Health systems in the southern hemisphere were preparing a few months ago for the annual increase in flu cases, which alongside Covid-19 could have overflowed hospitals. They never came.
Many countries in the southern half of the world have experienced low levels of flu or low records, according to public health experts in Australia, New Zealand and South America, which have potentially saved tens of thousands of lives and offer some hope as winter approaches the northern hemisphere.
New Zealand GPs have not detected any flu cases since they began screening patients in June, according to health data; last year, approximately 57% of the samples they collected were positive.
The last flu cases detected by major hospitals in Auckland, the country’s largest city, were in April. “It̵7;s fantastic. There’s nothing. No flu,” said Michael Baker, a professor of public health at the University of Otago in Wellington.
New Zealand’s Covid-19 rates are among the lowest in the world, but even despite the pandemic, people in the country have experienced their healthiest cold months. “Our maximum excess of winter mortality has largely disappeared,” Baker said.
A monitoring system that monitors a cohort of at least 30,000 people to detect flu-like symptoms shows that only 0.3% of New Zealanders reported coughing or fever a few weeks during their winter, a split over some years previous.
The trend continues throughout the Tasman Sea, Australia, where Covid-19 restrictions have also profoundly affected rates of influenza and other respiratory diseases. According to government data, the country recorded more than 131,000 cases of influenza during the peak months of July and August last year. During the same period this year, there were 315.
“Cases have fallen off a cliff since March,” said Professor Ian Barr, deputy director of the World Health Organization’s leading influenza reference and research center in Melbourne.
Less than 40 Australians have died from the flu this year, compared to more than 950 last year, “and there have been no deaths in the last three or four months,” Barr added.
Even in South America and South Africa, where blockades have been erratic or more difficult to enforce, and Covid-19 has spread widely and killed tens of thousands of people, flu rates have been well below historical or non-existent rates, despite increasing testing in the Americas, according to the Pan American Health Organization.
This apparent contradiction (Sars-CoV-2 grows exponentially as the flu virtually disappears) illustrates a key difference between the two viruses. Seasonal flu is not only less deadly, but significantly less virulent, Baker said.
Populations have greater immunity to seasonal flu, either acquired naturally or through vaccines, while travel bans instituted from March onwards disrupted the normal migration of the virus from the northern hemisphere to the south.
As an unprecedented live experiment on a massive population, it could offer good news for northern hemisphere countries toward their own flu season, just as air is expected to be drier and longer. inside increase rates of Covid-19. Even relatively less strict quarantines appear to be surprisingly potent in suppressing influenza and other common respiratory diseases.
“You’d still see a flu season, but I hope it’s a lot less intense,” Baker said. “Northern Hemisphere countries that are actively abolishing Covid-19 to some extent should have a lot of protection [from influenza] doing that “.
It could mean more people are susceptible to flu strains in the coming years as they have not acquired any immunity this year, Barr said, although he added that the threat would decrease significantly if people continued to wash. hands thoroughly and wearing masks in crowded areas. even after the pandemic subsided.
In a year that public health specialists will study for decades, it also points to new ways to combat future flu pandemics that some scientists consider inevitable.
“[Before,] it was thought that when a new pandemic flu virus arrives, all you can do is cushion it, you can’t stop it, ”he said.“ Now we know that if you have a pandemic flu virus of sufficient severity, you could adopt the elimination approach, or even exclusion, as Taiwan has done with Covid-19 ”.