Flea treatment Comfortis or injection?

[Liz]

Covenia is the the injectable treatment and we have been using it for the last thirty years on ours as we had a lot of ferals and its so much easier never had any issues with it and totally recommend it

[Desley (booktigger)]

I've only used the tablets, but when I used them, each tablet was only for 2kg, so the choice was either 2.5 tablets for my 5ish kg cat, or half a dog one, I've not used it on a cat since so don't know if that has improved, he had a reaction to spot ons, so we had to use an alternative, I personally prefer spot ons to the tablets.

[cathycat]

Hi all.
My cat Alfie has just recovered from a mild dose of cat flu (he is vaccinated). He's well but it has left him with sensitive eyes. I had delayed his Advocate spot on flea treatment this time for 3 weeks while he was recovering. The delay has meant fleas have emerged so I decided I really needed to give him his Advocate but because his eyes are sensitive he freaked out (the smell of it?) and I don't think any treatment actually made contact with him but I'm not sure.
 I don't want to use it again on him in the future as it really upset him so I'm looking into either Comfortis tablets or the injection that lasts 6 months, I'd love some feedback on either of these if anyone has experience.
Do I need to wait a month before giving him either of these because I'm not sure if any Advocate made contact with him?
Thanks