- Statistical data show that the number of people suffering from flu in the 2020-2021 season has clearly decreased compared to the average from previous years. The situation changed only this year in the fall, when the number of cases increased significantly
- According to specialists, the decline in the incidence in previous seasons was influenced by restrictions introduced by subsequent countries, travel restrictions, hygiene rules, and finally complete lockdowns
- The discovery of Australian scientists may contribute to a change in thinking about next generations of vaccines
- You can find more such stories on the Onet homepage
Australian scientists in the magazine “Nature Reviews Microbiology” informed about the discovery. Some time ago, they decided to investigate a certain dependence that specialists noted. In the first year of the pandemic, spring 2020 saw the largest drop in influenza incidence in modern history. First in the southern hemisphere (the flu season here usually lasts from June to August), and later in the northern hemisphere the number of cases was record low.
It was similar in Poland. The charts of the National Institute of Public Health – National Institute of Hygiene show that the number of people suffering from influenza in the 2020-2021 season has clearly decreased compared to the average for previous years. The situation changed only this year in the fall, when the number of cases increased significantly.
According to specialists, the coronavirus certainly contributed to the decline in the incidence in previous seasons. Restrictions, travel restrictions, hygiene rules, and finally complete lockdowns introduced by successive countries prevented the free spread of the flu virus. Moreover, school closings may have contributed most to this, as it is the children who get infected most quickly and bring the virus home.
Influenza viruses are divided into four types – A, B, C and D. For people, only the first two are a problem, because they are responsible for infections in the fall and winter season. Meanwhile, the type C virus causes virtually only mild infections, and the D virus only affects cattle.
Type B in this case is more stable than type A and is divided into two genetic lines: Victoria and Yamagata. Interestingly, from April 2020 to August 2021, infection with the Yamagata lineage has not been registered anywhere in the world.
Thus, experts not only noted the record low number of infections, but also reduced the genetic diversity of influenza viruses.
The rest of the text below the video.
As the researchers note, this line of influenza virus was already weaker than the other subtypes. Yamagata’s germs were less contagious, and they could not “hide” in the bodies of other animals like type A viruses. However, it must be borne in mind that the absence of Yamagata-induced disease in the world databases does not necessarily mean that this variant of the flu completely extinct. The databases are not systematically maintained, and therefore some cases of the disease could simply be omitted.
Flu and the vaccine
The discovery of Australian scientists may contribute to a change in thinking about next generations of vaccines. If Yamagata is indeed extinct, two scenarios are possible. The first of them may mean a return to the so-called a trivalent vaccine, i.e. one that protects against two types of virus A and strain B / Victoria. Such a solution could contribute to an increase in the production and availability of flu vaccines.
The second possibility is that the pathogens of another variant of the influenza A virus will be added to subsequent vaccines, which would increase its effectiveness.
Source: “Nature Reviews Microbiology”
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