Gosh! huge subject. The answer is yes there is, but it depends on how badly your horse is affected.
Apparently (vet advice) its the horses with the worse sweet itch that the injections can help more. Mine has "mild to moderate" sweet itch and my (very honest) vet said that it probably wouldn't have much effect in his case. They are not cheap!!! He said that the vast proportion of clients in our practice had not signed up for future courses. You have to start the injections, if you're gonna do it, way before the sweet itch season starts anyway, so it would be too late for this year.
I've tried all the gunk that you can buy in the way of feed supplements and my feelings are basically save you money! However, the think that I did use was (cheap and cheerful) Marmite sandwiches which apparently are a tried and trusted way of getting Brewers Yeast, which is the active ingredient, into the horse. Also apparently Linseed is a good thing.
Pig oil and sulpher has been recommended as well; you have to mix it up and then apply to the area's which are sore; but don't use pig oil on its own in the summer as it might "fry" your poor horse! I've found this a really good cheap and cheerful remedy for feather mite and it leaves the coat lovely and smooth (not saddle area!!!) so the midges don't like to settle on it.
Other things are to get a sweet-itch rug: I bought a Pagony which is the cheapy version of the Boett and found it frankly useless and downright dangerous as the horse somehow got himself tied up in it and ripped it. I've used the Premier Equine hoody sweetitch rug and the Rambo hoody is brill - not cheap but does the job. Also the Pessoa sweet itch hoody.
You really need to talk to your vet; but beware coz most vets will probably talk you into the de-sensitisation coz its mega-bucks for them. My vet is honest thankfully, so saved me some money, bless him.
I'm trying my horse on the new Eos capsules which he's having once a week at the mo - again not cheap but they are recommended by the National Sweet Itch centre very highly, so I thought to give them a go. So we'll have to see. They don't promise a cure as such, but they do say that it might help significantly alongside other precautionary measures like covering up and stabling at dawn and dusk, the usual sweet-itch precautions.
not sure what happened to OP with the pagony rug getting her horse wrapped up in it but i think its worth its weight in gold for my horse ask for advice for the size you require re; usual rug size or smaller.
the pessoa, premier and rambo rugs dont cover all the bits that get bitten in fact the rambo one someone has got on my yard doesnt even cover half the horses neck when he's grazing ! you deffo need the hoody types !!
as for the jabs ive been told its a bit hit and miss and darn expensive !!
shes been on immune therpy for a few years now but that and a snuggys rug means she can now live out 24/7 as her allergys were so bad
but it wasnt just the midges causing her problems she allergic to loads of grass pollens black ants, fire ants and loads of other things including a chemical in a non natural fly spray and all cereals and sugar beet
shes now a very happy dartmoor and the immune therpy injections have change her life
i did have a boett but shes needed an udder pad as she was kicking he self raw but before the jab would rub like mad even rugged and her eyes would swell and face would get very sore and her whole body would be rubbed raw
I will second the marmite sandwiches. This year I have sprayed Avon Skin So Soft (next to nothing from ebay!) or a mix of TCP and water (half small bottle of TCP w about 1 litre of water) on tails and manes morning and evening and so far we are displaying lovely, silky un-rubbed tails. Happy days!
I always try the cheap suggestions first before I go for expensive ones!!
Have to say, not sure about the sulphure and pig oil (I've been told to use udder cream and sulphur for mud fever before and it cured him completely but never heard of it for sweet itch!).
My horse had sweetitch, she went to Liphook for allergy testing and the vet there said the sweetitch vaccine was very crude and did not work well, he recommened a Boett rug, which I used with some success. However this year I tried a new product called Cavalesse which is a Vit B supplement that you give them every day at roughly the same time. It costs £70 for 3 months, you are supposed to give it at the start of the midge season for the best effect. I can only say that it really helped my horse and made a huge difference. She was much less itchy after starting that treatment. You need to buy it from the vet, or online from veterinary suppliers.
Mine get SI but I could sell them tomorrow saying they didn't as there are no signs - BUT this is due to my management.
They live out May to October. The field is taped off so they cannot rub. They wear snuggy bodies with the sheath/udder covers when out apart from about one hour a day whilst I am doing field jobs so they can have a good groom at each other.
I don't use the hoods unless it is very midgy as they can rub the manes if left on 24 x 7 for weeks on end and I show. What I do is put a mix of essential oils, avon skin so soft and dettol mixed with water on twice a day. I also use megatek on the manes and tails which also seems to repel midges as well as keep the hair growing fast and in very healthy condition.
They are fed brewers yeast, linseed and I have found a very effective supplement, clivers for their skin health.
If they have to come in, they wear a hood and have cotton tail guards on to stop them rubbing badly and I try to avoid having them in if I can.
However tie them up near a wall, and they will have a good rub given the chance, hence I know I can control but not cure the problem. Mine have full manes and tails and since I have the covers, no more rubbed bellys and sore boobs and sheath.