Context :

Aims : The aim of the project is to improve our knowledge on the multiplicity of planet-host stars at wide physical separations .

Methods : We cross-matched approximately 6200 square degree area of the Southern sky imaged by the Visible Infrared Survey Telescope for Astronomy ( VISTA ) Hemisphere Survey ( VHS ) with the Two Micron All Sky Survey ( 2MASS ) to look for wide common proper motion companions to known planet-host stars .
We complemented our astrometric search with photometric criteria .

Results : We confirmed spectroscopically the co-moving nature of seven sources out of 16 companion candidates and discarded eight , while the remaining one stays as a candidate .
Among these new wide companions to planet-host stars , we discovered a T4.5 dwarf companion at 6.3 arcmin ( \sim 9000 au ) from HIP 70849 , a K7V star which hosts a 9 Jupiter mass planet with an eccentric orbit .
We also report two new stellar M dwarf companions to one G and one metal-rich K star .
We infer stellar and substellar binary frequencies for our complete sample of 37 targets of 5.4 \pm 3.8 % and 2.7 \pm 2.7 % ( 1 \sigma confidence level ) , respectively , for projected physical separations larger than \sim 60–160 au assuming the range of distances of planet-host stars ( 24–75 pc ) .
These values are comparable to the frequencies of non planet-host stars .
We find that the period-eccentricity trend holds with a lack of multiple systems with planets at large eccentricities ( e > 0.2 ) for periods less than 40 days .
However , the lack of planets more massive than 2.5 Jupiter masses and short periods ( < 40 days ) orbiting single stars is not so obvious due to recent discoveries by ground-based transit surveys and space missions .

Conclusions :