Editor’s comment:
I interviewed Dr. Mazzoli via skype, a very interesting piece resulted, but above all because it highlights how scientific authorities, such as Zeichner and Cruz, highlight that it is early and difficult to demonstrate the true role of COVID-19 on children, but above all that children can play a very important role in viral transmission since many of them are asymptomatic or with mild symptoms, while carrying the virus. Zeichner said that for this reason “it is essential to practice all social distances, hygiene and all precautions recommended by health authorities to minimize transmission from children to others, including family members at greatest risk of infection, such as grandparents or members of the family with chronic medical conditions “. Zeichner is working on an innovative COVID-19 vaccine in his laboratory.    A S


Sandra Mazzoli’s article

There are now more than 500,000 cases worldwide of COVID-19, (ECDC Situation update worldwide, March 27, 2020), the disease caused by this new Coronavirus, SARS-COV-2. Since 31 December 2019, 528,000 cases of COVID-19 have been reported worldwide, in accordance with the definition of Case and test strategies in the affected countries, including 23,669 deaths. A total and global health emergency. This aggressive virus in a short time caused the WHO to proclaim the state of Pandemic on February 11, 2020, when the first cluster of infections reported in China occurred at the end of December 2019.

A mutation, or perhaps more, has allowed the virus to overcome the barriers between species up to adapt by the bats, which would represent the evolutionary reservoir, to man, or through an animal, perhaps identified, intermediate, the pangolin and/or others, or directly by implanting on a human individual who would have turned into a very active asymptomatic diffuser (superspreader).

It is still not known to know for sure. Mutations also allow the virus to have an increased affinity for the receptor to which it must bind in order to penetrate the human cell to be infected.

Was this the decisive variation, the one that made the difference for greater aggression? This virus then passes directly from man to man, causing direct interhuman transmission (Chan JFW et al., 2020). With a very high transmission rate, 83%, in the intra-family context. Precisely in this context and in others in society, one wonders what role children can play, since, in asymptomatic children in China, there are reported cases of the presence of opacities characteristic of lung infection and positivity for SARS- COV-2 RNA. However, data  are also confirmed by other studies

(Bay Y. et al., 2020). Children appear to be less likely to become infected or have a more severe COVID-2 disease. But this is completely true and what are the possible causes? or the data that are currently available and the relative scientific studies, very few, do not allow us to assert it with certainty? Initially, the available data on 138 children still appeared to be few despite being published in the prestigious JAMA journal (Wang D. et al., 2020).

Just these days, a work by Dong Y. and collaborators on 2143 children, mean age 7 years old, of the Chinese epidemic, with suspected or confirmed COVID-19, is being printed on Pediatrics. 13% of children with confirmed virology were asymptomatic. 50.9% were paucisymptomatic, 38.8% had moderate disease and only 0.6% of the symptomatic ones progressed to ARDS (Acute Respiratory Distress Syndrome) or multiorgan System Dysfunction, a lower percentage also of adults. The only one died. However, children are at all ages at risk and, when in preschool age and very young (infants), they were more likely to present severe clinical manifestations from SARS-COV-2. However, 32.7% of babies had positive X-rays in both lungs.

The transmission between person to person, very often intra familiar, seems the main one. Infants seem particularly vulnerable to this infection. Younger age, concomitant lung disease, and immuno-compromised states have already been risk factors in infections mediated by other non-COVID-19 Coronaviruses, both in China and Norway (Li YT et al., Heimdal I et al.). However, studies have shown that viral co-infections are present in two-thirds of cases. At the moment, according to the Editors Cruz A. and Zeichner S. of the Pediatrics magazine, the risk attributable to the virus in the determinism of a severe disease COVID-19 is still under discussion. In fact, in Dong and colleagues’ work, tests for other viruses were not standardized and two-thirds of cases were clinically diagnosed without virological confirmation. The more severe symptoms in the population without virological confirmation may have been linked to the presence of other untested pathogens.

Also in a “letter” to Nature Medicine published on March 19, 2020, on the severity of COVID-19 researchers (Wu JT et al., 2020) reported data that children in Wuhan were less likely to be infected with the virus and die, 40% less, than adults aged 30 to 59 were.

