If you have the data to back this up that the L Strain is the killer and the S Strain is benign.
Spread the S strain if it provides immunity against the L.
(If you are not already attempting to do this.)
Although the L type (∼70%) is more prevalent than the S type (∼30%), the S type was found to be the ancestral version. Whereas the L type was more prevalent in the early stages of the outbreak in Wuhan, the frequency of the L type decreased after early January 2020. Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly. On the other hand, the S type, which is evolutionarily older and less aggressive, might have increased in relative frequency due to relatively weaker selective pressure.
https://academic.oup.com/nsr/advance-article/doi/10.1093/nsr/nwaa036/5775463