Epidemiologists in Bulgaria Predict a Severe Flu Season

1. What flu strains will attack us this year?

It is assumed that in the 2021/2022 season, influenza viruses will be circulating, which are similar to the viruses included in the influenza vaccines recommended by the WHO for the countries of the Northern Hemisphere, namely:

∙ A / Victoria / 2570/2019 (H1N1) pdm09;

∙ A / Cambodia / e0826360 / 2020 (H3N2);

∙ B / Washington / 02/2019 (B / Victoria lineage);

∙ B / Phuket / 3073/2013 (B / Yamagata lineage).

It is not yet possible to predict which of these viruses will dominate.


2. To what extent does the flu vaccine protect us?

The effectiveness of influenza vaccines is not 100%, but they provide protection against severe forms of influenza and complications, especially in high-risk individuals. According to scientific publications, with influenza vaccines:

∙ The outpatient examinations due to influenza in the general population are reduced by 50-60%.

∙ Influenza hospitalizations for people over 50 is decreased by 57%.

∙ There is a reduction of the number of children admitted to intensive care units by 74%.

∙ Reduction is observed by 52% and 79% hospitalizations in people with chronic lung disease and diabetes, respectively.

The effectiveness of influenza vaccines depends on the age and immune status of the vaccinated person, but mostly on the antigenic proximity between vaccine and epidemic influenza viruses. Vaccines have the highest efficacy against influenza B viruses, as they are the most genetically stable, and the lowest against influenza A (H3N2) viruses, which are the most variable. So it is important for the effectiveness of vaccines which influenza virus predominates during a...

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