The winter collision of influenza & COVID-19

Views in this article should not be in replacement of medical advice. If you have symptoms of a respiratory infection, please speak to and follow the advice of a Healthcare Professional.

Since the start of the COVID-19 pandemic, viral infections that interfere with normal breathing (called respiratory infections) have gained much attention and debate worldwide.

Through exposure to information in the news and discussions on social media, people all over the world have rapidly learnt more and more about respiratory infections. However, this public debate can lead to conflicting information about how best to prevent, identify and treat respiratory infections, leaving many of us confused and uncertain about what’s fact or fiction.

So, we asked Roche’s virology expert Dr Aeron Hurt, Principal Global Medical Science Director, COVID-19 and Influenza, to help shed light on how to prevent, diagnose and treat COVID-19 and influenza, and his predictions for the future of these infections.

How serious are respiratory infections and who is at the most risk?

“In the past, people may have been a bit dismissive of viruses that cause respiratory infections such as influenza. Many probably don't realise that this virus alone can cause up to 650,000 respiratory related deaths and millions of hospitalisations each year.1,2,3,COVID-19 has demonstrated the huge impact that respiratory viruses can have on people's lives.4 For young children, elderly people, those whose immune systems cannot fully protect them from illness, or those with long-term conditions such as high blood pressure or asthma, respiratory viruses can cause severe symptoms which may even be fatal.5,6 Even if you aren’t classed as high-risk, serious complications can still arise after infection.2,7 I’m hopeful that the COVID-19 pandemic, if anything, has made people realise just how serious respiratory viruses can be.”

In 2020 and 2021, there were news reports that influenza cases were at a record low during the COVID-19 pandemic. Has the influenza virus become extinct?

“In 2020 and 2021, the world was heavily burdened by COVID-19 and many protective measures were put in place to stop the spread of this virus, including social distancing, mask wearing, and limits on gatherings.8,9 These measures also stopped the spread of other respiratory viruses, so we saw very low levels of influenza across the globe during this time. However, influenza has not gone away or become extinct. As people resume normal life again, for example by going back to the office, returning to school, or attending theatres and concerts, I expect that respiratory viruses, like influenza, will begin to spread again, particularly during the winter months.10

Should we expect a more severe or widespread influenza season in 2022?

“While we may not see pre-pandemic levels of influenza this winter, it is reasonable to expect more widespread influenza cases this year, in fact we are already seeing the US and Europe reporting a significant rise.10,11,12 Influenza is likely to have an impact in countries where social distancing, mask wearing, and other pandemic-related behavioural changes are no longer in place, and where COVID-19 and influenza vaccination rates are low.7,9

Could we be heading for an influenza and COVID-19 ‘twindemic’?

“Possibly.10,12 The concern I have about a ‘twindemic’, where influenza and COVID-19 spread through communities at the same time, is that each of these viruses alone can cause enough illness and disease to fill hospitals and intensive care units. The prospect of having two viruses around at the same time to potentially cause double the impact in winter is very unsettling.3,8,13 That is why it is important we ensure people are vaccinated against COVID-19 and influenza to help protect people from becoming seriously ill. It is important that we rapidly diagnose infections and, where appropriate, deliver medicines, such as influenza antivirals, that help to slow the spread of disease, prevent people from being hospitalised and avoid severe symptoms. This could in turn reduce the pressure faced by hospitals. As mentioned previously, the most likely places for COVID-19 and influenza to spread this upcoming winter are those communities with low vaccination rates and lack of protective measures.9,12,14

Do you think we will see more SARS-CoV-2 variants emerge this year?

“Unfortunately, respiratory viruses like SARS-CoV-2 (which causes COVID-19) and influenza mutate for a living! As these viruses spread, they have more opportunities to mutate, leading to the emergence of the new variants we’ve seen over the last year, including the faster spreading Delta and Omicron variants of SARS-CoV-2. Whilst some variants may appear and disappear, others stick around, especially if they spread more quickly.15,16,17 Widespread global COVID-19 vaccination can help prevent new variants by reducing spread of the virus.18 I'm a strong advocate for a multi-tooled approach to dealing with SARS-CoV-2, influenza and other respiratory viruses, that involves getting vaccinated to provide some prevention, rapid testing to detect infections early, and antiviral treatments to reduce the impact of infections when they occur. Taking measures to reduce the spread of infection is the best way to slow the emergence of new variants and to protect yourself and those around you this winter.9

Are vaccines our only protection against COVID-19?

