using tail to follow a log and execute a command instantly? Only seems to work by starting a new line

I am trying to figure out a command which will enable me to read a log file in real time and execute a command when the string matches? I am using logkeys and trying to make it when I type a word it immediately triggers a command. This script works, but only when I press enter (start a newline) does it execute, and it seems anything I have found online also requires the press of the enter key to work. Is there a way to get around this somehow?

/bin/bash

echo Waiting...
string='test'
tail /path/to/logfile -n0 -f | while read line; do
        if [[ $line =~ $string ]]; then
                echo "hello"
        fi
done