Some Q&A on Flu in the Context of COVID-19

What danger influenza (flu) poses this year? What people can do to stay healthy in this possible “twindemic” of flu and COVID-19? Dr Richard Pebody, who leads the High-threat Pathogen team and the Surveillance and Laboratory pillar of the COVID-19 Incident Support Management Team (IMST) at WHO/Europe, gives us some suggestions.

1. What is flu and why is it concerning?
Flu is a contagious respiratory illness caused by influenza viruses that infect the nose, throat and sometimes lungs. It can cause mild to severe illness and, for some people with underlying conditions, can unfortunately lead to death. In a normal year, around 70 000 people die from flu in the WHO European Region.

2. Why should we be particularly worried about flu this year?
With international travel resuming and many societies opening up again, there is more potential for the flu virus to be introduced and to spread than last year. As flu rates were so low in 2020/2021, people might be more susceptible to the virus this year. This is particularly concerning as we go into the winter months, with more people mixing indoors and travelling, adding to the risk of catching and spreading the virus.
We’re also still in the midst of the COVID-19 pandemic, with the highly transmissible Delta variant in circulation, which could lead to a potential “twindemic” of influenza and COVID-19 this winter. Having both viruses co-circulating could have severe consequences for vulnerable people and place increased pressure on health systems at a time of year when hospitals are often at their busiest anyway.

3. What are the differences between COVID-19 and flu? How can I tell if I have one or the other? What should I do if I have symptoms?
Both viruses are highly infectious respiratory diseases and share many of the same symptoms, such as coughing, fever, shortness of breath, and/or loss of taste and smell. Because of the difficulty in distinguishing the diseases from symptoms alone, if you are symptomatic you should isolate yourself from other people to reduce the risk of the infection spreading, particularly to vulnerable people, and get tested for COVID-19 as soon as possible. While both diseases can cause serious illness, COVID-19 is more likely to lead to health complications, admission to hospital and, in some cases, death – so getting tested is essential.

4. Who would you recommend get vaccinated against the flu virus and when should they do it?
WHO recommends that people from the following 5 priority groups get vaccinated before the flu season starts, or as soon as possible thereafter. This is usually around October to November, after vaccines become available.

(1) Health-care workers. As health-care workers are more exposed to flu through their work, their chances of passing the infection on to others, including vulnerable patients at risk of severe disease, are increased. We also rely on these workers to run our health services, so we need them to stay healthy at work, not be off sick with the flu, particularly at a time of year when health services are often under the most pressure.

(2) Older people over 65 years. As the immune system weakens with age, our bodies become less effective at fighting infections, including flu. This means older people have a greater risk of developing serious illness, may need hospitalization and could even die from the disease.

(3) People with underlying conditions, such as diabetes, lung disease or heart disease. Weakened immune systems can increase the risk of severe illness, hospitalization and potentially death from flu.

(4) Pregnant women. Evidence shows that pregnant women are more prone to developing severe flu, which can have a negative impact on the unborn child. Vaccination protects the pregnant woman, the fetus and the baby once born.

(5) Children under 5 years. Young children are more likely to develop more severe illness, and have the potential to infect others, including older relatives.

5. Which types of influenza does the vaccine protect you from?
There are 2 major human influenza virus types, influenza A and influenza B, which lead to annual flu epidemics (often referred to as the flu season). In Europe, we use both trivalent vaccines (to protect against 3 influenza strains) and quadrivalent vaccines (to protect against 4 strains) that cover both of these virus types.
This article is originally from WHO website, Europe Health topics of Influenza.