scholarly journals Effects of Influenza Vaccination in the United States During the 2017–2018 Influenza Season

2019 ◽  
Vol 69 (11) ◽  
pp. 1845-1853 ◽  
Author(s):  
Melissa A Rolfes ◽  
Brendan Flannery ◽  
Jessie R Chung ◽  
Alissa O’Halloran ◽  
Shikha Garg ◽  
...  
Keyword(s):  
United States ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Influenza A ◽  
Influenza Season ◽  
Influenza Virus Infection ◽  
The United States ◽  
Influenza B ◽  
Medical Visits ◽  
Influenza A H1n1

Abstract Background The severity of the 2017–2018 influenza season in the United States was high, with influenza A(H3N2) viruses predominating. Here, we report influenza vaccine effectiveness (VE) and estimate the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the 2017–2018 influenza season. Methods We used national age-specific estimates of 2017–2018 influenza vaccine coverage and disease burden. We estimated VE against medically attended reverse-transcription polymerase chain reaction–confirmed influenza virus infection in the ambulatory setting using a test-negative design. We used a compartmental model to estimate numbers of influenza-associated outcomes prevented by vaccination. Results The VE against outpatient, medically attended, laboratory-confirmed influenza was 38% (95% confidence interval [CI], 31%–43%), including 22% (95% CI, 12%–31%) against influenza A(H3N2), 62% (95% CI, 50%–71%) against influenza A(H1N1)pdm09, and 50% (95% CI, 41%–57%) against influenza B. We estimated that influenza vaccination prevented 7.1 million (95% CrI, 5.4 million–9.3 million) illnesses, 3.7 million (95% CrI, 2.8 million–4.9 million) medical visits, 109 000 (95% CrI, 39 000–231 000) hospitalizations, and 8000 (95% credible interval [CrI], 1100–21 000) deaths. Vaccination prevented 10% of expected hospitalizations overall and 41% among young children (6 months–4 years). Conclusions Despite 38% VE, influenza vaccination reduced a substantial burden of influenza-associated illness, medical visits, hospitalizations, and deaths in the United States during the 2017–2018 season. Our results demonstrate the benefit of current influenza vaccination and the need for improved vaccines.

scholarly journals Effects of Influenza Vaccination in the United States During the 2018–2019 Influenza Season

2020 ◽  
Vol 71 (8) ◽  
pp. e368-e376 ◽  
Author(s):  
Jessie R Chung ◽  
Melissa A Rolfes ◽  
Brendan Flannery ◽  
Pragati Prasad ◽  
Alissa O’Halloran ◽  
...  
Keyword(s):  
United States ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Influenza Season ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Influenza Viruses ◽  
Monte Carlo Algorithm ◽  
Medical Visits ◽  
The Us

Abstract Background Multivalent influenza vaccine products provide protection against influenza A(H1N1)pdm09, A(H3N2), and B lineage viruses. The 2018–2019 influenza season in the United States included prolonged circulation of A(H1N1)pdm09 viruses well-matched to the vaccine strain and A(H3N2) viruses, the majority of which were mismatched to the vaccine. We estimated the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the season. Methods We used a mathematical model and Monte Carlo algorithm to estimate numbers and 95% uncertainty intervals (UIs) of influenza-associated outcomes prevented by vaccination in the United States. The model incorporated age-specific estimates of national 2018–2019 influenza vaccine coverage, influenza virus–specific vaccine effectiveness from the US Influenza Vaccine Effectiveness Network, and disease burden estimated from population-based rates of influenza-associated hospitalizations through the Influenza Hospitalization Surveillance Network. Results Influenza vaccination prevented an estimated 4.4 million (95%UI, 3.4 million–7.1 million) illnesses, 2.3 million (95%UI, 1.8 million–3.8 million) medical visits, 58 000 (95%UI, 30 000–156 000) hospitalizations, and 3500 (95%UI, 1000–13 000) deaths due to influenza viruses during the US 2018–2019 influenza season. Vaccination prevented 14% of projected hospitalizations associated with A(H1N1)pdm09 overall and 43% among children aged 6 months–4 years. Conclusions Influenza vaccination averted substantial influenza-associated disease including hospitalizations and deaths in the United States, primarily due to effectiveness against A(H1N1)pdm09. Our findings underscore the value of influenza vaccination, highlighting that vaccines measurably decrease illness and associated healthcare utilization even in a season in which a vaccine component does not match to a circulating virus.

