This project did not find a link between cytomegalovirus and brain tumors. However, they sensationalized the headline by saying brain tumors are not caused by viruses then went on to say antiviral therapy is misguided.
This is a very controversial subject. I have seen people who did well with antiviral drugs. Some researchers reported that all or almost all of the gbm samples they tested had the virus. It is possible that the virus does not cause the tumor but allows it to become more malignant and to evade the immune system. If true, then antivirals - or even vaccines against cytomegalovirus, make a lot of sense.
There has been a study on human trials of antivirals. Unfortunately the study was designed poorly. It had good results, but poorly designed studies are not considered proof that something works. What is needed is a better designed study. It may be impossible to do a gold standard phase 3 randomized double blinded trial because the drugs are expensive and the companies that make them are not interested in supporting brain tumor trials, so we may have to do it on our own in a virtual way. I am working on that.