Yes, Virginia, reinfection happens -- and it spells bad news for vaccines. That's how the media played the Ballad of Patient AC-06, presented by Harvard University's Bruce Walker at the XIV International Conference on AIDS in Barcelona. Yet again, we mortals are left to sort hype from the true medical meaning.

According to Newsday's Laurie Garrett (whose story led with a characteristically doomy "Grim new findings that put a successful AIDS vaccine even further off on the horizon..."), Walker elicited "cursing and gasping" when he related the tale of a gay HIV positive Boston man in his STI (structured treatment interruption) study who, during unprotected sex, was apparently reinfected (or "superinfected") with a second shot of HIV that made him quickly lose the immune control he had exhibited for nearly a year after his second round off meds. Even more troubling was the fact that the second virus differed by a mere 12 percent from the first. The darkest implication? The ability of such slight variations in HIV to spoil immune control could seriously set back most HIV vaccines in development.

"Bruce, this is terrible news!" top French researcher Brigitte Autran exclaimed, succeeding Walker at the podium. But how terrible? Many among the alarmed AIDSerati audience regained their composure when button-holed by the press. "Without a doubt, this is not a bust for vaccine research," said Walker's STI colleague Todd Allen, PhD. Emilio Emini, PhD, who heads Merck's high-stakes vaccine initiative, played it all down further, saying that AC-06 only joins a handful of other cases in showing that reinfection can happen, not that it regularly does. Plus, said Emini, "You can't compare the immune response in an infected person, which is inherently impaired, to that in a negative person who gets immunized."

There Walker concurred: "You can't make the assumption from the data I presented that a vaccine won't work," he said. "I maintain optimism about a vaccine -- certainly more [so] than the press reports seem to indicate." Calling his paper's implications for vax research "overinterpreted," he said he wanted most to stress its "public health message: Superinfection is absolutely possible."

But in an e-mail to POZ, Garrett stood by her story's portrait of a usually hype-proof audience deeply shaken: "I was stunned by...the quality of [Walker's] work and its results.... I felt every single word out of...Walker's mouth that morning mattered deeply...for this epidemic. And...those sentiments were echoed by the prestigious group of immunologists seated around me."

Such as? NIH AIDS vaccine-program head Margaret Johnston, PhD, and International AIDS Vaccine Initiative (IAVI) research head Wayne Koff, PhD, whom Garrett said were initially "very, very upset" about the paper, but "have both subsequently toned down." Similarly, in The Wall Street Journal, Mark Schoofs reported vax-research veteran Ronald Desrosiers, PhD, of Harvard calling the case "a huge blow to vaccine development," and Cornell's John Moore, PhD, calling it "extremely scary." (Moore passed on POZ's invite to elaborate.)

Indeed, the dismayed chorus from his peers seemed so at odds with Walker's own words to POZ that it begs the question: Did Merck or others who've staked big bucks on vaccines press him to play down AC-06's gloomy vaccine implications?

Emini wouldn't respond directly to POZ, but Merck spokesperson Janet Skidmore laughed at the suggestion, saying stoutly of Emini: "He's a scientist -- the data speak for him." Walker answered the question more soberly: "All [Emini] said to me [about the paper] was 'What do you think this means?' I'm being totally honest with you."

And it's hard not to believe this respected researcher with no bald vested interest in HIV vaccines. But in the vexing case of AC-06, it's equally hard to forget Garrett's recollection of yet another "prominent immunologist" seated near her during Walker's talk -- the one Garrett says "muttered under his breath halfway through...'We're fucked! We're so fucked!'"