21.   The main side effects were low fever, irritability and decreased appetite within five days of the first vaccine doses.

22.   British pharmaceuticals group SmithKline Beecham said Thursday that its Havrix product, the first vaccine against hepatitis A, had been approved by Chinese authorities.

23.   Jonas Salk, who developed the first vaccine to prevent polio, died Friday, a spokeswoman for the Salk Institute said.

24.   Jonas Salk, who tamed the scourge of polio by developing the first vaccine against the dread disease, died Friday, a spokeswoman for the Salk Institute said.