The risk of presenting a symptomatic infection appears to increase with age.

The reasons why children seem less prone to severe infections are currently not scientifically investigated and/or confirmed. Hypotheses can be made: biologically one can suspect that cellular receptors for the virus may not be present or that they are modified. The immunity present in children against other viruses, including many Coronaviruses, agents of colds, could cover the infection due to the presence of cross-reacting antibodies, immaturity or the different reactivity of the infant immune system could not induce the serious heavy immune cytokine cascade, responsible for lung engulfment. Very important, in fact, is this immune cytokine reaction, which is triggered in some infected subjects, and which represents one of the main causes of death in adults. Is this the reason why children would seem less affected? the stimulations that we undergo throughout our life by the various microorganisms determine our overall immune response and vary. All this is crucial against the viral attack. Also in COVID-19, we see that the death toll in our population seems higher than that found in other populations in Asia. Are we perhaps more receptive or susceptible, or are other Coronaviruses (SARS, MERS) circulating much more from them that determine in those populations cross-reactive antibodies that have decreased their lethality? Even our children of school age are very exposed to Coronaviruses of colds and therefore more immunologically resistant. Receptors and immunities can represent the “keywords”. Only at the end of this pandemic, we can probably draw conclusive data and, above all, with the study of the antibody response to the virus.

We still know very little about this virus: we must, however, consider that our children can play a really key role in the asymptomatic transmission of the virus itself; data show that in addition to carrying the virus mainly at the nasopharyngeal level (Dong Y. et al., 2020), they can eliminate it with feces (Jieao C et al., 2020) for several weeks after diagnosis, with the possibility of oro-fecal transmission and with the possibility of spreading the virus at home, at school, and in the community. Understanding whether SARS-COV-2 has the possibility of being detectable for a long time, as for other Coronaviruses in the respiratory secretions of healthy babies, will be important. According to Cruz and Zeichner, prolonged elimination of the virus in symptomatic individuals in combination with viral elimination in asymptomatic individuals, including children, would make contact tracing and other public health measures less effective to mitigate viral spread. “

In light of what has been expressed so far, the need to stay at home is clear, everyone, even and especially children. If the institutions make different decisions, also in consideration of the possible psychological and emotional stress to which the children are subjected in emergency conditions, it will be necessary to develop precise protocols that the parents take responsibility for following.

Sandra Mazzoli, PhD

Laurea Degree in Biology. Specialized in Microbiology at the University of Pisa. Currently Retired.

She has been the Director of Sexually Transmitted Disease Center, Santa Maria Annunziata Hospital, Firenze, Italy. Contract Professor of Clinical Microbiology, at the University La Sapienza, Rome, and Contract Professor of Clinical and Applied Microbiology at the University of Florence. Visiting professor in several world Universities.

Studies on Chlamydia infections. HIV in Africa and Italy, Mucosal immunology and secretory IgA, Virus and cancer, Herpes and HPV infections, Cytokines, Biofilm in prostate and urinary infections.

She is the author of several scientific papers on HIV, HPV and Chlamydia infections, mucosal Immunology in Chlamydia and HIV infection, HPV and cancers, biofilm infections, cytokines in viral and bacterial endocellular infections and cancer. The most prestigious paper was published on the scientific paper “Nature Medicine”, HIV-specific mucosal and cellular immunity in HIV-seronegative partners of HIV-seropositive individuals.

Nov. 1997, about the discovery of antibodies, IgA, specific to HIV in seronegative subjects repeatedly exposed to the virus; other works, mainly concerning HIV infection, were published in Immunology Letters, International Journal of Cancer, Journal Infectious Diseases;  in the American Heart Journal, about Chlamydiae and myocardial infarction. Melanoma Research, Oncology Report, Clin Exp Metastasis, on cancer topics; Journal of Urology, European Urology, World J. of Urology, BJU International, Investigative and Clinical  Urology, International  J. Antimicrob Agents, J. Antimicrobial Chemotherapy.; J. Andrology, Clinical Infectious  Disease,  Pathogens, J. Infectious Disease, J. Sexual Medicine,  J. of Pathogens, BMC Public Health and other Journals on bacterial and viral infections.

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