Those toying with the idea of self-infection with the current H1N1 swine flu strain now circling the globe doubt that there will be enough effective vaccine to stop the virus if it returns in the fall, especially if it swaps genetic material with the H5N1 strain or has picked up resistance to the antiviral drug Tamiflu. Even if drug makers switched to making a vaccine against a pandemic strain now, their total capacity is enough to make only one to two billion doses in a year, the World Health Organization said Wednesday. Triage decisions would have to be made about which of the world’s six billion people got the vaccine.

The online debates are often over details. Should you wait to self-infect till the season’s end, when the virus has evolved into the strain most likely to return in the fall? Should you get Tamiflu and take it at the first symptom? Should you check to see if local hospitals are empty, in case things go wrong and you need to be on a ventilator?

Michael Olesen, chief of infection control at Abbott Northwestern Hospital in Minneapolis and a flu pandemics expert, said he was not planning to seek out infection but was “taking a passive approach to getting infected.”

When he heard about the outbreak in Mexico, he said, he bought extra N95 face masks and had been planning to wear one on a flight to Detroit soon.

“Now I’m thinking of taking my chances” and forgoing the mask, he said. “That’s a change from a week ago. I think to myself, yeah, I’ll be miserable for a week  but that’ll beat maybe being seriously sick later.”

One of the first open debates of the idea of intentional self-infection was on Effect Measure, a public health blog with many posts by thoughtful people who say they are clinicians, epidemiologists, veterinarians and other professionals, sometimes in government, but who post under pseudonyms to speak freely.

On April 28, a user calling herself OmegaMom posted: “Just a quick note  I just got a Tweet from a mom suggesting ‘swine flu parties’ because the U.S. version seems to be a mild version. Can you speak to the utter insanity of doing this, please?”