Coronavirus: Co-infection with influenza may accelerate the replication of the pathogen that causes Covid-19, studies say

Hong Kong, October 26 (SCMP): Coinfection with influenza resulted in up to 10,000-fold increase Coronavirus Replication in human cells in laboratory tests, according to a new study by Chinese scientists.

Laboratory experiments have shown that influenza A virus can alter the structure of a wide variety of human cells within hours of infection. According to a paper posted on the preprint website Biorxiv.org on Wednesday, the SARS-CoV-2 virus can take advantage of these changes to easily invade cells and propagate more efficiently. ..

“The fusion of the flu season in the Northern Hemisphere with the Covid-19 pandemic could pose a serious threat to public health,” said a team led by Professor XuKe of the State Virology Institute at Wuhan University. ..

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In China, people are being encouraged to be vaccinated against the flu by the end of October. Influenza and Covid-19 share some symptoms that health officials fear not only complicate the diagnosis, but can also cause panic.

However, some mainland media reports are lacking in influenza vaccination, forcing some to resort to overpriced alternatives that have not been tested in the black market.

Xu’s team conducted tests on different human cells from different parts of the body. In addition to influenza A virus, other pathogens such as rhinovirus, Sendai virus, and enterovirus were also included in the experiment.

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After exposing cells pre-infected with these viruses to the new coronavirus, researchers found that only influenza A virus could exacerbate the infection.

This occurred in almost all human cells, but the most vulnerable were from the surface of the lung, with a 1,000-10,000-fold increase in coronavirus replication, depending on the intensity of influenza infection.

They repeated the experiment with mice and the results were similar.

“Pre-infection with influenza A virus provided the first evidence that it strongly promoted SARS-CoV-2 virus invasion and infectivity in co-infected cells and animals,” the study said.

Earlier this year, in Wuhan, the city of central China where the coronavirus was first detected at the end of last year, doctors found many cases of coinfection in critically ill patients in the intensive care unit.

Sun Tieying, a doctor at Beijing Hospital who went to Wuhan to help fight the pandemic, said in a May newspaper report that 20 out of 50 Covid-19 patients in the ward had the flu.

Health officials in other countries have issued similar warnings about the dangers of co-circulation of different virus strains. Dr. Robert Redfield, director of the US Centers for Disease Control and Prevention, said in August that the United States could face “the worst fall ever from a public health standpoint.”

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In the Xu study, patients infected with influenza A virus may have more receptors on the cell membrane to bind to the coronavirus. Researchers have observed a dramatic increase in angiotensin converting enzyme 2 (ACE2) expression in influenza-infected cells.

ACE2 is a protein that can bind to the coronavirus spike protein. Organs high in ACE-2-expressing cells can be more damaged.

In their experiments, researchers used different versions of the influenza A virus, including H1N1 and H2N3. The former caused a pandemic that killed up to 50 million people worldwide in 1918, and the latter, also known as the Hong Kong flu, caused an outbreak in 1968 that killed an estimated 1 to 4 million people. ..

All influenza strains were found to function with the SARS-CoV-2 virus, but the mechanism by which replication was promoted remained unclear, the researchers said.

However, they have identified a gene segment of influenza A virus that may play an important role in helping coronavirus copying within infected cells.

“Social distance and wearing masks are beneficial in protecting people from either or both attacks [viruses]”The study said. -South China Morning Post