In 2023, there were many children in bed with high fever and swollen tonsils due to infections Streptococcus. With the lack of Covid protections, such as masks and distancing, the infection has started to restart, with the 13-16% of the samples examined testing positive for streptococcus. These are the data that emerged from a work published on Lancet Microbe, conducted by researchers from the Paediatrics and Microbiology of the Fondazione Policlinico Gemelli IRCCS and the Catholic University. What are the causes of this increase? How to best manage the infection?
I STUDY
The research, conducted over a six-year period (2018-2023), investigated the incidence of infection with Streptococcus pyogenes (GAS), analyzed by the privileged observatory of the pediatric emergency room of the Gemelli Polyclinic, directed by Professor Antonio Chiaretti, associate of general and specialist pediatrics at the Catholic University, who, in this period of time, has collected over 1,800 samples.
«In the years of the Covid pandemic, that is from 2020 to 2022 – explains the Professor Maurizio Sanguinetti, professor of Microbiology at the Catholic University, director of the Department of Laboratory and Infectious Sciences, director of the Microbiology UOC, Policlinico Universitario A. Gemelli IRCCS, – we have observed a significant reduction in Streptococcus infections, both in terms of the quantity of samples received (for reduced access to our hospital clinic), but also a significant reduction in the percentage of positive samples. The non-pharmacological protective measureslike the mask, have in recent years reduced contact with the microorganism and infection. However, when these protections were removed in 2023, we observed a restart of the infection, with an incidence quickly returning to the levels of the pre-pandemic period, when positive samples were 13-16% of all those examined”.
THE YOUNGER CHILDREN ARE AFFECTED
The real difference recorded in 2023, compared to the previous year, lies in the age group of those affected. Usually, those infected were children of school age and pre-adolescence, while last year the age dropped, mainly affecting children. pre-school children (3-6 years).
«The suspicion is that the children – explains Professor Sanguinetti – having been protected in an important way by staying at home and wearing masks, have not developed the normal, partially protective immunity against the infection. This is a very important concept that concerns the benefits of coming into contact with microorganisms; during the pandemic, due to causes of force majeure, there was on the contrary a massive use of these tools which generally reduced contact with all microorganisms”.
THE IMMUNOLOGICAL DEBT
«But contact with microorganisms – continues Professor Sanguinetti – is essential for ‘training’ our immune system to respond to infections. The hypothesis is therefore that the reduced contact with this microorganism has resulted in a so-called ‘immunological debt’ which prevented them from developing even partial protection against the microorganism and this led to a greater incidence of infections. Therefore, if on the one hand protection from infections is fundamental, especially in a moment of emergency such as that of the Covid-19 pandemic, it is equally clear that contact with microorganisms also acts as ‘prevention’ because, a low level contact determines the development of a certain protection, the establishment of a certain immunity which is then reactivated more effectively when it comes into contact with the microorganism.”
WATCH THE DIAGNOSIS
A positive sample, in the case of Streptococcus, always indicates a symptomatic infection and not colonization, because it is a very important human pathogen.
«With respect to the epidemiological evolution, our research and various other evidence published in the literature point to many small outbreaks of Streptococcus pyogenes almost everywhere, with an increase in invasive pathologies, linked in particular to the M1 immunotype which is the most serious and virulent. This leads us to another important reflection – continues the expert – and that is that the diagnosis of these infections must be carried out appropriately. THE rapid antigen tests carried out in the pharmacy can be a valid screening tool, even if they are burdened by many false positive and false negative results. But if a child is highly symptomatic (high fever, enlarged and inflamed tonsils) and tests negative in the rapid test, it would be appropriate repeat the test in a laboratory to confirm this diagnosis. The same reasoning also applies in the event of a positive rapid test; only a throat-tonsillar swab carried out in the laboratory, followed by cultural examination (and from a possible in vitro drug sensitivity test, i.e. an antibiogram) allows the microorganism to be characterized, with both diagnostic and epidemiological implications for evaluating the possible circulation of hyper-virulent strains. Therefore, yes to the test in the pharmacy, but in some cases it must be integrated with a confirmation/in-depth analysis in the laboratory”.
NO ALARM
«No alarmism therefore – concludes Professor Sanguinetti – because this is a disease that we know well, but at the same time we must avoid being superficial because in 2023 there was an important resurgence and because this microorganism can cause invasive infections, even in healthy individuals and important sequelae years later, at the level of the kidneys (post-streptococcal glomerulonephritis), heart valves and joints, in particularly in the case of the M1 strain”.
