Background: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 breakthrou...Background: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 in-fections.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.Methods: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.Results: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.Conclusions: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.展开更多
文摘Background: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 in-fections.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.Methods: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.Results: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.Conclusions: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.
