# Beneficial and Detrimental Effects of Cytokines during Influenza and COVID-19

## TL;DR

This paper reviews how cytokines can both help and harm during influenza and COVID-19, and suggests a new way to measure their effects.

## Contribution

A new method is proposed to quantify cytokine effects to preserve benefits while reducing harm.

## Key findings

- Cytokines have both beneficial and pathological roles during viral infections.
- High cytokine levels correlate with disease severity in influenza and COVID-19.
- Targeting cytokines during disease presents challenges due to their dual roles.

## Abstract

Cytokines are signaling molecules that play a role in myriad processes, including those occurring during diseases and homeostasis. Their homeostatic function begins during embryogenesis and persists throughout life, including appropriate signaling for the cell and organism death. During viral infections, antiviral cytokines such as interferons and inflammatory cytokines are upregulated. Despite the well-known benefits of these cytokines, their levels often correlate with disease severity, linking them to unfavorable outcomes. In this review, we discuss both the beneficial and pathological functions of cytokines and the potential challenges in separating these two roles. Further, we discuss challenges in targeting these cytokines during disease and propose a new method for quantifying the cytokine effect to limit the pathological consequences while preserving their beneficial effects.