“Whilst vaccines are our main form of protection, there is also a growing arsenal of treatments for COVID-19, with more clinical trials underway.17,19 During the pandemic, we saw unparalleled collaboration between scientists, the pharmaceutical industry, governments, and non-profit organisations, all working together to help research, identify and develop the necessary tools to protect us against COVID-19. I continue to be amazed at the astonishing pace with which science has helped improve the ways we can prevent, treat, and manage COVID-19. We have seen this in the rapid development of mRNA vaccines for example, but also with the development of new treatments and the repurposing of existing medicines so that we may treat every stage of the disease, as well as prevent infection entirely.17,20 Treatments that target the virus and aim to stop it from replicating in the body, such as monoclonal antibodies, thereby reduce the likelihood of symptoms worsening or becoming severe. These antibody therapies may also play a key additional preventative role in the future, particularly for those immunocompromised individuals who are not sufficiently protected by vaccination. In some people who are hospitalised with COVID-19, the virus triggers a potentially fatal immune system overreaction, and anti-inflammatory treatments have been a vital tool in saving the lives of these people.21,22,23

Does getting vaccinated against influenza mean you won’t get the influenza virus?

“No, the influenza vaccine is not 100% effective. Every year, scientists do their best to predict the most widespread strains of influenza and develop the most up-to-date vaccine to combat them. Nevertheless, even when the predictions are good and the match is correct, the influenza vaccine is typically only about 40 - 60% effective. Unfortunately, the vaccine is even less effective in the elderly as our immune system’s response to vaccines becomes 'less active' as we age, therefore elderly people are one of the most vulnerable members of our society.24 Though not perfect, the influenza vaccine remains the best prevention tool we have in the fight against influenza, but there are treatments, such as influenza antivirals, that when taken within the first 48 hours of developing symptoms, can reduce the spread and lessen the symptoms if you do get infected.13,24

If you get infected with a respiratory virus, how can you know whether it’s influenza, COVID-19 or both?

“If a patient is experiencing influenza-like symptoms, taking a lateral flow (rapid antigen test) or PCR test to confirm whether you are infected with COVID-19 or influenza can help your doctor decide on the best course of treatment sooner, to help you get better faster and protect those around you.9 Through early testing, we can help support communities globally, to ensure they can be treated early and take other actions, such as isolating, to reduce the spread of infection and ultimately help people feel well. If you are unable to test yourself, doctors and healthcare professionals may be able to diagnose influenza and other respiratory infections based on a patient’s symptoms and knowledge about how common the virus is at the time in that specific community. Or, if additional tests are needed to help decide on the best course of treatment or eliminate any uncertainty, doctors may use a test that can tell the difference between COVID-19 and influenza, which will confirm the diagnosis.14,25,26

What’s the best course of action if I do get infected with influenza or COVID-19?

“If you have received a confirmed diagnosis of influenza or COVID-19, it’s very important to follow your doctor's advice immediately and adhere to any isolation requirements to protect those around you.9 If you are prescribed medication, start it right away, especially if you are at high risk of developing severe illness. The earlier someone takes an influenza antiviral, the better — because these treatments are most effective when taken within the first 48 hours of developing symptoms.2,14

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  20. Centers for Disease Control and Prevention. Understanding mRNA COVID-19 Vaccines. [Internet; cited January 2022]. Available from:

  21. JAMA Network. Monoclonal Antibodies for Prevention and Treatment of COVID-19. [Internet; cited January 2022]. Available from: Monoclonal antibodies provide an alternative,could last weeks or months

  22. National Institute of Health. COVID-19 Treatment Guidelines. Clinical Management Summary. [Internet; cited January 2022]. Available from:

  23. National Institute of Health. Anti-SARS-CoV-2 Monoclonal Antibodies. [Internet; cited January 2022]. Available from:

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  26. Centers for Disease Control and Prevention. Overview of Testing for SARS-CoV-2 (COVID-19). [Internet; cited January 2022]. Available from:

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