- Corona viruses are a large family of viruses, some causing illness in people and others that circulate among animals, including camels, cats and bats.
- Corona viruses are zoonotic viruses i.e. they are transmitted between animals and people.
- Corona virus disease is now commonly known as COVID-19.
Most of us are usually confused with the similarities and differences between COVID-19 and Influenza as these two have similar symptoms and disease presentation as well. So, let us have a look at the similarities and differences between COVID-19 and Influenza as described by World Health Organization (WHO).
Similarities between Influenza and COVID-19:
- Firstly, COVID-19 and influenza viruses have a similar disease presentation. That is, they both cause respiratory disease, which presents as a wide range of illness from asymptomatic or mild through to severe disease and death.
- Secondly, both viruses are transmitted by contact, droplets and fomites. As a result, the same public health measures, such as hand hygiene and good respiratory etiquette (coughing into your elbow or into a tissue and immediately disposing of the tissue), are important actions all can take to prevent infection.
Differences between Influenza and COVID-19:
|Basis of difference||Influenza||COVID-19|
|Speed of Transmission||Shorter median incubation period (time from infection to appearance of symptoms)||Longer median incubation period than influenza|
|Serial Interval (the time between successive cases)||Shorter serial interval. The serial interval for influenza is 3 days.||Longer serial interval. The serial interval for COVID-19 virus is estimated to be 5-6 days|
|Speed of Spread||Can spread faster.||Spreads slower than Influenza|
|Time of Transmission||Transmission in the first 3-5 days of illness, or potentially pre-symptomatic transmission –transmission of the virus before the appearance of symptoms – is a major driver of transmission for influenza||We are learning that there are people who can shed COVID-19 virus 24-48 hours prior to symptom onset. But, at present, this does not appear to be a major driver of transmission|
|Reproductive Number||The number of secondary infections generated in case of influenza is less compared to COVID-19.||The number of secondary infections generated from one infected individual – is understood to be between 2 and 2.5 for COVID-19 virus|
|More vulnerable population||Children are important drivers of influenza virus transmission in the community.||Initial data indicates that children are less affected than adults and that clinical attack rates in the 0-19 age group are low.|
|Fraction of infection||Fractions of severe and critical infection is less compared to COVID-19.||Fractions of severe and critical infection would be higher than influenza infection. Data to date suggest that 80% of infections are mild or asymptomatic, 15% are severe infection, requiring oxygen and 5% are critical infections, requiring ventilation|
|Who Are At More Risk?||Those most at risk for severe influenza infection are children, pregnant women, elderly, those with underlying chronic medical conditions and those who are immunosuppressed.||As per the current understanding, older age and underlying conditions increase the risk for severe infection of COVID-19.|
|Mortality Ratio||Mortality is less compared to COVID-19. For seasonal influenza, mortality is usually well below 0.1%.||Mortality for COVID-19 appears to be higher than influenza, especially seasonal influenza. As per the data so far, crude mortality ratio (the number of reported deaths divided by the reported cases) is between 3-4%.|
|Availability of Vaccines/Therapeutics||Antivirals and vaccines available for influenza||There are currently no licensed vaccines or therapeutics for COVID-19|