While in Italy the pediatric vaccination started just under a month (673 thousand children between 5 and 11 who received at least a dose equal to 18% of the audience), United States (which started in November) the first substantial data on the safety of the anti Covid compound arrive. An analysis conducted in the US by the CDCs (Centers for disease control and prevention) on the reports received by the surveillance system Vaers (Vaccine Adverse Event Reporting System) in relazione ad over 8.7 million vaccinations of children between the ages of 5 and 11.
The surveillance system has collected just over 4,000 reports of adverse events, of which 97.6% mild. Among the 100 serious adverse events, the most frequent were high fever, vomiting, convulsions. Eleven cases of myocarditis were verified, seven resolved and four in the process of being resolved at the time of closing the report. Two deaths, two girls of 5 and 6 years of age with complicated medical histories and in conditions of extreme fragility before vaccination. The studies carried out, before the authorization of the regulatory bodies, revealed the population of 5-11 years “90.7% efficacy in reducing symptomatic Sars Cov 2 infections compared to placebo and the non-inferiority of the immunological response compared to that observed in the population 16-25 years old “.
Meanwhile, a British research group hypothesizes why the very young are less susceptible to Sars Cov 2 infection. The researchers compared antibody and cellular immunity in children aged 3 to 11 and adults, some of them with a previous coronavirus infection. While the antibody level and the neutralization capacity of the viral variants was found to be comparable between children and adults, the response of T cells specific to the Spike protein (the main mechanism the virus uses to infect target cells) was more than doubled in children, and was also detected in many HIV-negative children, indicating a cross-reactive response resulting from previous infections with seasonal coronaviruses. Furthermore, the children maintained antibody and cellular responses even 6 months after infection, while a decline was found in adults.
Another factor that could help explain the lower severity of infections in children – which increased with the appearance of the Omicron variant – could be the antibody response. Researchers from the Presbyterian hospital Weill Cornell di New York examined almost 32,000 serologies carried out between April and August 2020, finding fairly similar rates of seroprevalence between children and adults (respectively 17% and 19%). When the sera were analyzed, the scientists realized that the antibody levels in children were negatively correlated with age: in children under the age of 10 the average level of IgG was in fact double that of adolescents (11 -19 years), who in turn had an IgG level more than double that of young adults between the ages of 19 and 24.