scholarly journals Effectiveness of influenza vaccine in preventing medically-attended influenza virus infection in primary care, Israel, influenza seasons 2014/15 and 2015/16

2018 ◽  
Vol 23 (7) ◽  
Author(s):  
Hamutal Yaron-Yakoby ◽  
Hanna Sefty ◽  
Rakefet Pando ◽  
Rita Dichtiar ◽  
Mark A Katz ◽  
...  
Keyword(s):  
Primary Care ◽  
Influenza Virus ◽  
Influenza Vaccine ◽  
Influenza A ◽  
Influenza Season ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Influenza B ◽  
Negative Case ◽  
Influenza A H1n1

Introduction Influenza vaccine is recommended for the entire population in Israel. We assessed influenza vaccine effectiveness (VE) for the 2014/15 and 2015/16 seasons in Israel, for the first time. Methods: Combined nose and throat swab specimens were collected from patients with influenza-like illness (ILI) presenting to sentinel primary care clinics and tested for influenza virus by RT-PCR. VE of the trivalent inactivated vaccine (TIV) was assessed using test-negative case–control design. Results: During the 2014/15 season 1,142 samples were collected; 327 (28.6%) were positive for influenza, 83.8% A(H3N2), 5.8% A(H1N1)pdm09, 9.2% B and 1.2% A un-subtyped. Adjusted VE against all influenza viruses for this influenza season was −4.8% (95% confidence interval (CI): −54.8 to 29.0) and against influenza A(H3N2), it was −15.8% (95% CI: −72.8 to 22.4). For the 2015/16 season, 1,919 samples were collected; 853 (44.4%) were positive for influenza, 43.5% A(H1N1)pdm09, 57% B, 0.7% A(H3N2) and 11 samples positive for both A(H1N1)pdm09 and B. Adjusted VE against all influenza viruses for this influenza season was 8.8% (95% CI: −25.1 to 33.5), against influenza A(H1N1)pdm09, it was 32.3% (95% CI: (−4.3 to 56.1) and against influenza B, it was −2.2% (95% CI: (−47.0 to 29.0). Conclusions: Using samples from patients with ILI visiting sentinel clinics in Israel, we demonstrated the feasibility of influenza VE estimation in Israel.

scholarly journals The impact of the 2009 influenza A(H1N1) pandemic on attitudes of healthcare workers toward seasonal influenza vaccination 2010/11

2011 ◽  
Vol 16 (17) ◽  
Author(s):  
C Brandt ◽  
H F Rabenau ◽  
S Bornmann ◽  
R Gottschalk ◽  
S Wicker
Keyword(s):  
Medical Students ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Healthcare Workers ◽  
Influenza A ◽  
Influenza Season ◽  
University Hospital ◽  
The Public ◽  
Influenza A H1n1 ◽  
The Impact

The emergence of the influenza A(H1N1)2009 virus provided a major challenge to health services around the world. However, vaccination rates for the public and for healthcare workers (HCWs) have remained low. We performed a study to review the reasons put forward by HCWs to refuse immunisation with the pandemic vaccine in 2009/10 and characterise attitudes in the influenza season 2010/11 due to the emergence of influenza A(H1N1)2009. A survey among HCWs and medical students in the clinical phase of their studies was conducted, using an anonymous questionnaire, at a German university hospital during an influenza vaccination campaign. 1,366 of 3,900 HCWs (35.0%) were vaccinated in the 2010/11 influenza season. Of the vaccinated HCWs, 1,323 (96.9%) completed the questionnaire in addition to 322 vaccinated medical students. Of the 1,645 vaccinees who completed the questionnaire, 712 had not been vaccinated against the influenza A(H1N1)2009 virus in the 2009/10 season. The main reason put forward was the objection to the AS03 adjuvants (239/712, 33.6%). Of the HCWs and students surveyed, 270 of 1,645 (16.4%) stated that the pandemic had influenced their attitude towards vaccination in general. Many German HCWs remained unconvinced of the safety of the pandemic (adjuvanted) influenza vaccine. For this reason, effective risk communication should focus on educating the public and HCWs about influenza vaccine safety and the benefits of vaccination.

scholarly journals Lessons from the Past: Comparison of the Disease Burden of the Influenza A (H1N1) Pandemic 2009-10 and Seasonal Influenza 2010-2019 in the United States

