Some flu experts are warning that with long lineups at flu vaccination clinics, those who need the vaccine the most are at risk of not getting it.

Across the country, vaccine clinics have been overwhelmed, with some patients being turned away because supplies have temporarily run out, and others reporting waits of more than two hours.

Many are complaining that those who need the vaccine the most -- pregnant women, children under five years of age and those with chronic illnesses -- are not being given first priority for the shots.

Health officials have said that anyone who want the vaccine can receive it, so clinics are not "triaging" patients to allow high-risk groups to get it first. Instead, officials are relying on the honour system, asking healthy, low-risk group to stay away from the clinics until those who need the vaccine the most can get it.

In an editorial in today's Globe and Mail, infectious disease experts Drs. Richard Schabas and Neil Rau say that while the federal government is boasting that there is enough vaccine for everyone, "this is a tad disingenuous."

"The vaccine is arriving in weekly aliquots of two million to three million doses. We don't actually have enough vaccine to immunize everyone right now," they write.

And, they note, timing is of the essence for those most at risk of serious complications of swine flu.

Local flu outbreaks typically peak within four or five weeks and then drop off rapidly. And in some areas of the country, outbreaks might already be beginning to peak.

"The worst of H1N1 will have passed from some areas of Canada -- Southern Ontario and the lower mainland of British Columbia, at least -- before healthy people can even roll up their sleeves," they write.

The fact that the vaccine takes about 10 days to fully protect from infection will extend the lag time even further, says Rau. In comments made to CTV's Canada AM Wednesday, he said the most vulnerable will probably be okay if they can get the vaccine within the next week. But two weeks from now may be too late for them.

"If we start to target the entire population with the vaccination campaign, we will not be able to get to everyone," he said.

The high demand for the vaccine has caught many health officials off-guard, and comes in spite of a recent Strategic Counsel poll that found that only half of Canadians wanted the vaccine. That survey, for CTV and The Globe and Mail, suggested 51 per cent of Canadians did not plan on getting immunized.

But the sudden death this week of an otherwise healthy boy in southern Ontario, along with other deaths in Ontario and Saskatchewan has made many parents worried, with some telling CTV News that their ambivalence to the vaccine was erased when they heard about those deaths.

The deaths have also been followed by a sudden a stampede to children's hospitals, some are reporting.

The emergency room at Toronto's Hospital for Sick Children has seen a big surge in patients -- 400 in the last 24 hours alone -- which officials say is a record. And the Children's Hospital of Eastern Ontario says it saw a 49 per cent jump in emergency room visits over the last week, with a 100 per cent rise in visits Monday alone.

Rau noted that while the recent deaths are tragic, they weren't unexpected and are not a reflection of a sudden increase in virulence of H1N1.

"It would seem that this flu is attacking young healthy people. But the truth is this is the medical equivalent of being struck by lightning. This is still an incredibly rare event," Rau insisted.

He says the death should remind people in high-priority groups to get the vaccine as quickly as they can, but it shouldn't worry otherwise healthy people that the virus is going to kill them as well.

As for the sudden interest in the vaccine, he encourages those who are most at risk to get the vaccine but he also reminds that all of the southern hemisphere braved swine flu this past summer, with low rates of death.

"Australia faced their entire outbreak, full-blast, without a vaccine in hand," he noted.