Trying add a repeated check of a variable. Could someone help?

So I'm trying to add a check that always sees whether _G.score is more than a certain integer. This is what I've put so far:

_G.score = 0

while true do
	if _G.score < 5 then
		 game.ReplicatedStorage.ChangeChar:FireServer(game.ReplicatedStorage.Bacteria)
	end
	
	if _G.score > 5 and _G.score < 15 then
		game.ReplicatedStorage.ChangeChar:FireServer(game.ReplicatedStorage.Virus)
	end
	wait(0.5)
end

However, this causes it to fire the first piece of code repeatedly rather than just check if it's more than 5 and if it is then FireServer.