Forget all the fancy meds and creams that the manufacturers WANT you to buy, its a virus like a cold. good hygine to reduce chance of cross contamination is all you need.
Twice a day rub there little noses with a sponge covered in neat Hibiscrub (its what surgeons scrub up with) its £7 for 500ml and will last you ages. you will reduce the inflamation, risk of infection and risk of pasing it on.
Hibiscrub should be in every small holders box, you can use it on almost any wound, skin condition, teats and udders and you can use it on yourself before any assited births and on them after. good for umbilicals aswell, especialy if you have any ewes/cows who take issue with iodene(excessive licking to remove the smell causing haemoraging)
Plus next year you can vaccinate them first, save yourself the hassle