tetano
Editor, Senior Moderator
Clin Infect Dis. 2018 Dec 3. doi: 10.1093/cid/ciy1009. [Epub ahead of print]
[h=1]The Impact of Prior Season Vaccination on Subsequent Influenza Vaccine Effectiveness (VE) to Prevent Influenza-Related Hospitalizations over Four Influenza Seasons in Canada.[/h] Nichols MK[SUP]1[/SUP], Andrew MK[SUP]1[/SUP], Ye L[SUP]1[/SUP], Hatchette TF[SUP]1[/SUP], Ambrose A[SUP]1[/SUP], Boivin G[SUP]2[/SUP], Bowie W[SUP]3[/SUP], Santos GD[SUP]4[/SUP], Elsherif M[SUP]1[/SUP], Green K[SUP]5[/SUP], Haguinet F[SUP]6[/SUP], Katz K[SUP]7[/SUP], Leblanc J[SUP]1[/SUP], Loeb M[SUP]8[/SUP], MacKinnon-Cameron D[SUP]1[/SUP], McCarthy A[SUP]9[/SUP], McElhaney JE[SUP]10[/SUP], McGeer A[SUP]5[/SUP], Powis J[SUP]11[/SUP], Richardson D[SUP]12[/SUP], Semret M[SUP]13[/SUP], Sharma R[SUP]14[/SUP], Shinde V[SUP]15[/SUP], Smyth D[SUP]16[/SUP], Trottier S[SUP]2[/SUP], Valiquette L[SUP]17[/SUP], Webster D[SUP]18[/SUP], McNeil SA[SUP]1[/SUP]; Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN).
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background:[/h] Recent studies have demonstrated the possibility of negative associations between prior influenza vaccines and subsequent influenza vaccine effectiveness (VE), depending on season and strain. We investigated this association over 4 consecutive influenza seasons (2011/2012-2014/2015) in Canada.
[h=4]Methods:[/h] Using a matched test-negative design, laboratory-confirmed influenza cases and matched test-negative controls admitted to hospitals were enrolled. Patients were stratified into four groups according to influenza vaccine history (not vaccinated current and prior season [referent], vaccinated prior season only, vaccinated current season only, and vaccinated both current and prior season). Conditional logistic regression was used to estimate VE; prior vaccine impact was assessed each season for overall effect and effect stratified by age (<65y, ≥65y) and type/subtype (A/H1N1, A/H3N2, influenza B). ClinicalTrials.gov Identifier: NCT01517191.
[h=4]Results:[/h] Overall, mainly non-significant associations between prior influenza vaccine and subsequent VE were observed. Trends of non-significant decreased VE among patients repeatedly vaccinated in both the prior and current season relative to the current season only were observed in the A/H3N2 dominant seasons of 2012/2013 and 2014/2015. Conversely, in 2011/2012, during which B viruses circulated, and in 2013/2014, when A/H1N1 circulated, being vaccinated in both seasons tended to result in a high VE in the current season against the dominant circulating subtype.
[h=4]Conclusions:[/h] Prior vaccine impact on subsequent VE among Canadian inpatients was mainly non-significant. Even in circumstances where we observed a trend of negative impact, being repeatedly vaccinated was still more effective than not receiving the current season's vaccine. These findings favour continuation of annual influenza vaccination recommendations, particularly in older adults.
PMID: 30508064 DOI: 10.1093/cid/ciy1009
[h=1]The Impact of Prior Season Vaccination on Subsequent Influenza Vaccine Effectiveness (VE) to Prevent Influenza-Related Hospitalizations over Four Influenza Seasons in Canada.[/h] Nichols MK[SUP]1[/SUP], Andrew MK[SUP]1[/SUP], Ye L[SUP]1[/SUP], Hatchette TF[SUP]1[/SUP], Ambrose A[SUP]1[/SUP], Boivin G[SUP]2[/SUP], Bowie W[SUP]3[/SUP], Santos GD[SUP]4[/SUP], Elsherif M[SUP]1[/SUP], Green K[SUP]5[/SUP], Haguinet F[SUP]6[/SUP], Katz K[SUP]7[/SUP], Leblanc J[SUP]1[/SUP], Loeb M[SUP]8[/SUP], MacKinnon-Cameron D[SUP]1[/SUP], McCarthy A[SUP]9[/SUP], McElhaney JE[SUP]10[/SUP], McGeer A[SUP]5[/SUP], Powis J[SUP]11[/SUP], Richardson D[SUP]12[/SUP], Semret M[SUP]13[/SUP], Sharma R[SUP]14[/SUP], Shinde V[SUP]15[/SUP], Smyth D[SUP]16[/SUP], Trottier S[SUP]2[/SUP], Valiquette L[SUP]17[/SUP], Webster D[SUP]18[/SUP], McNeil SA[SUP]1[/SUP]; Serious Outcomes Surveillance (SOS) Network of the Canadian Immunization Research Network (CIRN).
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background:[/h] Recent studies have demonstrated the possibility of negative associations between prior influenza vaccines and subsequent influenza vaccine effectiveness (VE), depending on season and strain. We investigated this association over 4 consecutive influenza seasons (2011/2012-2014/2015) in Canada.
[h=4]Methods:[/h] Using a matched test-negative design, laboratory-confirmed influenza cases and matched test-negative controls admitted to hospitals were enrolled. Patients were stratified into four groups according to influenza vaccine history (not vaccinated current and prior season [referent], vaccinated prior season only, vaccinated current season only, and vaccinated both current and prior season). Conditional logistic regression was used to estimate VE; prior vaccine impact was assessed each season for overall effect and effect stratified by age (<65y, ≥65y) and type/subtype (A/H1N1, A/H3N2, influenza B). ClinicalTrials.gov Identifier: NCT01517191.
[h=4]Results:[/h] Overall, mainly non-significant associations between prior influenza vaccine and subsequent VE were observed. Trends of non-significant decreased VE among patients repeatedly vaccinated in both the prior and current season relative to the current season only were observed in the A/H3N2 dominant seasons of 2012/2013 and 2014/2015. Conversely, in 2011/2012, during which B viruses circulated, and in 2013/2014, when A/H1N1 circulated, being vaccinated in both seasons tended to result in a high VE in the current season against the dominant circulating subtype.
[h=4]Conclusions:[/h] Prior vaccine impact on subsequent VE among Canadian inpatients was mainly non-significant. Even in circumstances where we observed a trend of negative impact, being repeatedly vaccinated was still more effective than not receiving the current season's vaccine. These findings favour continuation of annual influenza vaccination recommendations, particularly in older adults.
PMID: 30508064 DOI: 10.1093/cid/ciy1009