วัคซีนที่คิดค้นขึ้นเป็นพิเศษเพื่อช่วยยุติโปลิโอ
The first new polio vaccines in 50 years are less likely to mutate into a dangerous form that causes disease.
The first new polio vaccines in 50 years are less likely to mutate into a dangerous form that causes disease.
