Rhino-enteroviruses, particularly enterovirus strain D68 (EV-D68), have been associated with severe respiratory distress in children. The goal of this study was to compare the long-term outcomes of children with EV-D68 infection to that of children with other enterovirus / rhinovirus.

Nasopharyngeal swabs from 174 children presenting with respiratory distress were tested by PCR for respiratory viruses. The primary outcome was diagnosis of a chronic respiratory condition within the follow-up period. Admission to intensive care, and length of stay were recorded. Odds ratios were determined using multinomial logistic regression.

During 5 years of follow-up, the crude odds of diagnosis with a chronic respiratory condition were significantly more likely in EV-D68 cases (OR: 1.95, 95% CI: 1.02, 3.82), but failed to remain significant after adjusting for a past history of asthma. Upon admission for a primary concern of asthma, length of stay both in hospital and intensive care were significantly longer in EV-D68 cases (OR: 2.10 [95% CI: 1.56, 2.82, p < 0.001]) and (OR: 5.18 [95% CI: 1.90, 6.28, p < 0.001]), respectively. After adjustment for a history of asthma, EV-D68 cases had significantly longer length of stay in hospital, admitted for 1.94 days for each day that controls were admitted (95% CI: 1.40, 2.68). In admissions to intensive care, EV-D68 cases spent 2.74 days for each day of admission in controls (95% CI: 1.62, 4.97, p < 0.001).

Ours is first study to assess prognostic respiratory outcomes of patients infected with EV-D68 in childhood. Our study finds that EV-D68 cases were significantly more likely be hospitalized for longer than other enterovirus/rhinovirus controls in subsequent admissions for respiratory distress. Need for intensive care was significantly longer in EV-D68 infections. Our next steps will be validation in a larger sample size.

Young children are at high risk for developing complications of influenza, as well as severe clinical presentation of disease. Vaccination provides direct protection and reduces symptom severity in breakthrough infections. We assessed whether adjuvanted trivalent seasonal influenza vaccine is associated with symptom severity in children who developed laboratory-confirmed influenza, as compared to children who received quadrivalent inactivated influenza.

A cluster randomized controlled trial of influenza vaccines in Canadian Hutterite colonies was conducted from the 2016–2017 to the 2018–2019 influenza season. Children were vaccinated with either quadrivalent inactivated influenza vaccine (QIV), or the MF59 adjuvanted trivalent influenza vaccine (aTIV). We assessed children who developed PCR-confirmed influenza infection for symptom severity outcomes using multivariable generalized negative binomial regression.

Among vaccinated children, 49 infections were observed across 1779 person-days. Vaccine formulation (aTIV vs QIV) was not significantly associated with composite symptom outcomes, including total number of symptoms or total duration of symptom presentation (p > 0.05 for all outcomes). Receipt of aTIV vaccination was significantly associated with attenuation of fever, with an estimated 74% reduction in fever severity. In influenza A type infections, adjuvanted vaccination was significantly associated with reduced systemic symptoms (incidence rate ratios: 0.16, 95% confidence intervals: 0.03, 0.64, p = 0.01). No associations were observed between vaccine formulation and symptom severity in influenza B infections.

In vaccinated children who develop an influenza infection, vaccine formulation was associated with attenuated fever severity, leading to reduced systemic symptoms. In influenza A infections, adjuvanted vaccination was significantly associated with reduced systemic symptoms.

Clinical Trials Registry: NCT02871206