TORONTO - As Canadians roll up their sleeves for the H1N1 vaccination, there will likely be a few faces in the long lineups cringing at the thought of what's to come -- perhaps not the vaccine itself, but the delivery method.

Needles have been known to elicit tears and even fainting episodes among those queasy, anxious or fearful about being pricked. And experts say festering thoughts of potential imminent pain from a shot could weigh on some people's decisions about whether to get vaccinated in the first place.

"I think people may have concerns about vaccines for a variety of reasons, but pain and the actual fear of getting the injection is often the barrier that prevents people from getting the vaccine," said pediatric psychologist Christine Chambers, a Canada Research Chair in pain and child health, based at Dalhousie University and the IWK Health Centre in Halifax.

"Certainly people who are anxious in general are more likely to be fearful about other consequences and other side-effects that they see might be associated with the vaccine."

Five to 10 per cent of people will admit to not getting vaccinated because of pain, said Anna Taddio, an adjunct scientist and pharmacist at Toronto's Hospital for Sick Children.

"It's going to be some way for someone to easily dismiss getting the vaccine because they're afraid of the needle," said Taddio, a professor of pharmacy at the University of Toronto. "So if we can treat the pain, if we can prevent pain, we can probably also increase people's willingness to get a vaccine."

Clinical psychologist John Walker with the University of Manitoba, said among the people he sees, the concern tends to be centred more on the needle than its contents.

"Some of these people will actually even faint if they need to give a blood sample to a family doctor or (if) they need to have an injection," he said. "Part of the treatment involves teaching them how to handle that.

For Walker, that involves having individuals understand both the problem and the thinking and emotion that goes with it, as well as learning how in gradual steps to face fears. One possible option is visualization and having someone imagine receiving an injection or watching someone else receiving one.

"You try to break a problem that seems quite overwhelming into smaller steps."

Chambers and Taddio say there are strategies that can help effectively reduce pain as well as anxiety, particularly among young people.

Chambers recommends parents purchase a topical anesthetic cream which can significantly reduce pain. Taddio suggests applying a numbing cream 30 minutes beforehand -- a cream which uses the same chemicals dentists use in patients' mouths.

For infants, breastfeeding during injections can help reduce pain. Distracting a child's attention away from pain could include talking to or giving small toys to babies and young kids, or bringing a small DVD player or iPod along.

Taddio said it's beneficial for children four and up to know about the needle beforehand because explaining what's going to happen will help to prepare them.

"Children might ... say, `Is this going to hurt?' And you'd say, `Well for some kids they say it's not comfortable. Other kids don't mind it at all. We don't know how it's going to be for you but we're going to have some things that we do to make it not bother you."'

Chambers said what doesn't work is parents reassuring or apologizing to children during medical procedures.

"What we encourage parents to do is to use distraction and to try to avoid saying things like, `It will be over soon,' `Don't worry,' `I'm sorry this is happening,"' she said. "Those types of things tend to make kids feel worse."