Considering most deaths (by animals) are caused by mosquitos, it's a fair risk to take imo. Glad they were successfull. Hopefully this will not cause the creation of more dangerous viruses in the end.
When infected with Wolbachia, the mosquitoes are much less likely to transmit diseases such as dengue and Zika, because the bacteria compete with these viruses. The insects also pass the bacteria on to their offspring. Researchers hope that the modified mosquitoes will interbreed with the wild population wherever they are released, and that the number of mosquitoes with Wolbachia will eventually surpass that of mosquitoes without it.
I was not familiar with this method. Seems like a neat idea.