An interferon blocker might help treat patients with severe Covid-19 infection, a local health expert said.

His claim is the opposite of the opinion of many researchers who are testing interferons as a treatment for Covid-19 in ongoing trials.

Interferons are proteins made by cells in response to infection, suppressing viral infection, and proliferation.

Shin Eui-cheol, a professor at the KAIST Graduate School of Medical Science and Engineering, said inhibiting interferons might help treat seriously ill Covid-19 patients, at a YouTube show "Corona Fighters Live" on Friday.

Shin Eui-cheol, a professor at the KAIST Graduate School of Medical Science and Engineering, said only severe Covid-19 patients showed strong interferon responses, at a YouTube show "Corona Fighters Live" on Friday.

He recently published his study in Science Immunology, suggesting that an interferon inhibitor could be one of the new treatment options for Covid-19 patients with serious symptoms.

According to Shin, Covid-19 patients, regardless of the severity of symptoms, showed tumor necrosis factor (TNF), one of the cytokines signaling inflammation in the immune cells, interleukin-1 (IL-1), and interleukin-6 (IL-6).

In particular, a cytokine reaction called interferon was present only in severe Covid-19 patients, he said.

People tend to say that a cytokine storm causes young Covid-19 patients' death only, not the aged, but this was not true, Shin said.

Regardless of age, Covid-19 deaths result from excessive responses to inflammation, he noted.

He thought TNF, IL-1, and IL-6 levels increased with the severity of symptoms in the past.

However, his latest findings showed that their levels were already high, regardless of the disease's mildness and severity, Shin said.

If interferons go up along with elevated levels of TNF, IL-1, and IL-6, they seem to trigger the severity. That is why he claimed that people might have to suppress interferons, he said.

Shin cited the results of a paper on an experiment on rats injected with the SARS virus.

“When the SARS virus was injected into the rats, they all died. It is advantageous if interferons come out quickly. Still, if they come late when symptoms get severe, they rather caused inflammation,” he said. “When interferons were blocked, rats that almost died recovered in the end.”

In another experiment on rats infected with the MERS virus, using interferons immediately after the MERS infection worked effectively. However, after the rats got seriously sick, treating the rats with interferons led them to die, Shin said.

“It may be the same drug, but it can cause completely different outcomes depending on when you use it,”

Shin raised the possibility that researchers could develop a Covid-19 vaccine targeting a T-cell response in Covid-19 patients with mild symptoms.

Citing papers from the U.S. and Europe, he said people who were never exposed to the Covid-19 virus did not have antibodies but T-cell responses.

Shin said if researchers set a vaccine’s target as a T-cell response, the vaccine’s practical use will be different.

While a neutralizing antibody-targeting vaccine can prevent Covid-19, a T-cell targeting vaccine will allow an infection but hinder its progress.

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