Why has the spread of COVID-19 made it more important than ever to have your annual flu vaccine?

"The typical symptoms associated with COVID-19 disease are similar to those of influenza (the flu)," says Discovery Health's Head of the Centre for Clinical Excellence, Dr Noluthando Nematswerani.

"It is therefore easy to understand why people might think having a flu vaccine protects them against COVID-19 infection - and it's important to understand why this is not the case."

How do vaccines work?

Vaccines are designed to protect us from developing serious illness after we are exposure to a pathogen like a virus, bacterium or other kind of microorganism. Vaccination therefore decreases the chance that we will need to be admitted to hospital severe symptoms or complications linked to an infection - like the flu, in the case of the flu vaccine, or COVID-19 in the case of the COVID-19 vaccine.

Why doesn't a flu vaccine protect us against COVID-19 - and vice versa?

"First things first. Influenza and COVID-19 are not part of the same virus family. While the symptoms may be similar, their origins are different," Dr Nematswerani points out. "Understanding this is important. It is entirely possible to be exposed to both viruses and then develop one or both of these illnesses."

Influenza has been around a lot longer than COVID-19. This means that a substantial amount of research has already been done to better understand its patterns, risk factors and how it can be prevented. This research allows scientists to develop a vaccine for each year's strains of flu.

The flu vaccine provides protection for the strain of flu that is expected in each year's flu season. It will not protect you against COVID-19.

So, if the flu vaccine can't prevent serious COVID-19 illness, why should we all get a flu vaccine?

The flu vaccine won't protect you against COVID-19, but it will protect you against serious illness if you contract the flu. Since the 2021 flu season overlaps with winter and the current outbreak of COVID-19, the National Institute for Communicable Diseases (NICD) in South Africa has recommended that every South African citizen receive a flu vaccination ahead of influenza season.

If a person becomes unwell with any kind of viral infection, their immune system typically become weakened for a while. This makes a person even more susceptible to any other infectious conditions that may be prevalent at the time.

"By protecting yourself against one contagious infection - the flu - you should be able to reduce your level of risk somewhat against the other," says Dr Nematswerani. "The flu vaccinate won't prevent you from contracting the flu or COVID-19 infection, but it can help to ensure that you experience far less severe illness and prepare your immune system ahead of your exposure to these diseases so that it's primed to fight them off as well as possible."

Getting your flu vaccine helps to ensure that healthcare professionals are freed up to respond to treating COVID-19 infections as fewer people need to be treated for severe flu. Ultimately, fewer flu infections result in less of a burden on hospitals, and more time for doctors and hospitals to focus on treating people who have serious COVID-19 illness.

Flu vaccines are generally available to the public from March or April every year for the duration of the Winter season. It is advisable to receive a flu vaccination well before the flu season sets in. However, the vaccine will still be effective if received at any point during the winter months.

"It's important to remember that a flu vaccine is developed to be administered annually," explains Dr Nematswerani. "This is because there are many different strains of the flu virus and the most prominent ones may vary from year to year. The annual flu vaccine is therefore formulated to target the flu strains expected to be in circulation during a specific year and season."

Are there ways to tell the difference between the two infections?

"It's not all that easy to differentiate between flu and COVID-19 illness based on symptoms alone," says Dr Nematswerani. "You need to take into account other risk factors, namely recent travel to high-risk areas, or known exposure to someone with COVID-19."

A healthcare professional is likely to ask questions such as the following when assessing a patient:

• Has a person with obvious signs and symptoms of infection recently travelled to an area known to be experiencing an outbreak of COVID-19?
• Has a person recently been exposed to someone displaying COVID-19 symptoms?
• Has a person been in the company of someone who has received a confirmed diagnosis of COVID-19?

What do the flu and COVID-19 have in common?

Both are viral illnesses and there is some overlap in the symptoms that present for each illness. This means that the general preventative measures we practice to reduce the risk of spread and transmission of COVID-19 should also work to keep us safe from the flu. Here's a reminder of the measures:

• Wear appropriate face masks when in public (and avoid touching them)
  • Find out all you need to know about wearing a face mask the right way!
• Frequently wash (use soap and water for at least 20 seconds) or sanitise our hands
• Practice physical distancing
• Stay at home when sick, practicing cough and sneeze etiquette and
• Quarantine for 10 days when exposed to someone who has COVID-19 and self-isolate for 10 days (or more, as required) when we contract COVID-19

Who should prioritise getting a flu vaccine?

"It is considered safe for pregnant women to have a flu vaccine administered during any stage of pregnancy. This will help to reduce the risk of serious illness during pregnancy and also better protect a baby from flu once he or she is born," she says.

People who are older than 65 or who have pre-existing health conditions should definitely receive a flu vaccine. Anyone with a weakened or compromised immune system is also vulnerable to the flu infection.

"These individuals are considered at higher risk of serious illness linked to the flu and should receive a flu shot ahead of the flu season, especially in 2021 when we face the double whammy of COVID-19 and the flu over the flu season," says Dr Nematswerani. "

Can I expect side effects after having a flu shot?

"Don't panic. Side effects from the flu vaccine are rare. The most common side effect is a slight swelling and redness at the site of the injection. Otherwise more rarely you may experience a mild or low-grade fever, headache, muscle or joint discomfort or pain," she adds.

It is best to treat mild symptoms related to having the flu vaccine in the way you normally would a bout of the flu or seasonal cold. If the symptoms concern you for any reason, it is best to seek the advice of a medical professional.

These articles, written for previous flu seasons, contain really excellent and still current information to help you to better understand flu vaccines:

Top questions for your doc about the flu vaccine and the flu

You and the flu: what your GP wants you to know

Does hand hygiene really help? Facts to help you avoid the flu