2021 ◽  
Author(s):  
James A Koziol
Keyword(s):  
United States ◽  
Influenza A ◽  
Disease Burden ◽  
Seasonal Influenza ◽  
The United States ◽  
H1n1 Pandemic ◽  
Elderly Adults ◽  
The Past ◽  
Medical Visits ◽  
Influenza A H1n1

Abstract Background Annual influenza outbreaks constitute a major public health concern, both in the United States and worldwide. Comparisons of the health burdens of outbreaks might lead to the identification of specific at-risk populations, for whom public health resources should be marshaled appropriately and equitably. Methods We examined the disease burden of the 2009-10 influenza A (H1N1) pandemic relating to illnesses, medical visits, hospitalizations, and mortality, compared to influenza seasons 2010 to 2019, in the United States, as compiled by the Centers for Disease Control. Results With regard to seasonal influenza, rates of illnesses and medical visits were highest in infants aged 0–4 years, followed by adults aged 50–64 years. Rates of hospitalizations and deaths evinced a starkly different pattern, both dominated by elderly adults aged 65 and over. Youths aged 0 to 17 years were especially adversely affected by the H1N1 pandemic relative to hospitalizations and mortality compared to seasonal influenza; but curiously the opposite pattern was observed in elderly adults (aged 65 and older). Conclusions The disease burden of the 2009-10 influenza A pandemic was strikingly unlike that observed in the subsequent influenza seasons 2010 to 2019, in the United States: the past did not predict the future.

scholarly journals Anomalous influenza seasonality in the United States and the emergence of novel influenza B viruses

2021 ◽  
Vol 118 (5) ◽  
pp. e2012327118
Author(s):  
Rebecca K. Borchering ◽  
Christian E. Gunning ◽  
Deven V. Gokhale ◽  
K. Bodie Weedop ◽  
Arash Saeidpour ◽  
...  
Keyword(s):  
United States ◽  
Influenza A ◽  
Reproduction Number ◽  
Influenza Season ◽  
The United States ◽  
Influenza B ◽  
Relative Dynamics ◽  
2009 H1n1 ◽  
Kinetics Of ◽  
Early Activity

The 2019/2020 influenza season in the United States began earlier than any season since the 2009 H1N1 pandemic, with an increase in influenza-like illnesses observed as early as August. Also noteworthy was the numerical domination of influenza B cases early in this influenza season, in contrast to their typically later peak in the past. Here, we dissect the 2019/2020 influenza season not only with regard to its unusually early activity, but also with regard to the relative dynamics of type A and type B cases. We propose that the recent expansion of a novel influenza B/Victoria clade may be associated with this shift in the composition and kinetics of the influenza season in the United States. We use epidemiological transmission models to explore whether changes in the effective reproduction number or short-term cross-immunity between these viruses can explain the dynamics of influenza A and B seasonality. We find support for an increase in the effective reproduction number of influenza B, rather than support for cross-type immunity-driven dynamics. Our findings have clear implications for optimal vaccination strategies.

scholarly journals 2553. Individual Patient-Level Data Meta-Analysis of Live Attenuated and Inactivated Influenza Vaccine Effectiveness Among US Children, 2013–2014 Through 2015–2016

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S68-S68
Author(s):  
Jessie Chung ◽  
Brendan Flannery ◽  
Rodolfo Begue ◽  
Herve Caspard ◽  
Laurie Demarcus ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza A ◽  
The United States ◽  
Vaccine Effectiveness ◽  
Vaccination Status ◽  
Influenza B ◽  
Rt Pcr ◽  
Current Season ◽  
Influenza A H1n1 ◽  
Vaccine Type

