4:37 p.m., October 12, 2022, modified at 4:37 p.m., October 12, 2022
It is often the country to which scientists turn to anticipate the future flu season. Located in the southern hemisphere, Australia is traditionally affected by the flu epidemic before the northern hemisphere (France, Europe, United States, etc.). However, this year, the flu has been particularly strong in Australia. “What happened in Australia is an element of alert, but it is not the only one. For two years, the flu was kept at bay, thanks to the barrier measures against the Covid. This year, it will be difficult to maintain the same level of protection: masks, distancing, hand washing… Faced with this relaxation, there is a serious risk of an influenza epidemic”explained at the end of September the professor of immunology Alain Fischer at the Parisian. Here’s what we know about the Australian flu epidemic and the implications for France.
Australia’s worst flu season since 2019
In this country of 26 million people in the southern hemisphere, more than 220,000 cases of influenza were reported in 2022. Of these people, 1,784 were admitted to hospital and 305 died. By comparison, in 2021, when many Covid-19 restrictions were still in place, there was almost no flu season in Australia. Only 600 cases have been reported and there have been no deaths.
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In 2020, the first year of Covid-19, there were 21,000 cases and 37 deaths. In 2019, the flu season was also very bad as more than 900 people died from the flu and more than 300,000 cases were recorded. In 2018, 148 people died from the flu, 1,181 in 2017 and 273 in 2016. In France, on average, 2 to 6 million people are affected each year by the flu and around 10,000 people die, according to Public Health France
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In general, as Public Health France notes, “in 2022, influenza viruses actively circulated in temperate zones of the southern hemisphere, unlike the same time of year in 2021”.
“In Australia and South America (Argentina and Chile in particular), an influenza epidemic occurred earlier than usual, with a majority circulation of the A(H3N2) virus and a low to moderate impact. », note SPF. “In New Zealand, an early flu epidemic, of high intensity and with a greater impact in the elderly was observed. The viruses detected were overwhelmingly subtype A (H3N2),” also specifies SPF.
Lower immunity?
In Australia, as in France, the 2020 and 2021 flu season was more limited compared to previous years. Which may have weakened our immunity. “We haven’t had a major flu outbreak in two years and so our overall flu immunity has probably waned”confirmed on RMC
Professor Brigitte Autran, also president of Covars (Committee for monitoring and anticipating health risks.
A Covid wave and a simultaneous flu season?
Another problem, this winter, the two viruses (influenza and Covid-19) could circulate simultaneously. This was also the case in Australia where the flu season started in April during a wave of Covid-19. This possible concomitance is closely monitored at the General Directorate of Health, where it is explained that “Winter 2022 showed that co-circulation of influenza viruses and Covid-19 was possible, and high stakes again rest on the next campaign to protect the most vulnerable and to preserve the health system. The elderly, frail or immunocompromised will be exposed to this double viral circulation which can lead to a potentially severe influenza-Covid-19 co-infection. »
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What about vaccines?
In France, the vaccination campaign begins on October 18 for the most vulnerable audiences. The DGS explains that “average efficiency [du vaccin contre la grippe] generally varies between 30 and 60% depending on the circulating viruses (effectiveness is assessed each year at the end of the epidemic season). Vaccination therefore has a protective role during an epidemic. In fact, it reduces the risk of complications linked to the flu and makes it possible to avoid on average approximately 2,000 deaths per year among the elderly in the state of vaccination coverage”.
How effective was the vaccine in Australia where the flu season is almost over? According to the Australian health authorities, it can be described as“low to moderate”. So rather around 40% efficiency than 60%. In Australia, approximately 40% of the population is vaccinated against the flu. The rate is rather close to 20-25% in France.