Health systems across the southern hemisphere accounted a few months ago for their annual increase in flu cases, which along with Covid-19 could have overwhelmed hospitals. They never came.
Many countries in the southern hemisphere have instead experienced either record low flu or none at all, say public health specialists in Australia, New Zealand and South America, potentially saving tens of thousands of lives and offering a glimmer of hope as winter approaches the northern hemisphere. .
General practitioners in New Zealand have not detected a single case of influenza since they began screening patients in June, health data show; last year was approx. 57% of the samples, the total, positive.
The last flu cases discovered by major hospitals in Auckland, the country̵
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 on record. “Our excessive winter mortality rate has largely disappeared,” Baker said.
A tracking system that monitors a cohort of at least 30,000 people for flu-like symptoms shows as few as 0.3% of New Zealanders who reported coughing or fever a few weeks during their winter, which is a tenfold decrease over some previous years .
The trend applies across the Tasman Sea in Australia, where Covid-19 restrictions have also deeply submerged influenza and other respiratory diseases. The country registered more than 131,000 flu cases in the highest months of July and August last year, according to government data. In the same period this year there were 315.
“Cases have been falling off a cliff since March,” said Prof. Ian Barr, Deputy Director of the World Health Organization’s Center for Influenza Reference and Research in Melbourne.
Fewer than 40 Australians have died of the flu this year compared to more than 950 last year, “and there have been no deaths in the last three to four months,” Barr added.
Even in South America and South Africa, where lockdowns have been uneven or harder to enforce, and Covid-19 has spread widely and killed tens of thousands of people, flu rates have been well below historic rates or non-existent – despite increased testing for it. in America, according to the Pan American Health Organization.
This apparent contradiction – Sars-CoV-2 grows exponentially while influenza almost disappears – illustrates a key difference between the two viruses. The seasonal flu is not only less deadly, but significantly less virulent, Baker said.
The population has higher immunity to seasonal flu, whether acquired naturally or through vaccines, while travel bans imposed from March 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 some good news for the northern hemisphere countries that are heading into their own flu season, just as drier air and more time indoors are expected to increase Covid-19 prices. Even relatively less stringent quarantines appear to be surprisingly potent in suppressing influenza and other common respiratory diseases.
“You will still see a flu season, but I expect it would be much less intense,” Baker said. “The northern hemisphere, which is actively suppressing Covid-19 to some extent, should be given a lot of protection. [from influenza] by doing so. ”
That could mean more people are susceptible to flu strains in the coming years after not acquiring any immunity this year, Barr said, though he added the threat would be significantly reduced if people continued to wash their hands. thoroughly and wore masks in crowded areas even after the pandemic subsided.
In a year that will be studied by public health specialists for decades, it also points to new ways to combat the future flu pandemics that some researchers consider inevitable.
“[Before,] “it was thought that when a new flu pandemic virus arrives, all you can do is slow it down, you can not stop it,” he said. “We now know that if you had a pandemic influenza virus of sufficient severity, you could take the elimination method or even the exclusion method, as Taiwan has done with Covid-19.”