Question: What is the difference between COVID-19 and influenza

Answer passage (source: WHO):
page_title: Q&A: Influenza and COVID-19 - similarities and differences
section_headers: How are COVID-19 and influenza viruses different?
section_content: The speed of transmission is an important point of difference between the two
viruses. Influenza has a shorter median incubation period (the time from
infection to appearance of symptoms) and a shorter serial interval (the time
between successive cases) than COVID-19 virus. The serial interval for
COVID-19 virus is estimated to be 5-6 days, while for influenza virus, the
serial interval is 3 days. This means that influenza can spread faster than
COVID-19.  
Further, 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. In contrast, while
we are learning that there are people who can shed COVID-19 virus 24-48 hours
prior to symptom onset, at present, this does not appear to be a major driver
of transmission.  
The reproductive number – the number of secondary infections generated from
one infected individual – is understood to be between 2 and 2.5 for COVID-19
virus, higher than for influenza. However, estimates for both COVID-19 and
influenza viruses are very context and time-specific, making direct
comparisons more difficult.  
Children are important drivers of influenza virus transmission in the
community. For COVID-19 virus, initial data indicates that children are less
affected than adults and that clinical attack rates in the 0-19 age group are
low. Further preliminary data from household transmission studies in China
suggest that children are infected from adults, rather than vice versa.  
While the range of symptoms for the two viruses is similar, the fraction with
severe disease appears to be different. For COVID-19, 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. These
fractions of severe and critical infection would be higher than what is
observed for influenza infection.  
Those most at risk for severe influenza infection are children, pregnant
women, elderly, those with underlying chronic medical conditions and those who
are immunosuppressed. For COVID-19, our current understanding is that older
age and underlying conditions increase the risk for severe infection.  
Mortality for COVID-19 appears higher than for influenza, especially seasonal
influenza. While the true mortality of COVID-19 will take some time to fully
understand, the data we have so far indicate that the crude mortality ratio
(the number of reported deaths divided by the reported cases) is between 3-4%,
the infection mortality rate (the number of reported deaths divided by the
number of infections) will be lower. For seasonal influenza, mortality is
usually well below 0.1%. However, mortality is to a large extent determined by
access to and quality of health care.

Reviewer feedback on this answer:
This compares and contrast both COVID and FLU. This also outline how they spead
This answer mentions and explains, in full detail, many differences between to two diseases.
This is a direct answer to the question. This answer contains detailed information on the differences between covid-19 and influenza.

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