated each season as protection decreases over time and vaccines are updated each year for the strains expected to circulate. Each year multiple strains spread, and even when the vaccine is not a perfect match, it still strengthens your protection, helping prevent serious illness and hospitalization.

If you could debunk one myth about the flu or flu vaccines, what would it be?

Dr. Dubey: That the flu vaccine doesn’t work. The flu vaccine remains our best defense against the flu. While the flu vaccine cannot guarantee absolute immunity, it can significantly reduce symptoms if you are infected and prevent serious illness and complications. 

Dr. Razak: I worry that the vaccine conversation has become incredibly complicated for people, and I just want to reinforce that these are extensively studied highly effective preventative strategies. Think about it the way you think about a seatbelt. It's not a huge conversation, you get in a car, you put on a seatbelt, you move on with your day. I'd like for people to start to think about vaccines like that. You go in once per fall/early winter season, you get your vaccines, you move on with your life. It's not a big additional conversation, and I do worry that the level of interrogation, the misinformation, disinformation, has made this huge consequential event with, from a public health perspective, it should be an easy decision, which is do the thing that reduces the effect of these illnesses on your life.

What would you say to someone who feels healthy and isn’t sure if they need the vaccine?

Dr. Dubey: Even healthy people can get sick from the flu. By getting the flu vaccine, you are also protecting others around you who may be at higher risk of serious illness – like your grandma, your sister’s new baby, or your friend with a chronic heart condition.   

Dr. Razak: These vaccines reduce severity, so it may be that you get vaccinated for the flu, you may still get the flu, but it's less severe. It means that you're home a couple of days sick on chicken noodle soup, but you're not in the emergency room, or you're not on the ward, or you're not in the intensive care unit. It's that severity of admission that we're trying to prevent as well.

Also, there's really important scientific studies now that show that getting a severe infection like flu has such an enormous inflammatory effect on your body, that it leads to downstream effects within the coming weeks, like higher rates of heart attacks and strokes. So, if a patient has flu, the chance that they'll have a heart attack or stroke goes up by four to five times higher risk within the next 30 days. So, it's a very important cascade event to other things like heart attacks and stroke.

How does increased flu vaccination benefit the broader community, especially during the holidays?

Dr. Dubey: For many, the holidays are an exciting time filled with gatherings with family and friends. Getting the flu vaccine ahead of holiday celebrations will help make it safer to take part in your festive activities. It will also help protect your loved ones. Keeping in mind it takes two weeks for your body to develop an immune response from the flu vaccine, it is important to get vaccinated as soon as you can for protection this holiday season. 

Dr. Razak: We know that if there's a greater number of vaccinated people, it does slow transmission. So, it's the idea that you are just slowing the spread of this illness throughout the system as well if you are more protected.

What advice do you have for families planning holiday gatherings to reduce their risk of spreading respiratory illnesses?

Dr. Dubey: In addition to getting vaccinated, there are additional steps families can take to reduce virus spread, and protect themselves and those who are most vulnerable in our community: 

• Consider wearing a mask, especially in crowded indoor spaces.  
• Stay home when you are sick.  
• Wash your hands often.  
• Cover your coughs and sneezes.  
• Choose well-ventilated spaces when possible.    

Each layer of protection adds up and works best when used together, especially when respiratory virus activity is high.  

Family members with health concerns such as lung and heart conditions should talk to their health care provider about what to do if they get sick this season by creating a respiratory illness care plan. 

Current flu virus and vaccine

What are you seeing in terms of flu activity so far this year?

Dr. Razak: What we look at is the southern hemisphere as a leading data point to see what we should expect here, because their winter is our summer. So, they tend to get their flu season before we do, and unfortunately, Australia, which is one of the main jurisdictions we look at, had one of the worst or worst flu seasons on record this year. So, it suggests that the strain that’s coming through the Australian experience suggests that we may have a more severe season this year.

Dr. Dubey: Toronto Public Health monitors respiratory virus activity in Toronto, including COVID-19 and flu, using our Integrated Respiratory Diseases Dashboard.

Last year, we had one of the most severe flu seasons we have had in the last ten years. While it is too early in the season to know exactly what this winter will bring, we are seeing that flu activity is starting to increase in the community, making vaccination and other protective measures especially important to help prevent virus spread.

Drs. Mather & Zhong: In recent weeks as we head into the beginning of flu season in Canada, we are also seeing signs that the proportion of influenza cases in Canada caused by A(H3N2) is increasing and has become the dominant subtype. Among A(H3N2) cases with subclade information available, subclade K is predominant.

Historically, we have seen that seasons where influenza A(H3N2) predominates are associated with higher rates of hospitalizations overall.

The exact trajectory of the current flu season is hard to predict. However, what remains consistent every year is that getting the flu vaccine is the best way to protect yourself from getting and spreading the flu. 

Reports in the media state the vaccine is not a match for the virus currently spreading, how effective is it and what should the public understand about how protection works?

Drs. Mather & Zhong: There are multiple strains of influenza that circulate each fall and winter. Strains that are currently circulating include influenza A (of which there are two strains: H3N2 and H1N1) and influenza B. The flu vaccine offers protection against all three strains.

Influenza viruses evolve over time, and each year the World Health Organization selects the influenza strains for the vaccine based on global surveillance data. Production of the vaccine takes up to 6 months and the virus may continue to evolve during this time, resulting in the influenza strains that circulate in the community being different from the strains selected for the vaccine. Differences between the circulating influenza strains and the ones included in the vaccine are called a “mismatch”, which might translate to lower observed (i.e., real world) vaccine effectiveness. A “mismatch” does not always mean the vaccine is ineffective – it may still offer significant protection, especially against severe illness and hospitalization.

