This can cause low levels of red and white blood cells and platelets. • A type of anaemia where your red and white blood cells and platelets are reduced. • An infection in your urine. • A viral infection causing cold sores (herpes). • Bleeding gums, bleeding in the stomach or gut, bleeding from around your back passage due to piles (haemorrhoidal haemorrhage), bleeding in your eye, bleeding under your skin, or into your skin (haematoma). • Blood in your urine. • Ulcers of your mouth or tongue. • Changes to your skin at the injection site.