Low Influenza Vaccine Effectiveness Against A(H3N2)-Associated Hospitalizations in 2016–2017 and 2017–2018 of the Hospitalized Adult Influenza Vaccine Effectiveness Network (HAIVEN)

Abstract

Introduction The 2016-2017 and 2017-2018 influenza seasons were notable for high number of hospitalizations for influenza A(H3N2) despite vaccine and circulating strain match. Methods We evaluated vaccine effectiveness (VE) against hospitalization in the test-negative HAIVEN study. Nasal-throat swabs were tested by RT-PCR for influenza and VE was determined based on odds of vaccination by generalized estimating equations. Vaccine-specific antibody was measured in a subset of enrollees. Results A total of 6,129 adults were enrolled from ten hospitals. Adjusted VE against A(H3N2) was 22.8% (95% C.I. 8.3%, 35.0%), pooled across both years and 49.4% (95% C.I. 34.3%, 61.1%) against B/Yamagata. In 2017-2018, the A(H3N2) VE point estimate for the cell-based vaccine was 43.0% (95% C.I. -36.3%, 76.1%; 56 vaccine recipients) compared to 24.0% (95% C.I. 3.9%, 39.9%) for egg based vaccines. Among 643 with serology data, hemagglutinin antibodies against the egg-based A(H3N2) vaccine strain were increased in influenza-negative individuals. Conclusions Low VE for the A/Hong Kong/4801/2014 vaccine virus in both A(H3N2) seasons emphasizes concerns for continued changes in H3N2 antigenic epitopes, including changes that may impact glycosylation and ultimately reduce VE.

Relative Effectiveness of Cell-Cultured versus Egg-Based Seasonal Influenza Vaccines in Preventing Influenza-Related Outcomes in Subjects 18 Years Old or Older: A Systematic Review and Meta-Analysis

“…We performed the bibliographic search between the 7 th and 12 th of January 2021 and retrieved 5,393 publications. We identified nine additional publications [48][49][50][51][52] in two recent influenza conferences (Options X 2019 and ESWI 2020) and the author's datasets [30,[53][54][55], adding to 5,402 retrieved publications. Two authors screened the titles and abstracts, and the four authors reviewed and agreed on the screening result.…”

“…Two authors screened the titles and abstracts, and the four authors reviewed and agreed on the screening result. We identified 18 publications [28,[30][31][32][48][49][50][51][52][53][54][55][56][57][58][59][60][61]for full-text review (Figure 1). We performed a new search on the 1 st of April 2021 and did not identify additional publications.…”

“…Among the 18 publications, we excluded four conference abstracts [30,48,49,51] with duplicated results published in three journal papers [53,58,61]. The remaining 14 publications [28,31,32,50,[52][53][54][55][56][57][58][59][60][61] reported 53 results (Figure1, Table S1). We checked compliance with reporting IRO in subjects ≥18 years.…”

“…We included in our qualitative review 12 publications [28,32,[52][53][54][55][56][57][58][59][60][61] that reported 26 results (Figure 1). We describe the main characteristics of the publications and the reported results in Table 1 and Table 2.…”

“…Seven publications reported 14 results in the 2017-2028 influenza season [28,32,[54][55][56][57][58], four publications reported ten results in the 2018-2019 season [52,53,59,61], and one publication reported two results in the 2019-2020 season [60]. Eight publications reported 15 retrospective-cohort results [32,53,[56][57][58][59][60][61], and four publications reported 11 test-negative results [28,52,54,55]. One publication reported three results in the 18 and over age-group [55].…”