Omega-3 Fatty Acids and COVID
The most important omega-3 fatty acids are EPA and DHA. These are found in small amounts in the fat of land animals, especially egg yolks, and especially when those animals are raised on pasture, and in large amounts in fish, fish liver oil, and cod liver oil. Vegan supplements contain these fatty acids extracted from algae.
As covered here, here, and here, EPA can act similar to an NSAID (a type of over-the-counter anti-inflammatory drug) by obstructing the inflammatory process. This obstruction tends to prevent inflammation from reaching as high a peak, but also prevents it from fully resolving. DHA, by contrast, readily contributes to the active resolution of inflammation. However, aspirin is unique among NSAIDs in that it can jumpstart the resolution of inflammation, and it can even help EPA drive the resolution of inflammation just like DHA does on its own. Furthermore, bacteria can enhance the ability of EPA to contribute to the resolution of inflammation, so there might be an interaction between EPA and probiotics worth exploring.