As many countries around the world decide to coexist with Covid-19, the question arises: can this be done in a manner similar to seasonal influenza?
According to an analysis published in The Guardian, numerous comparisons between Covid-19 and seasonal influenza have been made during the pandemic, highlighting their common characteristics. Both are respiratory viruses that spread easily and can be deadly. They can be transmitted through droplets and surfaces contaminated with the virus, and share several symptoms such as fever, cough, headache, and fatigue.
However, Covid-19 and influenza differ significantly in terms of public health. The SARS-CoV-2 virus spreads more rapidly than the influenza virus and can cause much more severe illness. The symptoms of Covid-19 also last longer, increasing the likelihood of infecting more people.
Covid-19 has many differences compared to seasonal influenza, making the coexistence with the disease not the same. (Image: AFP).
Analyses based on influenza outbreaks show that the average transmission rate of this virus is 1.28, meaning that 4 people with the flu can transmit the virus to an additional 5 people.
In contrast, SARS-CoV-2 spreads faster, especially with the Delta variant. The transmission rate of the Delta variant is 7.0. In the absence of vaccination or other intervention measures, one infected person can spread the virus to 7 others.
Covid-19 has a higher mortality rate than influenza. Statistics indicate that seasonal influenza has killed approximately 44,505 people in the UK over three flu seasons from 2015-2016 to 2017-2018, which is equivalent to the number of deaths from Covid-19 in just the first 9 weeks of 2021.
Seasonal flu has existed long enough for natural immunity from infections and previous vaccinations to likely reduce cases and fatalities. Meanwhile, Covid-19 vaccines effectively reduce severe cases and deaths but do not completely eliminate the risk of virus infection.
In the UK, the Covid-19 vaccines currently in use, such as AstraZeneca and Pfizer, have reduced the risk of hospitalization due to Covid-19 by over 90%. The vaccination program has also significantly reduced the number of deaths, falling below 20 cases per day in the past week.
However, due to the differences between Covid-19 and influenza, even with vaccines, the ability to coexist with seasonal flu does not imply that society can easily adapt in the same way to Covid-19.
Every year, a global surveillance network detects which influenza variants are circulating and most likely to pose a threat in the following season to develop annual flu vaccines, which are then widely administered. Throughout the flu season, public health agencies report the number of infections and update medical care guidelines. Nevertheless, the number of deaths due to influenza in a typical year is still quite significant, placing considerable strain on the healthcare system.
In contrast, there is currently no global surveillance system in place for Covid-19.
For healthcare services, coexisting with Covid-19 also means learning to endure a double wave—Covid-19 alongside seasonal flu—every winter.
