Ahead of winter in the northern hemisphere, scientists have warned that seasonal influenza may bring more challenges to the prevention and control of the new pandemic. Could seasonal influenza affect the severity of the Covid-19 pandemic?
Is it necessary to increase flu vaccination in winter?
There’s a lot of debate about this.
On February 18 (local time), A Research team from Wuhan University published A Research paper titled “Coinfection with influenza A virus enhances SARS-CoV-2 Infectivity” in the international academic journal Cell Research.
Can influenza virus and novel coronavirus co-infect in individuals?
What is the effect of influenza virus infection on novel coronavirus infection?
Will co-infection of the two viruses cause more serious illness?
The research team came up with answers around these questions.
Prof. Ke Xu, State Key Laboratory of Virology and College of Life Sciences, Wuhan University, and Prof. Ke Lan, Director of State Key Laboratory of Virology and College of Life Sciences, Wuhan University are the co-corresponding authors.
Cell Research is a Chinese-grown international journal with the highest impact factor in life science journals in the Asia-Pacific region.
Novel coronavirus can promote infection by influenza virus for the first time, and by building a mouse model of co-infection between influenza virus and novel coronavirus, we found that the co-infection caused more serious disease in mice. In this paper, we also studied the molecular mechanism of influenza virus promoting novel coronavirus infection and virulence.
The results showed that the co-infection of the two viruses was like “pouring oil on the fire”, which enhanced the infectiousness of novel coronavirus and then led to more serious diseases. The study provided a scientific basis for further attention and prevention and control of the co-infection of the two viruses.
Influenza virus preinfection significantly promoted the ability of new pseudoviruses and live viruses to infect in cellular models.
According to the official website of wuhan university to the research, the report said the team first, each in new crown false virus and live virus and influenza virus type a (H1N1 and H3N2 and b influenza virus) infection and found infected with influenza virus can significantly promote the advance will be coronavirus invasion and copy, this phenomenon in a variety of human respiratory tract cells and human cells are present in the lung tissue, can make originally not infection will be coronavirus cells to become completely susceptible cells, patients with two viruses infection may result in total, virus attacks on more cells and tissues in the body.
Influenza co-infection with Novel Coronavirus caused more severe pulmonary pathological damage and higher Novel Coronavirus load in ACE2 transgenic mice.
In novel coronavirus receptor human ACE2 transgenic mice, influenza co-infection with novel coronavirus caused more severe pulmonary pathological damage and higher novel coronavirus load.
The team then focused on Novel coronavirus’s invasion of the key receptor ACE2.
The experimental results showed that the expression level of ACE2 was slightly up-regulated (2-3 times) by influenza infection alone, while the expression level of ACE2 was strongly up-regulated (about 20 times) by influenza co-infection with new crown.
It is suggested that influenza virus infection may aggravate novel coronavirus infection by activating ACE2 expression and promoting the subsequent accelerated expression process.
We also found that ACE2 was not regulated by interferon, suggesting that the immune response against influenza virus could not protect the individual against novel coronavirus.
Therefore, immunity against other viruses cannot be assumed to be obtained from ordinary influenza.
Influenza virus infection aggravates novel coronavirus infection by activating ACE2 expression.
The study also found that other common respiratory viruses such as parainfluenza virus, respiratory syncytial virus, rhinovirus and so on do not have the ability to promote novel coronavirus infection.
The team therefore believes that influenza viruses are a top priority in co-infection prevention and control.
The study suggests that scientific surveillance and prevention should be carried out for winter influenza and NCSTA epidemics, and the public should be vaccinated against influenza or NCSTA to reduce the risk of co-infection.
The study also highlights that the development of a new generation of broad-spectrum antiviral drugs targeting more than one virus is the direction of development in the treatment of co-infectious diseases.