Impact of influenza vaccination programmes among the elderly population on primary care, Portugal, Spain and the Netherlands: 2015/16 to 2017/18 influenza seasons

Ausenda Machado*, Clara Mazagatos, Frederika Dijkstra, Irina Kislaya, Alin Gherasim, Scott A. McDonald, Esther Kissling, Marta Valenciano, Adam Meijer, Mariëtte Hooiveld, Baltazar Nunes, Amparo Larraur

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)
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Abstract

Background: To increase the acceptability of influenza vaccine, it is important to quantify the overall benefits of the vaccination programme. Aim: To assess the impact of influenza vaccination in Portugal, Spain and the Netherlands, we estimated the number of medically attended influenza-confirmed cases (MAICC) in primary care averted in the seasons 2015/16 to 2017/18 among those ≥65 years. Methods: We used an ecological approach to estimate vaccination impact. We compared the number of observed MAICC (n) to the estimated number that would have occurred without the vaccination programme (N). To estimate N, we used: (i) MAICC estimated from influenza surveillance systems, (ii) vaccine coverage, (iii) pooled (sub)type-specific influenza vaccine effectiveness estimates for seasons 2015/16 to 2017/18, weighted by the proportion of virus circulation in each season and country. We estimated the number of MAICC averted (NAE) and the prevented fraction (PF) by the vaccination programme. Results: The annual average of NAE in the population ≥65 years was 33, 58 and 204 MAICC per 100,000 in Portugal, Spain and the Netherlands, respectively. On average, influenza vaccination prevented 10.7%, 10.9% and 14.2% of potential influenza MAICC each season in these countries. The lowest PF was in 2016/17 (4.9–6.1%) with an NAE ranging from 24 to 69 per 100,000. Conclusions: Our results suggest that influenza vaccination programmes reduced a substantial number of MAICC. Together with studies on hospitalisations and deaths averted by influenza vaccination programmes, this will contribute to the evaluation of the impact of vaccination strategies and strengthen public health communication.
Original languageEnglish
Article number1900268
JournalEurosurveillance
Volume24
Issue number45
DOIs
Publication statusPublished - 7 Nov 2019
Externally publishedYes

ASJC Scopus subject areas

  • Epidemiology
  • Public Health, Environmental and Occupational Health
  • Virology

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