Influenza vaccine effectiveness among 50–64-year-old persons during a season of poor antigenic match between vaccine and circulating influenza virus strains: Colorado, United States, 2003–2004

Abstract Background Influenza causes significant morbidity and mortality and stresses hospital resources during periods of increased circulation. We evaluated the effectiveness of the 2019-2020 influenza vaccine against influenza-associated hospitalizations in the United States. Methods We included adults hospitalized with acute respiratory illness at 14 hospitals and tested for influenza viruses by reserve transcription polymerase chain reaction. Vaccine effectiveness (VE) was estimated by comparing the odds of current-season influenza vaccination in test-positive influenza cases versus test-negative controls, adjusting for confounders. VE was stratified by age and major circulating influenza types along with A(H1N1)pdm09 genetic subgroups. Results 3116 participants were included, including 18% (553) influenza-positive cases. Median age was 63 years. Sixty-seven percent (2079) received vaccination. Overall adjusted VE against influenza viruses was 41% (95% confidence interval [CI]: 27-52). VE against A(H1N1)pdm09 viruses was 40% (95% CI: 24-53) and 33% against B viruses (95% CI: 0-56). Of the two major A(H1N1)pdm09 subgroups (representing 90% of sequenced H1N1 viruses), VE against one group (5A+187A,189E) was 59% (95% CI: 34-75) whereas no significant VE was observed against the other group (5A+156K) [-1%, 95% CI: -61-37]. Conclusions In a primarily older population, influenza vaccination was associated with a 41% reduction in risk of hospitalized influenza illness.

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Influenza Vaccine Effectiveness in the United States During the 2016–2017 Season

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx163.1151 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S451-S452

Author(s):

Brendan Flannery ◽

Jessie Chung ◽

Arnold S Monto ◽

Emily T Martin ◽

Edward Belongia ◽

...

Keyword(s):

United States ◽

Influenza Vaccine ◽

The United States ◽

Vaccine Effectiveness

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Influenza vaccine effectiveness among patients with high-risk medical conditions in the United States, 2012–2016

Vaccine ◽

10.1016/j.vaccine.2018.10.093 ◽

2018 ◽

Vol 36 (52) ◽

pp. 8047-8053 ◽

Cited By ~ 9

Author(s):

Mei Shang ◽

Jessie R. Chung ◽

Michael L. Jackson ◽

Lisa A. Jackson ◽

Arnold S. Monto ◽

...

Keyword(s):

United States ◽

High Risk ◽

Influenza Vaccine ◽

The United States ◽

Vaccine Effectiveness ◽

Medical Conditions

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Effects of Prior Influenza Exposure on Immunogenicity of Influenza Vaccine

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa181 ◽

2020 ◽

Author(s):

Jia-Qian Cao ◽

Peng-Fei Jin ◽

Zhao-Zhun Zeng ◽

Li Zhang ◽

Fan-Yue Meng ◽

...

Keyword(s):

Clinical Trials ◽

Influenza Virus ◽

Immune Responses ◽

Influenza Vaccine ◽

Hemagglutination Inhibition ◽

Cross Reactivity ◽

Vaccine Effectiveness ◽

Prior Exposure ◽

Post Vaccination ◽

Blood Samples

Abstract Background To investigate effects of prior influenza exposure on vaccine-elicited humor immune responses to circulating influenza variants. Method We randomly selected 360 participants in previous clinical trials stratified by age. Blood samples before and 28 days after vaccination were collected and tested by hemagglutination-inhibition tests against both vaccine strains and circulating variants during the 2015–2016 influenza seasons in China. The antigenic map was plotted and antigenic distance was calculated. Results Subjects with H1-priming had higher cross-reactive antibodies titers against A/JiangsuTinghu/11019/2015(H3N2) compared with subjects with B-priming did (Padjusted=0.038). Subjects with H1-priming also had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming did (Padjusted=0.036). Nevertheless, subjects with no H1 and B-priming had higher cross-reactive antibodies titers against A/Jiangsu Qinhuai/11059/2015(H3N2) than subjects with both H1 and B priming did (Padjusted=0.012). Antigenic distance was well-matched with serological results. Besides, age-specific differences in human post-vaccination responses against the identical circulating strain was noted. And children had most cross-reactive response to both H3N2 and B-yamagata subtypes. Conclusion Our results suggest that prior exposure to H1 or B influenza virus may influence cross-reactivity of H3-specific post-vaccination responses and consequently could influence the vaccine effectiveness. Our findings also support that there are age-specific differences in human post-vaccination responses.

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150. Relative Effectiveness of High-Dose and Standard-Dose Influenza Vaccine Against Influenza-Related Hospitalization Among Older Adults—United States, 2015–2017

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy209.020 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S10-S10

Author(s):

Joshua Doyle ◽

Lauren Beacham ◽

Elif Alyanak ◽

Manjusha Gaglani ◽

Emily T Martin ◽

...

Keyword(s):

United States ◽

Older Adults ◽

Influenza Vaccine ◽

Influenza A ◽

Standard Dose ◽

Relative Effectiveness ◽

The United States ◽

Vaccine Effectiveness ◽

High Dose ◽

Research Grant

Abstract Background Seasonal influenza causes substantial morbidity and mortality, and older adults are disproportionately affected. Newer vaccines have been developed for use in people 65 years and older, including a trivalent inactivated vaccine with a 4-fold higher dose of antigen (IIV-HD). In recent years, the use of IIV-HD has increased sufficiently to evaluate its effectiveness compared with standard-dose inactivated influenza vaccines (IIV-SD). Methods Hospitalized patients with acute respiratory illness were enrolled in an observational vaccine effectiveness study at 8 hospitals in 4 states participating in the United States Hospitalized Adult Influenza Vaccine Effectiveness Network during the 2015–2016 and 2016–2017 influenza seasons. Predominant influenza A virus subtypes were H1N1 and H3N2, respectively, during these seasons. All enrolled patients were tested for influenza virus with polymerase chain reaction. Receipt and type of influenza vaccine was determined from electronic records and chart review. Odds of laboratory-confirmed influenza were compared among vaccinated and unvaccinated patients. Relative odds of laboratory-confirmed influenza were determined for patients who received IIV-HD or IIV-SD, and adjusted for potential confounding variables via logistic regression. Results Among 1,744 enrolled patients aged ≥ 65 years, 1,105 (63%) were vaccinated; among those vaccinated, 621 (56%) received IIV-HD and 484 (44%) received IIV-SD. Overall, 315 (18%) tested positive for influenza, including 97 (6%) who received IIV-HD, 86 (5%) who received IIV-SD, and 132 (8%) who were unvaccinated. Controlling for age, race, sex, enrollment site, date of illness, index of comorbidity, and influenza season, the adjusted odds of influenza among patients vaccinated with IIV-HD vs. IIV-SD were 0.72 (P = 0.06, 95% CI: 0.52 to 1.01). Conclusion Comparison of high-dose vs. standard-dose vaccine effectiveness during 2 recent influenza seasons (1 H1N1 and 1 H3N2-predominant) suggested relative benefit (nonsignificant) of high-dose influenza vaccine in protecting against influenza-associated hospitalization among persons aged 65 years and older; additional years of data are needed to confirm this finding. Disclosures H. K. Talbot, sanofi pasteur: Investigator, Research grant. Gilead: Investigator, Research grant. MedImmune: Investigator, Research grant. Vaxinnate: Safety Board, none. Seqirus: Safety Board, none.

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