Richard Knox

Forty-seven-year-old Celeste Corcoran is propped up in her hospital bed. In a nearby window is a forest of blooming white orchids from well-wishers. On the opposite wall, a big banner proclaims "Corcoran Strong."

She's recalling how thrilled she was to be near the finish line of the Boston Marathon, waiting for her sister Carmen Accabo to run by. "I just remember standing there, wanting to be as close as I could to catch her," Corcoran says. "I really just needed to see her face."

The largest current study of an AIDS vaccine, involving 2,500 people, is being stopped.

After an oversight committee took a preliminary peek at the results this past Monday, they concluded there was no way the study would show that the vaccine prevents HIV infection.

Nor would the vaccine suppress the wily virus among people who get infected despite being vaccinated.

An international dream team of flu experts assembled in China today.

Underscoring the urgency that public health agencies feel about the emergence of a new kind of bird flu, the team is headed by Dr. Keiji Fukuda, the World Health Organization's top influenza scientist.

Before he left Geneva, Fukuda explained the wide-open nature of the investigation in an interview with NPR.

Boston hospitals always staff up their emergency rooms on Marathon Day to care for runners with cramps, dehydration and the occasional heart attack.

But Monday, those hospitals suddenly found themselves with more than 100 traumatized patients — many of them with the kinds of injuries seen more often on a battlefield than a marathon.

Like most big-city hospitals these days, Tufts Medical Center runs regular disaster drills, featuring simulated patients smeared with fake blood.

A precious package arrived at the Centers for Disease Control and Prevention last Thursday afternoon.

Inside, packed in dry ice to keep it frozen, was a vial containing millions of viruses derived from a 35-year-old Chinese housewife who died last Tuesday of respiratory and kidney failure.