In particular, if true that it 'leaked' ... it's not like other nations are leaking pathogens which kill millions and cause 5 Trillion in destruction. It would literally change the geostrategic equation overnight and be seminal, defining world event certainly bigger than 9/11. On the scale of a WW.
If it was quasi-intentional (this is definitely not true, but since you speculated...) then it would be an act of war and the most damaging attack on the US (and other nations) ever. The US and the world would have to go to war with China over this. (Again this surely is not the case).
All while the US/EU/Rest of Word 'get better' at the above.