We'll start by pointing to an article written some years ago but which is still relevant today...

Whilst there are dangers, the authors point is that manufacturing a new pathogen that could survive in the wild is a difficult process.

Synthetic biology, on the whole, has reaped benefits for humanity as evidenced in the following article which also urges caution at the same time...

It appears that synthetic biology may be more helpful than harmful and we could not find any articles suggesting that synthetic biology could herald an extinction level event; rather, that it may stop or even reverse one...