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Clin Infect Dis. 2017 Mar 17. doi: 10.1093/cid/cix209. [Epub ahead of print]
Repeated vaccination does not appear to impact on influenza vaccine effectiveness against hospitalisation with confirmed influenza.
Cheng AC1, Macartney KK2, Waterer GW3, Kotsimbos T4, Kelly PM5, Blyth CC6; FluCAN Investigators.
Author information
Abstract
Background:
Annual influenza vaccine is recommended for those at greatest risk of severe influenza infection. Recent reports of a negative impact of serial influenza vaccination on vaccine effectiveness raises concerns about the recommendation for annual influenza vaccines, particularly in those at greatest risk.
Methods:
The Influenza Complications Alert Network (FluCAN) is an Australian hospital-based sentinel surveillance program. In this observational study, cases were defined as subjects >9 years admitted with influenza confirmed by PCR. Controls were subjects with acute respiratory illness testing negative for influenza. Propensity scores were used to adjust for the likelihood of being vaccinated. Vaccine effectiveness (VE) was 1 -- adjusted odds ratio of vaccination in cases compared with test-negative controls.
Results:
Over 2010-2015, 6223 cases and 6505 controls were hospitalized with confirmed influenza and influenza-test negative ARI respectively. Following stratification by quintile of propensity score, site and year, VE was estimated to be 43% (95%CI: 37%, 49%) overall. VE was estimated to be 51% (95% CI: 45%. 57%) in those vaccinated in both the current and previous season, compared with 33%, (95% CI: 17%, 47%) vaccinated in the current season only and 35%, (95% CI: 21%, 46%) in the previous season only. Similar results were observed for influenza A/H1N1, A/H3N2 and influenza B strains.
Conclusions:
Vaccination in both the current and previous seasons was associated with a higher VE against hospitalisation with influenza than vaccination in either single season. These findings reinforce current recommendations for annual influenza vaccination, particularly those at greatest risk of influenza disease.
KEYWORDS:
Clinical Effectiveness; hospitalisation; influenza; influenza vaccine
PMID: 28329167 DOI: 10.1093/cid/cix209
Repeated vaccination does not appear to impact on influenza vaccine effectiveness against hospitalisation with confirmed influenza.
Cheng AC1, Macartney KK2, Waterer GW3, Kotsimbos T4, Kelly PM5, Blyth CC6; FluCAN Investigators.
Author information
Abstract
Background:
Annual influenza vaccine is recommended for those at greatest risk of severe influenza infection. Recent reports of a negative impact of serial influenza vaccination on vaccine effectiveness raises concerns about the recommendation for annual influenza vaccines, particularly in those at greatest risk.
Methods:
The Influenza Complications Alert Network (FluCAN) is an Australian hospital-based sentinel surveillance program. In this observational study, cases were defined as subjects >9 years admitted with influenza confirmed by PCR. Controls were subjects with acute respiratory illness testing negative for influenza. Propensity scores were used to adjust for the likelihood of being vaccinated. Vaccine effectiveness (VE) was 1 -- adjusted odds ratio of vaccination in cases compared with test-negative controls.
Results:
Over 2010-2015, 6223 cases and 6505 controls were hospitalized with confirmed influenza and influenza-test negative ARI respectively. Following stratification by quintile of propensity score, site and year, VE was estimated to be 43% (95%CI: 37%, 49%) overall. VE was estimated to be 51% (95% CI: 45%. 57%) in those vaccinated in both the current and previous season, compared with 33%, (95% CI: 17%, 47%) vaccinated in the current season only and 35%, (95% CI: 21%, 46%) in the previous season only. Similar results were observed for influenza A/H1N1, A/H3N2 and influenza B strains.
Conclusions:
Vaccination in both the current and previous seasons was associated with a higher VE against hospitalisation with influenza than vaccination in either single season. These findings reinforce current recommendations for annual influenza vaccination, particularly those at greatest risk of influenza disease.
KEYWORDS:
Clinical Effectiveness; hospitalisation; influenza; influenza vaccine
PMID: 28329167 DOI: 10.1093/cid/cix209