Kindergarten classrooms emptied and cots full of tissues: for Northern Hemisphere families with children under 5, the last two months have been a succession of respiratory infections with an unseen frequency, duration and severity for years.
Why are we in this situation? Partly due to the aftermath of the measures that have been necessary to manage the pandemic; but there are at least two other reasons.
Complex situation. As explained in an article on New ScientistWhile it is common for respiratory viruses to take their toll in the winter months, the timing of their appearance and the number of hospitalizations they have resulted in this year are unusual. The flu started earlier than in recent years, immediately manifesting itself more aggressively, with very high fevers, respiratory and sometimes gastrointestinal symptoms.
According to Silvestro Scotti, general secretary of FIMMG, the Italian federation of general practitioners, never in the last 15 years have we had to deal with a peak comparable to that of this winter. And it doesn’t help that citizens now tend to associate the flu, for a psychological effect, with a less worrying infection than covid.
What viruses are we talking about. Children under 5 are particularly vulnerable to the consequences of the flu. But to complicate the situation there is a big comeback of the Respiratory Syncytial Virus (RSV), the main cause of bronchiolitis and pneumonia in children, whose circulation has increased in Europe in the last two months, putting pressure on health systems.
Great Britain, France, Ireland, Sweden and the Netherlands also report an increase in bacterial infections linked to Streptococcus A, a pathogen that usually causes a minor illness but which, if it manages to overwhelm the body’s defenses, can trigger serious and dangerous conditions for health.
Lockdown effect. In part these pathogens stand making up for lost time now that covid mitigation measures have eased and children have the opportunity to mingle again.
Since almost all childhood diseases are transmitted through mucus and saliva, it is clear that the lockdowns have had a profound impact on their spread. In 2020 and 2021 the circulation of these viruses was reduced to the limit and now they are making up for the backlog.
Harder variants. But there is another explanation on the table. In some cases, even the strains of viruses that are circulating are particularly aggressive.
This year the H3N2 flu strain is particularly widespread, among the most dangerous for children and the elderly. And the dominant Streptococcus A type is also responsible for more severe infections.
This human is mine! Another reason for the difficult season for the respiratory system is to be found in the so-called viral interference, i.e. in the relationships between the viruses that infect us, which interact with each other, determining not only when certain waves occur but also our susceptibility to infections.
When we are infected by a virus, this pathogen generally prevents other “competitors” from attacking us in order to have the exclusivity of our battered organism that it has now colonized. That’s why you see simultaneous viral waves appear all in the same period.
facili preys. Furthermore, infections weaken the human immune system leaving us more vulnerable to other viruses for the following weeks. The effects are very noticeable in the flu season: there is usually a first peak of cases of one form of flu, in the middle of winter, followed by a second peak of another form at the end of the season and at the beginning of spring. Influenza B usually arrives when influenza A is out of the game and takes advantage of the immune defenses reset by previous infections.
A new agent in the mix. In all of this we must not forget the covid factor. The SARS-CoV-2 coronavirus has entered this population of seasonal pathogens by reclaiming its spaces, anticipating the flu season thanks to the end of the anticovid restrictions and offering the other viruses a population with the defenses already tested by several pandemic waves.
Children who in many cases already have a covid experience behind them have arrived at this winter season further debilitated and with viruses ready to attack them again, thanks to the return to social life.