TORONTO — Families in several provinces were expressing outrage and concern Tuesday after they said their children got double the recommended dose of the H1N1 vaccine, but at least one medical expert said there's little need for concern.

Parents in Ontario, Manitoba and British Columbia have reported that their children received the amount in the adult dose instead of the pediatric dose of the swine flu shot.

The Public Health Agency of Canada has received reports of the wrong dose being given out to children but cannot provide exact figures, said spokeswoman Nadia Mostafa, who referred the question to provincial health ministries.

The agency's guidelines call for adults to receive 0.5 ml in a single shot of the adjuvanted vaccine. The recommendation for children between six months of age to nine years is two half doses at least three weeks apart.

A stressed-out father in Delta, B.C., urged parents to check the dose themselves before their children get the shot. Jeevan Tauro said his three-year-old daughter and 17-month-old son were given the 0.5 ml dose at a Burnaby walk-in clinic Nov. 3.

In a telephone interview from his home Tuesday, Tauro said he asked the doctor if they should return to the clinic three weeks later to get the second half of the flu shot, but the doctor told him not to.

The doctor said there was only one shot and no subsequent vaccination, "so that raised my doubts (as to) what he had actually done," said Tauro.

The receptionist told him his children had received the full adult dose, he said.

Tauro said his son Ruhin developed a fever the next day, and suffered a seizure four days later and was rushed to hospital. He said a pediatrician told him two days later that Ruhin's high fever was related to the flu shot and that the fever had caused the seizure.

He was told to give his son Tylenol and the boy is doing better now, he said.

Fraser Health Authority spokeswoman Joan Marshall said "our medical health officer has followed up with the family and is also following up with the doctor."

Information about the H1N1 vaccine has been provided to all Fraser Health physicians through regular medical health officer updates, Marshall said.

The Public Health Agency of Canada says on its website that reactions to the vaccine were higher in clinical trials for children who received a full dose as compared to those who received two half-doses.

The agency says the majority of adverse events are minor reactions, such as soreness at the injection site or a slight fever. However, it does state that sometimes more serious events are reported -- including seizures in rare cases.

It says the average reported rate of serious adverse events is about one case for every 100,000 doses distributed.

Dr. David Scheifele, director of the UBC Vaccine Evaluation Centre at B.C.'s Children's Hospital, said dosing errors happen all the time with seasonal flu vaccine and parents shouldn't worry.

"Giving a young kid the adult dose may increase the mild side-effect rate slightly. The leg will be a bit sorer, the kid a little crankier. And maybe the risk for fever is increased," he said.

"But the rate of high fever sufficient to trigger febrile convulsions has been extremely low with this vaccine."

If someone has the flu or is exposed within a couple of days of getting the vaccine, the flu shot won't prevent them from getting sick, he added.

In Ontario, Peel Public Health said 11 children in Brampton received the full swine flu dose on Nov 2.

Claudine Kneer said her two boys, ages eight and six, received the full dose at a public clinic in Espanola in northern Ontario, just west of Sudbury.

Kneer said her six-year-old got his flu shot first.

"There was a lot of confusion and chaos in the moments after we mentioned that we think he had gotten the wrong amount," she said in an email interview.

"A different nurse, going on what the misinformed nurse thought should be administered, then hastily gave my older son a second dose of vaccine.

"In the end, they both got a full dose."

Kneer said her family is outraged at the mistake and "praying our boys are going to be OK."

Last month, a Winnipeg woman said her five-year-old son had received a higher dose.

Chief medical officers of health in Saskatchewan and Nova Scotia said they had not heard about dosing problems in their provinces.