My daughter developed chicken pox a few days ago despite her getting the vaccine:o . I took her to the er due to dehydration and severe right abdominal pain. The right sided pain was due to the virus and she was treated with fluids and started on a antiviral drug to shorten the length of this virus. The er reported this to the cdc. They said they are seeing many kids having severe breakthroughs despite the vaccine. Has anyone heard of this and why? She is getting better but gosh is she one sick little girl. Thank you for any replies.