"However, that may also mean a delayed or diminished second wave, rather than no second wave in those geographic areas, because the infection may travel through the same geographic area by going through different social networks," he added. "Susceptibility in different social networks may change with weather changes."
"With influenza, one must prepare for the worst and hope for the best," said Dr. Pascal Imperato, dean and distinguished service professor of infectious disease at SUNY Downstate Medical Center in New York. "That said, there is a real risk that many will opt not to be immunized if they perceive that an epidemic is unlikely. Such decisions will be reinforced by widespread belief that the vaccine carries risks."
"It's an interesting hypothesis but difficult to prove," said Dr. Howard Markel, infectious disease expert and medical historian at the University of Michigan at Ann Arbor. "Don't forget that perhaps 5 percent of New Yorkers, at most, contracted H1N1 last spring. That means that at least 95 per cent of those living there are still susceptible.
"The bottom line is that most of us still need vaccine. The tragedy of such media speculation would be for Americans to be under a false impression that they were immune when they are not."
And the consequences, some say, are too heavy to risk.
"The type of speculation that public health authorities are engaged in that raises the possibility that areas such as New York City may have experienced so much flu during the first wave in the spring and summer that they will have very mild second waves or no second waves all is very appropriate after flu season is over, or in private discussions in conference hallways," said Bill Muraskin, professor of urban studies at Queens College in New York. "But to raise them in a way that could easily become public now seems ill advised. ... These types of speculations are not helpful."
The ABC News Medical Unit contributed to this report.