Yale Study Discover That Common Cold Caused By Rhinovirus Combats Influenza And Needs To Be Studied If It Could Do The Same For COVID-19
: Researchers from Yale University School of Medicine have discovered that the Rhinovirus which causes most of the common colds can prevent the flu virus from infecting airways by jumpstarting the body's antiviral defenses.
The study findings help answer a the strange phenomena surrounding the 2009 H1N1 swine flu pandemic in which an expected surge in swine flu cases never materialized in Europe during the fall, a period when the common cold becomes widespread.
The study findings were published in the journal: Lancet Microbe. https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30114-2/fulltext#%20
The study team led by Dr Ellen Foxman studied three years of clinical data from more than 13,000 patients seen at Yale New Haven Hospital with symptoms of respiratory infection.
The team discovered that even during months when both viruses were active, if the common cold virus was present, the flu virus was not.
Between July 1, 2016, and June 30, 2019, examination of 8284 respiratory samples positive for either rhinovirus (n=3821) or IAV (n=4463) by any test method was used to establish Nov 1 to March 1 as the period of peak virus co-circulation.
After filtering for samples within this time frame meeting the inclusion criteria (n=13 707), there were 989 (7·2%) rhinovirus and 922 (6·7%) IAV detections, with a significantly lower than expected odds of co-detection (odds ratio 0·16, 95% CI 0·09–0·28).
It was found that rhinovirus infection of cell cultures induced ISG expression and protected against IAV infection 3 days later, resulting in an approximate 50 000-fold decrease in IAV H1N1pdm09 viral RNA on day 5 post-rhinovirus inoculations. Blocking the interferon response restored IAV replication following rhinovirus infection.
Dr Foxman, an Assistant Professor of laboratory medicine and immunobiology and senior author of the study told Thailand Medical News, "When we looked at the data, it became clear that very few people had both viruses at the same time."
Dr Foxman stressed that scientists do not know whether the annual seasonal spread of the common cold virus will have a similar impact on infection rates of those exposed to the coronavirus that causes COVID-19.
She added, "It is impossible to predict how two viruses will interact without doing the research.”
In order to test how the rhinovirus and the influenza virus interact, Dr Foxman's lab created human airway tissue from stem cells that give rise to epithelial cells, which line the airways of the lung and are a chief target of respiratory viruses.
The study team found that after the tissue had been exposed to rhinovirus, the influenza virus was unable to infect the tissue.
Dr Foxman explained, "The antiviral defenses were already turned on before the flu virus arrived.”
The study team said that the presence of rhinovirus triggered production of the antiviral agent interferon, which is part of the early immune system response to invasion of pathogens.
Dr Foxman said that the effect lasted for at least five days.
Dr Foxman said her lab has begun to study whether introduction of the cold virus before infection by the COVID-19 virus offers a similar type of protection.
Hopefully as the flu season approaches, the already strained public health system may have a surprising ally the common cold virus ie the rhinovirus.
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