Health officials estimate nine per cent of Nova Scotians have been vaccinated. (CBC)

Nova Scotia's chief public health officer says he understands people are confused, frustrated and angry about the way the province is distributing the swine flu vaccine.

"They may feel that every day that we are changing our decisions and they're not sure why we're changing," Dr. Robert Strang said at a news conference Tuesday.

Strang said the province was blindsided when told about the sudden shortfall of the H1N1 vaccine last Friday and had to decide how to maximize the vaccine supply that remained.

Nova Scotia abruptly shifted gears, limiting vaccinations to children between six and 59 months old, pregnant women, those in First Nations and health-care workers providing direct care to patients.

Strang said the province had about 80,000 doses of the vaccine left on Friday, which was simply not enough to inoculate all Nova Scotians under the age of 65 suffering from chronic health conditions — a group previously described as high-risk.

According to the Department of Health Promotion and Protection, 472,279 fall into that category — more than half the province's population.

In contrast, Nova Scotia has a combined total of 88,000 pregnant women, First Nations people, front-line health-care workers and children between six months and 59 months, and this number could reasonably be covered with the remaining vaccine, Strang said.

He said health officials have been losing sleep over the difficult decisions they've had to make.

"It's been a very tough time for our team, making these kinds of decisions," he said. "A lot of us aren't sleeping very well at night because this puts people at some risk.

"It does not sit well with us as health-care providers to have to say no to some folks, but that is the reality what we're dealing with and we're moving to be able to say yes as soon as possible.

More vaccine coming

Nova Scotia received 5,400 doses of the adjuvant-free vaccine for pregnant women on Tuesday and is expecting an additional 13,500 doses of the adjuvated version later this week.

Strang said some people with chronic conditions will be vaccinated when that happens, but the province will again limit distribution to those who need it most.

"In that group, there's many layers of people at different risk," he said.

People receiving chemotherapy, children with cystic fibrosis and those with severely suppressed immune systems will be among those who will be included in the expanded high-risk group, Strang said.

Health officials estimate more than 82,000 people, or about nine per cent of the population, have been vaccinated in Nova Scotia.

With files from The Canadian Press