tetano
Editor, Senior Moderator
Clin Infect Dis. 2018 Jun 9. doi: 10.1093/cid/ciy487. [Epub ahead of print]
[h=1]Antibody responses to influenza A/H1N1pdm09 virus after pandemic and seasonal influenza vaccination in healthcare workers: a five-year follow-up study.[/h] Trieu MC[SUP]1,[/SUP][SUP]2[/SUP], Jul-Larsen ?[SUP]1,[/SUP][SUP]2[/SUP], S?vik M[SUP]3[/SUP], Madsen A[SUP]1[/SUP], N?stbakken JK[SUP]1[/SUP], Zhou F[SUP]1,[/SUP][SUP]2[/SUP], Skrede S[SUP]3,[/SUP][SUP]4[/SUP], Cox RJ[SUP]1,[/SUP][SUP]2,[/SUP][SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background:[/h] The 2009 influenza pandemic was caused by A/H1N1pdm09 virus, which was subsequently included in the seasonal vaccine as the A/H1N1 strain up to 2016/17. This provided a unique opportunity to investigate the antibody response to H1N1pdm09 over time.
[h=4]Methods:[/h] Healthcare workers (HCWs) were immunized with the AS03-adjuvanted H1N1pdm09 vaccine in 2009 (N=250), and subsequently vaccinated with seasonal vaccines containing H1N1pdm09 for 4 seasons (repeated group), <4 seasons (occasional group), or received no further vaccinations (single group). Blood samples were collected at 21-days, 3-, 6- and 12-months after each vaccination or annually (pre-season) from 2010 in the single group. The H1N1pdm09-specific antibodies were measured by the hemagglutination inhibition (HI) assay.
[h=4]Results:[/h] Pandemic vaccination robustly induced HI antibodies that persisted above the 50% protective threshold (HI titers ≥40) over 12-months post-vaccination. Previous seasonal vaccination and the duration of adverse events after pandemic vaccination influenced the decision to vaccinate in subsequent seasons. During 2010/11-2013/14, antibodies were boosted after each seasonal vaccination, although no significant difference was observed between the repeated and occasional groups. In the single group without seasonal vaccination, 32% of HCWs seroconverted (≥4 fold-increase HI titers) during the four subsequent years, most of whom had HI titers <40 prior to seroconversion. When excluding these seroconverted HCWs, HI titers gradually declined from 12- to 60-months post-pandemic vaccination.
[h=4]Conclusions:[/h] Pandemic vaccination elicited durable antibodies, supporting the incorporation of adjuvant. Our findings support the current recommendation of annual influenza vaccination in HCWs.
PMID: 29893797 DOI: 10.1093/cid/ciy487
[h=1]Antibody responses to influenza A/H1N1pdm09 virus after pandemic and seasonal influenza vaccination in healthcare workers: a five-year follow-up study.[/h] Trieu MC[SUP]1,[/SUP][SUP]2[/SUP], Jul-Larsen ?[SUP]1,[/SUP][SUP]2[/SUP], S?vik M[SUP]3[/SUP], Madsen A[SUP]1[/SUP], N?stbakken JK[SUP]1[/SUP], Zhou F[SUP]1,[/SUP][SUP]2[/SUP], Skrede S[SUP]3,[/SUP][SUP]4[/SUP], Cox RJ[SUP]1,[/SUP][SUP]2,[/SUP][SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background:[/h] The 2009 influenza pandemic was caused by A/H1N1pdm09 virus, which was subsequently included in the seasonal vaccine as the A/H1N1 strain up to 2016/17. This provided a unique opportunity to investigate the antibody response to H1N1pdm09 over time.
[h=4]Methods:[/h] Healthcare workers (HCWs) were immunized with the AS03-adjuvanted H1N1pdm09 vaccine in 2009 (N=250), and subsequently vaccinated with seasonal vaccines containing H1N1pdm09 for 4 seasons (repeated group), <4 seasons (occasional group), or received no further vaccinations (single group). Blood samples were collected at 21-days, 3-, 6- and 12-months after each vaccination or annually (pre-season) from 2010 in the single group. The H1N1pdm09-specific antibodies were measured by the hemagglutination inhibition (HI) assay.
[h=4]Results:[/h] Pandemic vaccination robustly induced HI antibodies that persisted above the 50% protective threshold (HI titers ≥40) over 12-months post-vaccination. Previous seasonal vaccination and the duration of adverse events after pandemic vaccination influenced the decision to vaccinate in subsequent seasons. During 2010/11-2013/14, antibodies were boosted after each seasonal vaccination, although no significant difference was observed between the repeated and occasional groups. In the single group without seasonal vaccination, 32% of HCWs seroconverted (≥4 fold-increase HI titers) during the four subsequent years, most of whom had HI titers <40 prior to seroconversion. When excluding these seroconverted HCWs, HI titers gradually declined from 12- to 60-months post-pandemic vaccination.
[h=4]Conclusions:[/h] Pandemic vaccination elicited durable antibodies, supporting the incorporation of adjuvant. Our findings support the current recommendation of annual influenza vaccination in HCWs.
PMID: 29893797 DOI: 10.1093/cid/ciy487