Vick’s?

Why can’t a baby under 3 months use baby Vick’s or be under 10lbs to use the Vick’s humidifier? My daughter is congested and she’s not yet 2months old and 6lbs 11oz.. I have the Vick’s humidifier but it was not use the Vick’s in it if under 10lbs, and we have been sucking out her nose every 1hour or more but it’s not helping.. they say it’s just viral upper respiratory infection and they can’t do anything and is checking her for whooping cough as well just waiting for the test results to come back on that