Viral Interference

Subject : Science and technology

Section : Health

Concept :

Three years into the pandemic, COVID-19 is still going strong, causing wave after wave as case numbers soar, subside, then ascend again.
Now in addition to covid, there is a return of flu (absent during the pandemic) plus respiratory syncytial virus (RSV), creating a “tripledemic.”
The surges in these old foes were particularly striking because flu and RSV all but disappeared during the first two winters of the pandemic. Even more surprising, one particular version of the flu may have gone extinct during the early Covid pandemic.
Scholar Webby thinks that the factor that may have kept them at bay while Covid raged. It’s called viral interference, and it simply means that the presence of one virus can block another.

Viral interference

Viral interference is a phenomenon for which a cell infected by a virus becomes resistant toward a second outcoming infection by a superinfectant virus.
Multiple respiratory viruses can concurrently or sequentially infect the respiratory tract and lead to virus‒virus interactions.
Infection by a first virus could enhance or reduce infection and replication of a second virus, resulting in positive (additive or synergistic) or negative (antagonistic) interaction.
The concept of viral interference has been demonstrated at the cellular, host, and population levels.
The mechanisms involved in viral interference have been evaluated in differentiated airway epithelial cells and in animal models susceptible to the respiratory viruses of interest.
A likely mechanism is the interferon response that could confer a temporary nonspecific immunity to the host.
Even though other mechanisms are known, it can be assumed that most cases of viral interference occurring in natural conditions are mediated by interferon.
It is a low molecular weight protein produced by the infected cell in response to a stimulus provided by viral nucleic acid(s).
The interferon produced by a cell can migrate to other cells not yet involved by the spreading infection, transmitting to them the antiviral-resistant state.