Flu season 2022-2023: what can we expect?

To determine whether or not the flu season in Belgium will be severe, the influenza activity in the southern hemisphere usually provides an indication. And it doesn’t look reassuring.

While summer is coming to an end in Belgium, winter is just over in Australia with an alarming peak of covid-19 and flu cases. In fact, the country has had its worst flu season in five years.

The past six flu years in Australia

At the same time, the number of Covid-19 cases has exploded. A dangerous and double viral shock, dubbed a “twindemic” by health experts.

What does this mean for the flu season in Belgium?

These trends lead to fears that Belgium will also have to deal with a double epidemic this winter, with a new wave of Covid-19 coinciding with an upcoming flu season. Because there have been few infections in recent flu seasons, our immune system has only very limited exposure to flu. ‘It is impossible to predict exactly when the next flu season will start, which virus strain will dominate and how serious the epidemic will be,’ says Marc Van Ranst, professor of virology and epidemiology at KU Leuven. “The data on influenza activity in the southern hemisphere is not very reassuring, as for the first time since the start of the pandemic, not only was the flu back with a vengeance, but the flu season in Australia was particularly virulent. In addition, the number of Covid-19 cases rose, making a ‘twin epidemic’ of influenza and the coronavirus, and a possible double infection, a potential risk.’

How dangerous is such a double infection with flu and corona?

The risk of co-infection with corona and flu is real. This is apparent from a study in Wuhan in 2020 in which 12 percent of a selected number of covid patients were also infected with the flu. You can get co-infected with influenza and another virus, bacteria, fungus or yeast because the mucous membranes are affected and therefore more sensitive. But it’s not clear whether such a double infection increases the risk of death or hospitalization. However, infections with corona and flu may not so much occur simultaneously, but rather sequentially, with a patient first experiencing one infection and a few weeks later the other. We don’t know what the effect is. It is possible that the immune system is so sharpened by the first infection that the second virus no longer has a chance. That’s because infection with one respiratory virus triggers infected cells to release interferons that block the process of multiplication of all respiratory viruses, forcing other pathogens to lose out.

How dangerous is the flu?

In most cases, the flu is a benign condition, but especially in the elderly, pregnant women and the sick, flu can cause dangerous complications. dr. Aurore Girard, vice president of the general practitioners’ association Société Scientifique de Médecine Générale (SSMG): ‘Flu causes more damage than people think. It can lead to serious complications, increasing the risk of heart attack and pneumonia, even if the person is in good health. Influenza places a heavy burden on healthcare during the winter season. After two years of pandemic and health measures, the immunity of the population has weakened, especially of the over-65s. And given the risk of a double infection, an annual flu vaccination is the best way to protect people from both the disease and possible complications. Although the covid vaccine still seems to take precedence, it is crucial to also have a clear prevention policy against flu to ensure that people aged 65 and older are well protected every year.’

What should we do to fight the flu?

The Superior Health Council recommends vaccinating people who are at risk or threaten to get the flu from mid-October, because the vaccine offers optimal protection after 10 to 15 days. In Belgium, an average of 59 percent of people aged 65 and older are vaccinated against flu, while a vaccination coverage of 75 percent is required for optimal protection. In addition, the golden rules are washing hands, wearing a mouth mask, not going to work when you are sick and keeping your distance. So the corona measures. During the winter of 2020-2021, they contributed significantly to contain the flu. The B/Yamagata, one of the four flu strains in circulation, has even been eliminated. ‘As a result, we know what we have to do to limit influenza, but nobody wants these measures anymore because of the high social cost,’ says Van Ranst.

So a vaccine. But is there no vaccine fatigue?

During the winter of 2020, there was a great willingness to be vaccinated against flu. “Everyone was afraid of the coronavirus, but also of the influenza virus,” says Van Ranst. ‘But the following year we saw the figures stabilize and even decrease’, it sounds. According to Van Ranst, vaccine fatigue plays a factor in this. It remains to be seen whether there will be a large willingness to prick this year.

Also read:

Flu vaccine or not? 10 misunderstandings

Flu vaccine not useful in children with chronic diseases

– The flu season usually runs from November to March.

– On average, 500,000 people in Belgium are affected by a flu syndrome each year, ie about 2 to 8 percent of the population.

– A moderate flu epidemic affects about 5 percent of the population (550,000 out of 11 million inhabitants).

– A stronger flu epidemic affects about 10 percent of the population (1,100,000 in 11 million inhabitants).

– On average, 1 in 1,000 flu patients develop complications that require hospitalization.

– More than 90 percent of deaths concern people aged 65 or older.

The article is in Dutch

Tags: Flu season expect

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