Wellington Dufferin Guelph Health Unit is preparing a pandemic protocol for the probable onslaught of "swine flu," more correctly "novel influenza A (H1N1) or novel A/HINI," but generally has to await guidance from federal and provincial public health officials.

In a phone interview Tuesday, Communications specialist Lucia Zdeb said the health unit has yet to receive such guidance. She couldn't say whether prioritization of who should receive the vaccine in the event of a short supply had been decided, and suggested contacting the higher authorities.

Medical Officer of Health Dr. Nicola Mercer was on vacation and not available for comment.

In an earlier e-mail response, Emergency Planning Co-ordinator Tracey Croft said, "I'm pleased to be able to tell you that we are currently very busy looking ahead and preparing for the fall at the agency — the written plan document is offline for a bit while we incorporate lessons learned from the spring H1N1 wave. We've also been active with our community partners and have been for some time on this issue."

At the Ontario Ministry of Health and Long-term Care, Andrew Morrison said consideration is being given to the need for priorities. He was aware of the U.S. models, but said the province is refining those. "There's a little more work still to be done," he said.

According to a source at the Public Health Agency of Canada, "the national policy decision on priority groups for pandemic vaccine will be made based on advice from a Special Advisory Committee made up of Chief Medical Officers of Health.

"This (tri-level committee) will make a recommendation to all provinces and territories to consistently apply the order decided on across Canada. Decisions about priority groups for the pandemic vaccine will be based on a number of factors including scientific evidence, legal, as well ethical and logistical considerations.

"As vaccine production continues over the summer, we are working to learn more about who is most affected by the virus and why. This will help to inform decisions around vaccine prioritization, which will be finalized close to the time when the vaccine is available," a PHAC representative said in an e-mailed response.

"We are still learning more about the H1N1 flu virus, as its origins remain uncertain. We know it involves elements of human, swine, and avian influenza virus, and the first case is believed to have originated in Mexico."

The Globe and Mail recently quoted Dr. David Butler-Jones, head epidemiologist at Public Health Agency Canada (PHAC), on what measures to take to slow down the spread in the meantime: "The key thing will be what we will all do at the end of day. These diseases spread because of what we do or don't do," he explains, listing the common advice to wash hands, sneeze or cough into one's sleeve and avoid others when symptoms appear.

Meantime, the advisory group to the U.S. Centre for Disease Control (CDC) says the most effective vaccine against the virus might be "initially available in extremely limited quantities," and has recommended priorities for two possible scenarios - based on which segments of the population are most at-risk.

Irrespective of the availability of vaccine, "pregnant women (and) people who live with or care for children younger than six months" are at the top of both lists.

If there is enough vaccine for 159 million people, health care and emergency services personnel would be next, followed by people between the ages of 6 months and 24 years, those between 25 and 65 with "chronic health disorders or compromised immune systems."

If vaccine is in shorter supply, the CDC model would restrict the health and emergency personnel to those "with direct patient contact." The next two priorities would differ substantially to include children 6 months to 4, rather than 24, years, and children between 5 and 18 years to those with chronic medical conditions.

CDC warns that the swine flu vaccine is not necessarily effective against the seasonal flu. "The novel H1N1 vaccine is not intended to replace the seasonal flu vaccine. It is intended to be used alongside seasonal flu vaccine to protect people. (Both vaccines) may be administered on the same day," CDC says in a July 29 news release.

The World Health Organization (WHO) has found the median age for the "pandemic" flu is "reported to be 12-17 years," based on data from five countries including Canada. But is also says that, "as the disease expands broadly into communities, the average age of the cases is appearing to increase slightly. This may reflect the situation in many countries where the earliest cases often occurred as school outbreaks but later cases were occurring in the community."

But WHO admits that those data may be flawed as "the full picture of the pandemic's epidemiology is not yet fully clear because in many countries, seasonal influenza viruses and pandemic (H1N1) 2009 viruses are both circulating and the pandemic remains relatively early in its development."

The organization says in a most recent release that risk factors are not definitively known, but it lists cardiovascular and respiratory disease, diabetes and cancer, As well as obesity is a possible factor. And "a few preliminary reports also suggest increased risk of severe disease may be elevated in some minority populations, but the potential contributions of cultural, economic and social risk factors are not clear. "