Why don't the CDC researchers keep in touch by radio or wi-fi VOIP?
They all could have headsets and use smartphone's built-in wi-fi/hotspot technology to use the stations wi-fi for person to person communications or even use regular radio based walkie-talkies, but are not. The reason why they are not using this simple and expected technology is unknown. In contrast, the Ilaria Corp COO Sutton is seen using a headset communicator of unknown type to communicate with her security forces.
Is HELIX a show about zombies?
Not exactly. HELIX is a sci-fi thriller about the outbreak of two unknown viral strains. While the first strain (NARVIK A) simply kills the host, the second strain (NARVIK B) seem to take control of its host. Just like any other virus, its primal objective is to spread. By literally controlling the host's body, the behavior of the host does resemble zombie behavior during the first stages of infection. The infected (called "vectors") do not feed, are quicker and much more agile than humans and spread the virus with a black substance they vomit, which seems identical to their blood. As the infection becomes older, the virus shows signs of intelligence. Vectors can cooperate under the guidance of an alpha vector (the oldest infected) and can use intelligent tactics to lure humans.
NARVIK is the name of two mysterious viral strains.NARVIK A was made by ARCTIC BIOSYSTEMS for ILARIA corporation. One of ILARIA's board members, Constance, mentioned that they want the virus to reduce Earth's population and Hiroshi added "to rule" the rest, probably with ILARIA's power and owned resources after the pandemic period.NARVIK B seems to be Hiroshi Hatake's creation and it presumably is a mutated strain of NARVIK A. Constance mentioned that NARVIK B is "the Willis hypothesis". Willis hypothesis' main thesis implies that new forms arise by mutation rather than natural selection. It seems Hiroshi wanted to create a virus to "evolute" humanity, possibly because he thinks that ILARIA may as well exterminate all of humanity to keep the whole world for the "immortals". Constance added that "ILARIA said NO then, nothing has changed". That means Hiroshi's fears may have a solid ground.