COVID-19 and the differences in physiological background between children and adults and their clinical consequences.

The SARS-CoV-2 pandemic has indeed been one of the most significant problems facing the world in the last decade. It has affected (directly or indirectly) the entire population and all age groups. Children have accounted for 1.7 % to 2 % of the diagnosed cases of COVID-19. COVID-19 in children is usually associated with a mild course of the disease and a better survival rate than in adults. In this review, we investigate the different mechanisms which underlie this observation. Generally, we can say that the innate immune response of children is strong because they have a trained immunity, allowing the early control of infection at the site of entry. Suppressed adaptive immunity and a dysfunctional innate immune response is seen in adult patients with severe infections but not in children. This may relate to immunosenescence in the elderly. Another proposed factor is the different receptors for SARS-CoV-2 and their differences in expression between these age groups. In infants and toddlers, effective immune response to viral particles can be modulated by the pre-existing non-specific effect of live attenuated vaccines on innate immunity and vitamin D prophylaxis. However, all the proposed mechanisms require verification in larger cohorts of patients. Our knowledge about SARS-CoV-2 is still developing.

Paediatric pneumococcal disease in Central Europe.

Streptococcus pneumoniae causes considerable global paediatric morbidity and mortality, despite the availability of safe and effective pneumococcal conjugate vaccines (PCVs). To justify the introduction of PCVs, accurate information on the burden of disease is required. Here, we present an appraisal of the pneumococcal epidemiological situation in 11 Central European countries. The data are based on study findings presented at the 12th Central European Vaccine Advisory Group (CEVAG) meeting, held on 21-22 May 2010 in Sofia, Bulgaria, and a literature review of the PubMed database using the search terms 'pneumococcal' or 'Streptococcus pneumoniae', in combination with 'otitis media', 'pneumonia', 'meningitis' or 'bacteraemia/sepsis', and '[Central European country name]'. The incidence of pneumococcal disease appears to be lower in Central Europe than previously reported for Europe as a whole, with the highest risk in infants aged 0-2 years. The fatality rates in the under fives from invasive infections are up to 40%. A paucity of comprehensive country-specific data on pneumococcal disease burden arises from the lack of homogenous surveillance programmes. Standardised, active surveillance systems are required for the accurate evaluation of the pneumococcal disease burden in the region. Only then can the need for vaccination be addressed.

Two cases of severe invasive infections in children caused by Streptococcus pneumoniae serotype 14--case report.

Two cases are presented of severe pneumococcal infections in infants caused by serotype 14 Streptococcus pneumoniae. The first case--meningitis--caused by S. pneumoniae (pneumococcus) with low-level penicillin susceptibility has developed from acute otitis media and resulted in fatal outcome. The second one--an immunocompromised child presenting recurrent otitis and chronic mastoiditis--developed into pneumococcal pneumonia. Both cases demonstrate the extreme importance of a relevant initial treatment of localized pneumococcal infections, preventing the development of generalized infection. Amoxicillin (an oral treatment option in both upper and lower respiratory tract infections caused also by Pneumococcus strains with low-level penicillin susceptibility due to its beneficial pharmacokinetics and pharmacodynamics) was not used in either case.