cough. a brutal cough that can last for months. a potentially fatal illness especially for babies and young children who haven't had a chance to get all their shots yet. >> they may have spells of apnea where they stop breathing. one to two out of a hundred can die from this. >> reporter: 16 states are seeing an increase in cases compared to this time last year. more than 2,000 cases so far in texas alone. claiming the lives of two babies. the state is on course to have its worst whooping cough outbreak in over 50 years. officials this week issuing a health alert warning texans that vaccinations are vital. but the effectiveness of the whooping cough vaccine fades quickly. by age 11 only seven out of ten kids are still fully protected. that's why the centers for disease control recommends a booster shot for preteens to protect themselves and any babies they could unwittingly