Copyright © 2021 by Author/s and Licensed by Modestum. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Electronic Journal of General Medicine 2021, 18(5), em303 e-ISSN: 2516-3507 https://www.ejgm.co.uk/ Original Article OPEN ACCESS Validation of a Scale to Measure the Perception of SARS-CoV-2 Vaccines Acceptance: The VAC-COVID-19 Scale Christian R. Mejia 1* , J. Franco Rodriguez-Alarcon 2,3 , Dayana Ticona 4 , Kevin Flores-Lovon 4 , Marco Paredes-Obando 5 , Maryory S. Avalos-Reyes 6 , Laura Ccasa-Valero 7 , Macarena Carbajal 8 , Renzo Felipe Carranza Esteban 9 , Oscar Mamani-Benito 10 , Oriana Rivera-Lozada 11 , Marcos Roberto Tovani-Palone 12** 1 Translational Medicine Investigation Centre, Universidad Norbert Wiener, Lima, PERU 2 Asociación Médica de Investigación y Servicios en Salud, Lima, PERU 3 Facultad de Medicina Humana “Manuel Huaman Guerrero”, Universidad Ricardo Palma, Lima, PERU 4 Universidad Nacional de San Agustín de Arequipa, Arequipa, PERU 5 Universidad Nacional de la Amazonia Peruana, Loreto, PERU 6 Universidad Privada Antenor Orrego, La Libertad, PERU 7 Universidad Nacional del Altiplano, Puno, PERU 8 Universidad Nacional Hermilio Valdizan, Huánuco, PERU 9 Escuela Profesional de Psicología, Universidad San Ignacio de Loyola, Lima, PERU 10 Universidad Peruana Unión, Juliaca, PERU 11 South American Centre for Education and Research in Public Health, Universidad Norbert Wiener, Lima, PERU 12 Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, BRAZIL *Corresponding Author: christian.mejia.md@gmail.com **Corresponding Author: marcos_palone@hotmail.com Citation: Mejia CR, Rodriguez-Alarcon JF, Ticona D, Flores-Lovon K, Paredes-Obando M, Avalos-Reyes MS, Ccasa-Valero L, Carbajal M, Carranza Esteban RF, Mamani-Benito O, Rivera-Lozada O, Tovani-Palone MR. Validation of a Scale to Measure the Perception of SARS-CoV-2 Vaccines Acceptance: The VAC-COVID-19 Scale. Electron J Gen Med. 2021;18(5):em303. https://doi.org/10.29333/ejgm/11012 ARTICLE INFO ABSTRACT Received: 22 Jan. 2021 Accepted: 20 Mar. 2021 Introduction: Since the announcement of the start of SARS-CoV-2 vaccines development, many myths and vaccine opponents have come to the fore. Therefore, in this scenario, it is imperative to have an instrument to assess the population perception of this subject matter. Objective: To validate a scale to measure the perception of SARS-CoV-2 vaccines acceptance. Methods: This is an instrumental and multicentre study, through which a list of possible reasons for whether or not people would be vaccinated was generated. After submitting them to 15 experts, a pilot survey was conducted virtually in a population of almost 3000 participants in the 24 regions of Peru. Descriptive statistics and the exploratory factor analysis (EFA) were conducted using the FACTOR program. Results: The Kaiser-Meyer-Olkin (KMO) coefficient (KMO = 0.917) and the Bartlett’s test of sphericity (3343.3; gl = 136; p < 0.001) were conducted. According to EFA results, two factors were found to explain 58.17% of the total variance. The fit indices show that the proposed model is adequate (χ 2 = 826.321; df = 43; p = 0.001; RMR = 0.054; GFI = 0.952; AGFI = 0.927; CFI = 0.946; TLI = 0.931; and RMSEA = 0.078). Finally, Cronbach’s α was found to be very satisfactory for the generated scale (α = 0.831; 95% CI = 0.82 – 0.84). Conclusion: A simple and efficient scale was validated to assess positive and negative perceptions of SARS-CoV-2 vaccines (the VAC-COVID-19 scale), with a Cronbach’s coefficient of 0.831. Keywords: perception, mass vaccination, COVID-19 vaccines, SARS-CoV-2, validation, Peru INTRODUCTION The coronavirus disease 2019 (COVID-19) pandemic has created a global public health emergency due to its rapid spread and significant morbidity and mortality. Several segments of the society have been affected, and so far the number of confirmed cases of the disease worldwide has already exceeded 90 million [1]. As a result, many pharmaceutical companies and countries set out to develop a vaccine to help put an end to the pandemic. Thus, some viable vaccines for mass vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were developed in a very short time. Although the vaccination is urgent and the health systems of several countries can collapse at any time, its implementation and subsequent immunization are suffering some setbacks [2]. Moreover, there is the precedent that in situations such as this, the health sector often fails to carry out the vaccination process appropriately [3]. Another possible challenge in this context is the vaccine hesitation. Numerous studies conducted of Europe and North America on the population perception of vaccination have reported that greater acceptance of vaccines depends mainly on their safety and efficacy in clinical studies [4]. In addition, length of time of immunity, adverse effects, and the origin of the vaccine has been identified as the main factors associated