I have had ET for 12 years + and am currently on a fairly high dose of Hydrea. I live in Australia but each year travel to the UK for several months. After having stable platelets for several months prior to my flight, I find they shoot up quite considerably when I have my blood tested in the UK. I wonder if it is the long flight or the fact for the past two years, I have had a flu vaccination approx 2 weeks before I left Australia. Could it be the stress involved in flying or just a reaction to the vaccine? Anyone any ideas please?