photography by Mckenzie James
A one-size-fits-all vaccine strategy developed to treat a flu epidemic isn’t the most effective, a York University study has found. Instead, vaccine strategies need to change depending on the specific characteristics of each infected region in Canada, and how easily the particular flu strain spreads.
“The window of time around the onset of an epidemic is going to be vastly different between a remote population and an urban one,” says York researcher and the study’s lead author Seyed Moghadas. “This is something public health officials need to pay attention to when developing vaccines. Different populations require different vaccination policies to minimize the impact of the illness.”
Research showed different age demographics of remote and urban populations have a significant impact on the outcome of vaccinations. Many remote areas of the country have a higher percentage of children, who are key transmitters of the flu virus, compared with urban centres, which generally have fewer children, but more young and middle-aged adults.
The study analyzed how the different areas responded when the flu vaccine was given – in either a single dose or two doses – before, during and after the start of the epidemic. The study revealed that for most vaccine strategies, the attack rates of the virus in the urban population were lowest for children under five; in the remote population, adults older than 50 had the lowest attack rates. However, those rates varied depending on when and how the vaccinations were given.
Early vaccination leads to the best outcomes, from both a public health and a socioeconomic perspective, he says. It reduces the rates of infection, hospitalization and death, along with resource stress on the health-care system.
This research is significant, especially in light of new technologies that promise quicker production of flu vaccines than the current egg-based technology, which takes four to six months.
“In the case of epidemic emergencies, that’s actually a very long process,” says Moghadas. “A timeline of six months for vaccine production means it is basically the end of the epidemic by the time we get the vaccine.”