There was some fighting over movie rights why 28 Months Later has been in the limbo for 15 years. Director of the first and the producer Danny Boyle has stated many times that he wants to do it and direct it. I think recently there was some development in the situation because there is really high demand for the sequel. These are good horror movies.
Long time ago the plot was to make it happen in Russia and the orginal star Cillian Murphy returning.