Viral labyrinthitis is potentially contagious in that it is an illness spread by viral infection.
However, the responsible virus may not necessarily cause labyrinthitis in each individual who becomes infected with the virus. In other words, one individual may develop predominantly sinus symptoms whereas another may develop predominantly ear symptoms. Why this should be is poorly understood. The mode of viral spread varies but in the case of common viruses responsible for upper respiratory infection, the usual mode is via air-borne secretions. Good handwashing habits are one of the best means of prevention.