Well, a vaccine isn't really that likely to be effective, as malaria is a parasite, as opposed to a virus. Yes, some vaccines do work on organisms other than viruses, but they typically aren't nearly as effective.Instead of eradicating mosquitoes - which would impact the ecosystem negatively in other ways - we need better malaria treatments for humans. Like, a proper vaccine for example.
Anyway, I don't think there's much reason to believe that significantly reducing the numbers of parasites like mosquitoes has much of a negative impact on the environment directly (though the particular means to reduce the parasites, such as pesticides, may). Regardless, a machine like this wouldn't make a whole lot of difference to mosquito populations anyway. It would reduce the population in the vicinity of the machine, of course, but as long as they have breeding grounds, their numbers will remain quite large.
Most effective means of reducing mosquito populations aim at reducing their breeding grounds. Incidentally, one of the first indications of the housing crisis was an increase in mosquito-borne illness: as people left their homes untended, it left many pools, ponds, and other such breeding grounds untended, and thus ready for the mosquitoes to capitalize on.