The Vacinómetro® initiative: an eleven-year monitorization of influenza vaccination coverage rates among risk groups in Portugal

Annual vaccination is fundamental for individual and group protection against seasonal influenza infection. International and Portuguese healthcare organizations have established influenza vaccination coverage rate (VCR) targets for risk groups, namely 75% in people ≥ 65 years old. The Vacinómetro® initiative has been monitoring influenza VCR among target risk groups in Portugal since 2009,: Group 1, ≥ 65 years old; Group 2, patients with chronic conditions; Group 3, healthcare workers in direct contact with patients; and Group 4, 60-64 years old. Besides VCR, social-demographic and health-related variables have been evaluated. During the study period (2009/2010 - 2019/2020), the VCR increased in the 4 target risk groups: from 58.6% to 76.0% in Group 1 (reaching the WHO target); 33.3% to 72.0% in Group 2; 25.0% to 58.9% in Group 3; and 36.6% to 42.8% in Group 4. "Physician recommendation" was the main driver for vaccination whereas "lack of habit" was the main barrier to vaccination. Vacinómetro® data demonstrate that free-of-charge vaccination has a positive impact on VCR. The observed positive trends in influenza VCR demonstrate that public health measures implemented in Portugal to facilitate access to influenza vaccine result in increased vaccine uptake. Strategies to promote population literacy and the physician's awareness should be continued and reinforced. Free-of-charge vaccination criteria extended to more risk groups would also contribute to higher influenza VCR in Portugal.