Using Bash Less and Grep together

Question

I have been trying to follow and filter an log file using

less +F +G /var/log/messages |  grep -v -f ignoredwords.txt | grep -f words.txt

but it seems the file is not continoulsy read and the operation stops once the whole file is read

i have tried using same with tail -f but that seems to be skipping alot of lines any suggestion to improve