There are several types of influenza viruses that change from year to year, some of which most affect the elderly, while others target young people and adults.
In a report published by the Spanish magazine "Quidaty Plus", writer Covadonga Diaz says that interest in influenza viruses decreased a lot last winter due to the spread of the "Covid-19" epidemic, but it returned again to the fore this winter.
According to the author, there are 4 main types of influenza viruses, including two, "Influenza A" and "Influenza B", which are transmitted between humans, and may cause the spread of epidemics.
"The behavior of these viruses is similar in some respects, but there are fundamental differences between them, some types of viruses affect the elderly more, while others target young people and adults," said Professor Ismail Huerta, head of the Epidemiological Surveillance Department of the Ministry of Health in the province of Asturias.
As for influenza A viruses, we will talk about two subtypes: H1N1 and H3N2.
Why swine flu affects adults and young people more than the elderly?
H1N1 swine flu is one of the influenza A viruses that affects young people and adults more than the elderly, due to the fact that this virus has a similar structure to the one that caused the 1918 pandemic.
In fact, many elderly people born in the twenties of the last century contracted the Spanish flu, which gave them a kind of immunity to this virus.
Professor Huerta explains that this immunity is not complete, but it has contributed to protecting the elderly from this virus, except for those who suffer from cancer or other chronic diseases that affect their immunity.
The H3N2 virus affects the elderly more severely
The “H3N2” virus belongs to the family of influenza A viruses, and it appeared in the 1960s, and affects the elderly more than others, and is often associated with outbreaks of serious epidemics characterized by high incidences of hospital admissions, stays in intensive care units, and mortality rates.
What are the characteristics of influenza B viruses?
For influenza B viruses, it is not related to sub-viruses, but rather strains, specifically the Victoria lineage and Yamagata lineage, which are viruses that can cause epidemic waves.
The Victoria strain is a type of virus that has mutated a lot over the years, which is why it keeps spreading because people who have it can infect them again.
In contrast, Yamagata viruses change slightly and do not spread widely.
What virus is expected to spread this winter?
Huerta stresses that it is difficult to predict the influenza virus that can spread in the coming period, and adds, “A relative spread of the H3N2 virus occurred in southwestern Europe, but we still do not know if it will spread in Spain, the influenza season will depend a lot on people’s behavior and the nature of The restrictions imposed on them, certainly the situation will be similar across Europe because it is a global virus, if there is less movement between countries it is difficult to see large epidemic waves.”
The "H3N2" virus had spread in Spain during the winter of 2016/2017, and a large number of serious cases and deaths were recorded, and in the following winter the Victoria subtype spread.