Abstract Background Quadrivalent live attenuated influenza vaccine (LAIV4) was not recommended for use in the United States for the 2016–2017 and 2017–2018 influenza seasons based on US observational studies of vaccine effectiveness (VE) from 2013–2014 to 2015–2016. We pooled individual patient data on children aged 2–17 years enrolled in 5 US studies during these 3 influenza seasons to further investigate VE by vaccine type. Methods Analyses included 17,173 children enrolled in the US Department of Defense Global Laboratory-based Influenza Surveillance Program, US Influenza Vaccine Effectiveness Network, Influenza Incidence Surveillance Project, Influenza Clinical Investigation for Children, and a Louisiana State University study. Participants’ specimens were tested for influenza by reverse transcription-polymerase chain reaction (RT-PCR), culture, or a combination of rapid antigen testing and RT-PCR. VE was calculated by comparing odds of vaccination with either inactivated influenza vaccine (IIV) or LAIV4 among influenza-positive cases to test-negative controls and calculated as 100 × (1 − odds ratio) in logistic regression models with age, calendar time, influenza season, and study site (random effect). Patients were stratified by prior season vaccination status in a subanalysis. Results Overall, 38% of patients (N = 6,558) were vaccinated in the current season, of whom 30% (N = 1,979) received LAIV4. Pooled VE of IIV against any influenza virus was 51% (95% CI: 47, 54) versus 26% (95% CI: 15, 36) for LAIV4. Point estimates for pooled VE against any influenza by age group ranged from 45% to 58% for IIV and 19% to 34% for LAIV4 during the 3 seasons (Figures 1 and 2). Pooled VE against influenza A(H1N1)pdm09 was 67% (95% CI: 62, 72) for IIV versus 20% (95% CI: −6, 39) for LAIV4. Pooled VE against influenza A(H3N2) was 29% (95% CI: 14, 42) for IIV versus 7% (95% CI: −11, 23) for LAIV4, and VE against influenza B was 52% (95% CI: 42, 60) for IIV and 66% (95% CI: 47, 77) for LAIV4. VE against influenza A(H1N1)pdm09 was lower for LAIV4 versus IIV across all strata of prior season vaccination (Figure 3). Conclusion Consistent with individual studies, our pooled analyses found that LAIV4 effectiveness was reduced for all age groups against influenza A(H1N1)pdm09 compared with IIV. This result did not vary based on prior vaccination status. Disclosures H. Caspard, AstraZeneca: Employee, Salary.

scholarly journals Early season estimate of influenza vaccination effectiveness against influenza hospitalisation in children, Hong Kong, winter influenza season 2018/19

2019 ◽  
Vol 24 (5) ◽  
Author(s):  
Susan S Chiu ◽  
Mike YW Kwan ◽  
Shuo Feng ◽  
Eunice LY Chan ◽  
Huiying Chua ◽  
...  
Keyword(s):  
Hong Kong ◽  
Confidence Interval ◽  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Influenza A ◽  
Influenza Season ◽  
Public Hospitals ◽  
Early Season ◽  
Influenza A H1n1

The winter 2018/19 influenza season in Hong Kong has been predominated by influenza A(H1N1)pdm09 as at January 2019. We enrolled 2,016 children in three public hospitals in Hong Kong between 2 September 2018 and 11 January 2019. Using the test-negative approach, we estimated high early season effectiveness of inactivated influenza vaccine against influenza A or B of 90% (95% confidence interval (CI): 80–95%) and 92% (95% CI: 82–96%) against influenza A(H1N1)pdm09.

scholarly journals Trivalent inactivated influenza vaccine effective against influenza A(H3N2) variant viruses in children during the 2014/15 season, Japan

2016 ◽  
Vol 21 (42) ◽  
Author(s):  
Norio Sugaya ◽  
Masayoshi Shinjoh ◽  
Chiharu Kawakami ◽  
Yoshio Yamaguchi ◽  
Makoto Yoshida ◽  
...  
Keyword(s):  
New York ◽  
Influenza Vaccine ◽  
Influenza A ◽  
Influenza Season ◽  
Influenza Virus Infection ◽  
Case Control ◽  
H3n2 Virus ◽  
Influenza B ◽  
Influenza A Viruses ◽  
Negative Case

The 2014/15 influenza season in Japan was characterised by predominant influenza A(H3N2) activity; 99% of influenza A viruses detected were A(H3N2). Subclade 3C.2a viruses were the major epidemic A(H3N2) viruses, and were genetically distinct from A/New York/39/2012(H3N2) of 2014/15 vaccine strain in Japan, which was classified as clade 3C.1. We assessed vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children aged 6 months to 15 years by test-negative case–control design based on influenza rapid diagnostic test. Between November 2014 and March 2015, a total of 3,752 children were enrolled: 1,633 tested positive for influenza A and 42 for influenza B, and 2,077 tested negative. Adjusted VE was 38% (95% confidence intervals (CI): 28 to 46) against influenza virus infection overall, 37% (95% CI: 27 to 45) against influenza A, and 47% (95% CI: -2 to 73) against influenza B. However, IIV was not statistically significantly effective against influenza A in infants aged 6 to 11 months or adolescents aged 13 to 15 years. VE in preventing hospitalisation for influenza A infection was 55% (95% CI: 42 to 64). Trivalent IIV that included A/New York/39/2012(H3N2) was effective against drifted influenza A(H3N2) virus, although vaccine mismatch resulted in low VE.

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