Thông tin: Experts met at the WHO headquarters in Geneva in February, 2007, and reported that their work on pandemic influenza vaccine development had achieved encouraging progress. More than 40 clinic trials have been completed or are ongoing. Most have focused on healthy adults. Some companies, after completing safety analyses in adults, have initiated clinical trials in the elderly and in children. All vaccines so far appear to be safe arid well-tolerated in all age groups tested.

Đáp án đúng là C. has appeared to be safe in all age groups tested