The Influenza Vaccine

Nurses have seen firsthand that influenza can be very serious. Not only can the symptoms be severe, but some people are at a much higher risk of complications and other life-threatening infections, such as viral or bacterial pneumonia. Preventing transmission through vaccination is the best way to protect ourselves and our communities. Here's a list of people at much higher risk of facing serious disease, complications and death:

• All pregnant persons, particularly those in the second half of their pregnancy, are at very high risk of hospitalization following a severe infection.
• Seniors 65 years and older, and people of any age who are residents of long-term care and assisted living facilities.
• Infants and very young children.
• Indigenous peoples, due to inequitable access to the social determinants of health. 
• People with lung or heart diseases, with weakened immune systems and other chronic health conditions.

Because everyone is at risk. Symptoms can vary from mild to severe and sometimes affect people for weeks, and put them at greater risk of other infections that can cause serious complications. On average, many British Columbians get sick with severe influenza disease each year, requiring significant medical support, including hospitalization. Public health guidelines advise that everyone should receive the vaccine in order to prevent serious illness or transmission, and alleviate strain on the health-care system.

Yes, it’s the number one protection from four of the most common strains of influenza. Once approved and in use, public health researchers monitor in real life the strength of the vaccine against actual virus strains circulating during a particular year. They estimate vaccine effectiveness (VE) for each circulating strain. Some years are better than others.

Because vaccines are based on the best prediction models of which strains will be circulating, they are only predictions and VE does vary from season to season. Typically, we know the predominant strains from year to year – often two strains of Influenza A and the most common strain of Influenza B. But when people say, “the influenza vaccine isn’t effective this year”, what that usually means is that one of the four predicted strains (typically one of the Influenza A strains) is not well-matched. 

Even when VE isn’t as high as expected, the vaccine will still provide significant protection that would not have been there without a vaccine. The influenza vaccine is still effective against the other three predicted strains. So even though it’s not always perfect, it still provides the best defence against serious illness.

The influenza vaccine is designed to generate a strong immune response in most recipients. Vaccine manufacturers are responsible for demonstrating that their annual vaccine generates a strong immune response through antibody levels and that their vaccine has an excellent safety profile. However, older people and people living with medical conditions related to immunosuppression can have a weaker response.

This is a common misconception. Because the vaccines are made from the killed influenza viruses that do not cause infection, the vaccine is inactive and poses no risk of infection.

Though extremely uncommon, allergic reactions can happen. That’s why it’s important to stay at the clinic for 15 minutes after receiving any vaccine. The life-threatening allergic reaction called anaphylaxis happens in less than 1 in a million people receiving the vaccine. Symptoms may include hives, difficulty breathing, swelling of the throat, tongue or lips. Should this reaction occur, the health-care provider is prepared to treat this reaction right away. 

It is also good to know that even egg-allergic individuals may be safely vaccinated against influenza using any influenza vaccine, including egg-based vaccines and the live attenuated vaccine, without prior influenza vaccine skin test and with the full dose, irrespective of a past severe reaction to egg and without any particular consideration, including vaccination setting.

Yes. Like all vaccines approved for use in Canada, the influenza vaccine must meet very strict safety regulations. It has to be manufactured under high-quality production processes, and show high efficacy and be safe. Health Canada’s independent drug and vaccine authorization process is recognized around the world for its high standards and rigorous review. The influenza vaccine has been used in Canada for decades. The quantity and quality of evidence of safety and effectiveness are significant. It’s backed by vaccine clinical trials, post-marketing studies, continuous adverse event monitoring and surveillance, clinical practice, epidemiology and more.

If there are any side effects, they are usually minor. The influenza vaccine has been tested and proven to be safe and predictable following immunization. According to clinical trials, the BC Centre for Disease Control’s Adverse Effects Following Immunization (AEFI) monitoring and surveillance system, and the experience of clinicians in their practice, the majority of reported post-vaccination effects are expected reactions. Aside from very few circumstances, these reactions are mild in nature and last only up to a few days.

Services vary by location. Use the Influenza (Flu) Clinic Locator to find the nearest influenza vaccine clinic. Let's stay safe and healthy this year.