Sources: World Health Organization, Sabaiduc et al, 2025, ECDC

Dr. Razak: We don't know what strain of flu is going to come through until we are very much into the flu season. We do our best to estimate that based on what we are seeing from emerging variants of the flu throughout the world. The worry this year is that the strain of flu that is coming through historically has been less well-protected against by our vaccines. This is H3N2. And we see, on average, the seasons where that becomes the dominant strain tend to have worse outcomes, more severe illness, more people in hospital. The vaccine remains very helpful, even if it doesn't prevent as much as it would for another strain of flu, it does reduce severity, so it is still extremely valuable.

Drs. Mather & Zhong: In laboratory studies, it appears that the immune response generated by this season’s influenza vaccine is not as strong against H3N2. However, it is important to note that this “mismatch” shown in laboratory testing may not be reflective of real-world vaccine effectiveness.

Research findings from the UK Health Security Agency show that in an early season analysis, preliminary estimates are that this season’s influenza vaccine is currently 70% to 75% effective at preventing hospitalization in children (aged 2 to 17 years), and 30% to 40% effective in adults. These observed vaccine effectiveness estimates are similar to what we have seen in adults in recent years in Canada.

These early findings from the UK are encouraging and show that even in a season where we have a “mismatched” flu vaccine, immunity from the vaccine still matters. It can be the difference between being hospitalized, or not.

Sources: Sabaiduc et al, 2025; Kirseborn et  al, 2025

System-level impact

How does widespread vaccination reduce the burden on hospitals and emergency departments?

Dr. Dubey: More people getting flu vaccines means less people getting seriously ill from the flu, which means fewer flu-related emergency visits and hospital admissions. It also helps prevent complications in people at higher risk of serious illness, reducing the need for urgent care. By keeping more people healthier, flu vaccination preserves hospital capacity for other emergencies and ongoing care needs. 

Why is maintaining hospital and ICU capacity critical during the winter months?

Dr. Razak: The most severe manifestations of influenza, RSV, and COVID will lead typically to an ICU admission. So, if you think about our resource, we have the hospitals themselves, which are hundreds of beds per hospital in the large hospitals. But then the most specialized area for the sickest of the sick, and again, not just infection, also heart failure, cardiogenic shock, hemorrhage, and bleeding; it's the intensive care unit. So, this is that area where if you suddenly get a surge of patients who have severe respiratory illness, that ICU capacity becomes extremely strained as well. We have a fixed capacity. Anything that pushes on it in a significant way is of concern.

How does reducing flu-related hospitalizations help ensure care is available for emergencies and serious non-flu conditions?

Dr. Razak: Think about the hospitals as the unified structure to provide care for everything that is acute, surgical, medical, trauma, obstetrics, mental health, it all goes to one place. So, when you have this one thing starting to overwhelm capacity, all of the hospital starts to become affected. More demands on imaging, more demands on nursing staff, the beds are being taken up. So, you really want to, from a system point of view, think about your individual health, of course, but collectively, when we go out and prevent and take these vaccines, we're helping protect our shared asset, which is the hospitals.

What systemic challenges worry you most during a heavy flu season?

Dr. Razak: If you think about Ontario hospitals as a system, they are always running very near to the edge of capacity. If you are running near 100% occupancy, even in the best of times, when you have a surge of admissions that come in, you overwhelm that capacity.

So, the spinout effect is worries around deterioration of care quality. No one wants to be treated in a hallway, plus our ability to monitor and care for someone in a hallway is not the same as in a traditional hospital bed. And these broader spin-out effects on the system, where other parts of the system that have nothing to do with infections start to get delayed in terms of access or procedures as well. And the reason why this is so important is that our hospitals are a centralized capacity for everything. So, remember, if there is a heart attack, it's the hospital. If there's a car accident, it is the hospital. And of course, if there's an infectious illness, it is also the hospital. So, when this one area of the system starts to overflow hospital capacity, it has these kind of broad spin-out effects everywhere.

Access to vaccines

How do pharmacies and distributors ensure vaccines are available in communities across the country?

Prof Tadrous: This is a centralized process that is coordinated. The purpose is that all pharmacies can sign up to the program and have more hours and access to them. You can easily reach out to pharmacies online or ahead of time to book an appointment and make sure they have vaccine for you.

What happens behind the scenes to prevent shortages, especially during peak vaccination periods?

Prof Tadrous: There is coordination to ensure some places don’t hoard vaccine unless they need them. There is also mapping of demand that leads to central government procurement reaching out to manufacturers ahead of time to try to get supply. Shortages do occur and are happening now. In these times there is also prioritization of higher-risk populations to ensure they are vaccinated.

How does demand around the holidays affect distribution or availability?

Prof Tadrous: The biggest concern is time and locations getting the vaccine on time and having times for you to have it administered. I would plan and not wait until the week before the holidays.

What do you wish more people understood about the logistics of getting a flu vaccine into a clinic or pharmacy?

Prof Tadrous: Pharmacies don’t make money on the vaccination they don’t have an upcharge of any sort and actually the fees they get are low. They do this as a service to their patients and the community. Also planning for vaccines is super centralized and is a best guess based on previous demand and needs work.

Final Message

What is one simple message you want the public to take away this season?

Dr. Dubey: The flu vaccine remains safe, effective and the best way to protect yourself against getting very sick from the flu. 

Dr. Razak: Two-thirds of all adults who end up in hospital with the flu are not vaccinated and 90% of all children who end up in hospital are not vaccinated. So that gives you a sense of the level of protection of the vaccine.

About the experts