Influenza (Flu) verse Corona Virus (COVID-19): How to tell the difference. Both Influenza (Flu) and COVID-19 are contagious respiratory illnesses, however, a different virus is responsible for each.
Some symptoms of respiratory illnesses, including influenza and COVID-19, are similar and thus differentiating between these cannot be done based on symptoms alone. Testing is required to identify the illness and confirm its diagnosis. Some members of the population may be infected by both influenza and COVID-19 viruses at the same time and suffer from symptoms of both.
Both viruses may be spread from person-to-person, within a two-meter distance from one another. Both viruses are spread by the expulsion of infectious virus-containing particles released when infected individuals cough, sneeze, or speak. In certain areas such as poorly ventilated indoor areas, infected viral particles might be spread further and result in infections. It may be possible to become infected following physical contact with an infected individual, surface or object where the virus is present and then touching their own mouth, nose, or eyes.
Although both Viruses spread in a similar manner the COVID-19 virus seems to spread more quickly and easily to a greater proportion of the population resulting in continual spreading amongst members of the population over time.
As COVID-19 is a relatively new virus, there remains a lot to learn about the Virus and its long term side effects. However, as a larger percentage of the population becomes fully vaccinated against COVID-19, the spread of the COVID-19 virus should decline. Current data indicates that the COVID-19 virus proliferates more readily than Influenza.
The below information compares COVID-19 and flu, given the best available information at the current time,
Similarities for both COVID-19 and influenza may have varying signs and symptoms, which range from asymptomatic to severe symptoms. Common symptoms shared by both include, but are not limited to:
- Pyrexia / feeling feverish / Chills
- Cough
- Shortness of breath / difficulty breathing
- Fatigue (tiredness)
- Sore throat
- Runny or stuffy nose
- Muscle pain or body aches
- Headache
- Vomiting and Diarrhoea
- Change in or loss of taste / smell, although more frequent for COVID-19
Both viruses may take one or more days post-exposure before the infected individual experiences symptoms.
With influenza, a person typically experiences symptoms from 1 to 4 days post-infection, whereas with COVID-19 an infected individual may experience symptoms 2 to 14 days post-infection.
Both viruses are transmissible for at least 1 day before symptoms present but COVID-19 may result in the infected individual being contagious for a longer period of time.
Older children and adults with influenza remain contagious for around 7 days after infection, however, Infants and immunocompromised individuals may be contagious for longer.
COVID-19 may be contagious 2 days prior to symptom onset, possibly earlier, and remain contagious for a minimum of 10 days following the first appearance of symptoms. If asymptomatic or symptoms are no longer present, the individual may remain contagious for at least 10 days after a positive COVID-19 test. Individuals hospitalized due to severe disease and immunocompromised individuals may be contagious for longer periods.
Both may result in severe illness and complications. Individuals who are deemed to be at greater risk include those with certain underlying health conditions as well as infants, children and pregnant individuals. COVID-19 seems to be responsible for more serious illnesses and may result in hospitalization and possibly death, which may occur even in healthy people.
Both viruses may result in complications, such as Pneumonia, Respiratory Failure, Acute Respiratory Distress Syndrome, Sepsis, Cardiac injury, Multiple-organ failure, exacerbation of chronic medical conditions, Inflammation of the essential organs or body tissues, Secondary infections (bacterial/fungal / Viral).
Most influenza sufferers recover on their own within two weeks but some may experience severe complications, as listed above. Secondary bacterial infections are more common with influenza than with COVID-19.
Additional complications due to COVID-19 may include Blood clots within vessels of the lungs, heart, legs or brain. Some COVID-19 sufferers may potentially develop post-COVID conditions or multisystem inflammatory syndrome (MIS), a serious but rare condition associated with COVID-19 resulting in various body parts becoming inflamed, including heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs.
Long COVID is a range of symptoms that may last weeks/ months or longer following with COVID-19 or may even appear weeks after infection. Long COVID can happen to anyone previously infected by COVID-19.
Individuals who have had complications as a result of either virus may receive supportive medical care to help relieve symptoms and complications. Influenza may be treated using regulator approved Influenza antiviral drugs. Individuals hospitalised with flu or at increased risk of complications are recommended to be treated as soon as possible with Influenza antiviral drugs following the onset of the illness.
The Medicines and Healthcare products Regulatory Agency (MHRA) has approved Ronapreve for use in the prevention and treatment of acute COVID-19 infection in the UK. The MHRA has also approved the First oral antiviral for COVID-19, Lagevrio (molnupiravir). Currently approved COVID-19 Vaccines for use in the UK include Moderna vaccine, Oxford/AstraZeneca vaccine and Pfizer/BioNTech vaccine. The NHS has advised that the Janssen vaccine for COVID-19 will be made available later this year.