LETHBRIDGE – More people in the southern health zone are immunized against this year's flu strains, and this may be part of what this year represents relatively low infection, hospitalization and mortality.
In the southern health zone, nearly 95,000 people were vaccinated in this flu season, compared with less than 92,000 in 2017/18 and approximately 88,000 in 2015/16.
Doctor Vivian Suttorp says that the predominant influenza strain is the A-H1N1 influenza virus, very similar to that which caused 428 deaths across Canada and more than 33,000 hospitalizations in 2009/10.
According to the most recent figures on the AHS website, only one influenza-related death, 54 hospitalizations, 302 cases of laboratory confirmed influenza A and 2 influenza B were reported in the southern zone.
Calgary has so far recorded 9 deaths, Edmonton 7, Central Health Zone 9 and North Zone 2.
Nearly 2000 hospitalizations and almost 500 hospitalizations in Calgary, 629 infections and 145 central hospital admissions, nearly 1,000 infections and 300 hospitalizations in Edmonton and more than 1,100 infections and more than 170 hospitalizations in the northern zone were reported.
Suttorp says one of the most interesting things this year is that there has been no epidemic in the facilities for further care.
"So, any facility for seniors or our hospitals that speaks about immunization of seniors is the fact that this influenza A has an effect on seniors, but not as strongly as younger individuals.
"Where we see a lot of numbers in previous years, that's when we have some epidemics. So if we have an outbreak in the elderly, it's common – even if you've put in many infection controls – it could be many people who got it because they are together in a communal environment. The fact that we did not have any outbreaks and we have very good immunization in our seniors and the vaccine is very effective, we did not see the outbreak. "
He adds that 80 percent of the people who were hospitalized throughout the province have been vaccinated. Most of them were also at the age of 65 and many of them were also children who did not have immunity to the H1N1 virus.
"We see a more serious disease in young people where our immunization is the lowest," explains Suttorp.
This year's vaccine is more than 70 percent effective. Compared to 2017/18 and 2013, when the vaccines were not so good.
So why is this year's vaccine much more effective than in recent years?
"Every year, the World Health Organization (WHO) is showing when we look at all surveillance data that should include the Northern Hemisphere vaccine and the Southern Hemisphere vaccine. When it comes to the A-H3N2 influenza that prevails over the year, a certain the virus is changing faster, and so for 6 months flu season this virus already has some changes, so the vaccine is less effective compared to H1N1.
This means that for those who have received H1N1 flu in 2009, they may have some immunity from this year's H1N1 because they are similar.
However, Suttorp warns that boosters are needed because there are other strains that are also contained in this year's vaccine, including influenza B, which may also happen more often.
"When we have the tip of influenza A, as we did at the beginning of January, it is not unusual that we have a second wave of another influenza strain in one of the strains of type B. We look forward to our guards."