Announcements about the about the forthcoming vaccinations against Covid-19 are exciting and welcome, but it's not good news for everyone. Some people who are allergic to certain antibiotics can't have flu or shingles jabs for example, because they could cause a potentially fatal allergic reaction. Neomycin, in particular, is used in the manufacture of vaccinations, leaving tiny traces of it in a jab which can be enough to trigger the allergic response.
Fortunately not all vaccines are made with neomycin; for example the adult pneumonia vaccine used in does not contain it. And happily, the latest Covid vaccine to be unveiled, developed by Oxford University, does not contain neomycin, so could be safe for someone with an allergy to it.