Refine
Has Fulltext
- yes (12)
Is part of the Bibliography
- yes (12) (remove)
Year of publication
Document Type
- Journal article (12)
Language
- English (12) (remove)
Keywords
- influenza (4)
- children (3)
- Germany (2)
- burden (2)
- infection (2)
- vaccination (2)
- CVID (1)
- Children (1)
- Coverage (1)
- Deutschland (1)
- Disease severity (1)
- Epidemiology (1)
- European Society for Immunodeficiencies (ESID) (1)
- European experience (1)
- German PID-NET registry (1)
- Grippe (1)
- Hospitalisation (1)
- Hospitalization (1)
- ICD-10 (1)
- IgG (1)
- IgG substitution therapy (1)
- Incidence (1)
- Infectious disease (1)
- Influenza (1)
- Medizin (1)
- NADPH oxidase (1)
- P67(PHOX) (1)
- PID prevalence (1)
- Paediatric (1)
- Pediatric (1)
- RSV-A ON1 (1)
- Respiratory tract infection (1)
- Surveillance (1)
- United States (1)
- Vaccination (1)
- Varicella (1)
- antibiotic use (1)
- antimicrobial resistance (1)
- antimicrobial stewardship (1)
- coverage (1)
- disease (1)
- disease severity (1)
- efficacy (1)
- epidemiology (1)
- gene (1)
- general practitioner (1)
- healthcare costs (1)
- hospitalization (1)
- hospitalizations (1)
- immunology (1)
- infectious diseases management (1)
- intensive care (1)
- interferon gamma (1)
- knowledge (1)
- live-attenuated influenza vaccine (1)
- measles (1)
- metanalysis (1)
- mutation (1)
- outpatient (1)
- pediatric (1)
- pediatrician (1)
- post-pandemic (1)
- primary care (1)
- primary immunodeficiency (PID) (1)
- prophylaxis (1)
- recommendations (1)
- region (1)
- registry for primary immunodeficiency (1)
- seasonal influenza (1)
- surveillance (1)
- survey (1)
- transmission model (1)
- varicella (1)
- young children (1)
Background
Influenza virus infections in immunologically naïve children (primary infection) may be more severe than in children with re-infections who are already immunologically primed. We compared frequency and severity of influenza virus primary and re-infections in pre-school children requiring outpatient treatment.
Methods
Influenza-unvaccinated children 1–5 years of age presenting at pediatric practices with febrile acute respiratory infection < 48 h after symptom onset were enrolled in a prospective, cross-sectional, multicenter surveillance study (2013–2015). Influenza types/subtypes were PCR-confirmed from oropharyngeal swabs. Influenza type/subtype-specific IgG antibodies serving as surrogate markers for immunological priming were determined using ELISA/hemagglutination inhibition assays. The acute influenza disease was defined as primary infection/re-infection by the absence/presence of influenza type-specific immunoglobulin G (IgG) and, in a second approach, by the absence/presence of subtype-specific IgG. Socio-demographic and clinical data were also recorded.
Results
Of 217 influenza infections, 178 were due to influenza A (87 [49%] primary infections, 91 [51%] re-infections) and 39 were due to influenza B (38 [97%] primary infections, one [3%] re-infection). Children with “influenza A primary infections” showed fever with respiratory symptoms for a shorter period than children with “influenza A re-infections” (median 3 vs. 4 days; age-adjusted p = 0.03); other disease characteristics were similar. If primary infections and re-infections were defined based on influenza A subtypes, 122 (87%) primary infections (78 “A(H3N2) primary infections”, 44 “A(H1N1)pdm09 primary infections”) and 18 (13%) re-infections could be classified (14 “A(H3N2) re-infections” and 4 “A(H1N1)pdm09 re-infections”). Per subtype, primary infections and re-infections were of similar disease severity. Children with re-infections defined on the subtype level usually had non-protective IgG titers against the subtype of their acute infection (16 of 18; 89%). Some patients infected by one of the influenza A subtypes showed protective IgG titers (≥ 1:40) against the other influenza A subtype (32/140; 23%).
Conclusions
Pre-school children with acute influenza A primary infections and re-infections presented with similar frequency in pediatric practices. Contrary to expectation, severity of acute “influenza A primary infections” and “influenza A re-infections” were similar. Most “influenza A re-infections” defined on the type level turned out to be primary infections when defined based on the subtype. On the subtype level, re-infections were rare and of similar disease severity as primary infections of the same subtype. Subtype level re-infections were usually associated with low IgG levels for the specific subtype of the acute infection, suggesting only short-time humoral immunity induced by previous infection by this subtype. Overall, the results indicated recurring influenza virus infections in this age group and no or only limited heterosubtypic antibody-mediated cross-protection.