Flu Shots and Hydroxyurea

My husband was diagnosed with ET eight years ago and has been on 1000mg of Hydrea for the past ten months. We hasn't had side effects other than occasional mouth sores, and his platelets have gone from over 800 to under 400. My question is, to this community, is it possible to get a flu shot?

We run a yacht and are subject to a lot of people and germs, so it would be great if he could. Thanks to all!

 Flu shot has been found, by independent studies, to be effective in less than 10% of people who receive it

Maintaining year round Vit D level of 50ng/ml or greater has been found to prevent flu in vast majority of people

The flu bug only shows itself in the winter? No, it's around all year long. It's not a coincidence that the 'flu season' occurs during the time of year when Vit D production isn't possible, due to the angle of the sun. And people's Vit D levels during 'flu season' are roughly 1/2 what they are in the summer