Results
All items received a favorable expert judgment evaluation (V-Aiken > 0.75), and an acceptable internal confidence level was obtained with an alpha of 0.86.

A total of 934 persons completed the survey. We excluded 10 respondents, including two duplicates, 5 minors and 3 due to informed consent (refusal to participate or having less than two doses). This resulted in an analyzed sample of 924 people, with 91.7% responding through virtual questionnaires and 8.3% through physical surveys. No significant differences were observed between the groups concerning the intention to be vaccinated ( p = 0.759), so both subpopulations were merged into one. Of the participants, 53.7% ( n = 496) were female, 66.5% ( n = 614) were aged between 18 and 29 years, 87.1% ( n = 805) lived in an urban area and 62.0% ( n = 573) lived in the Coastal region. Additionally, 42.8% ( n = 395) reported being food insecure, while 29.9% ( n = 276) had economic insecurity; participants who reported having children was 31.8% ( n = 294) ( Table 1A ). In addition, 26.0% ( n = 240) presented depressive symptoms and 23.2% ( n = 214) reported having comorbidities. The probability of acceptance of vaccination with the booster dose was 66.6% ( n = 615) on the recommendation of physicians, 54.0% ( n = 499) on the recommendation of government health authorities (MINSA), 43.6% ( n = 384) on the recommendation of family and friends, and 17.2% ( n = 159) on the recommendation of politicians. In addition, 71.7% ( n = 662) reported some mild-moderate ESAVI, 10.8% reported symptomatology suspicious for COVID-19 and 86.3% ( n = 797) of the participants had three doses of vaccine at the time of the survey. Likewise, 88.1% ( n = 814) affirmed IBV ( Table 1B ). The IBV with the booster dose varied by department, with the following percentages: Junín (93.8%), Amazonas (91.8%), Lima (90.5%), Lambayeque (87.9%), San Martín (87.9%), Cajamarca (85.0%) and Piura (83.2%).

Notes:

While, the data from non-responders cannot be quantified, an interim analysis of the physical survey non-responders indicated a percentage of less than 10%. The comparison between the population that participated in the physical and virtual surveys did not differ (see Table S1 ).

Several variables were found to be significantly associated with the intention to be vaccinated (IBV), as detailed in Table 2 . These variables include age ( p = 0.002), having children ( p = 0.002), being related to the health sector ( p = 0.001), perception of the efficacy and protective effect of the booster dose (<0.001), as well as fear of adverse effects ( p < 0.001) were significantly associated with the IBV ( Table 2 ). Additionally, bivariate analysis revealed a significantly association ( p < 0.001) between IBV and the recommendation of physicians, government health authorities (MINSA), family and friends, and politicians ( Table 2 ).

Notes:

In the simple regression, being related to health (PR = 1.10; 95% CI [1.04–1.16]; p < 0.001), having a good perception of its efficacy and protective effect (PR = 3.69; 95% CI [2.57–5.30]; p < 0.001), the recommendation of family and friends (PR = 1.28; 95% CI [1.22–1.34]; p < 0.001), physicians (PR = 1.52; 95% CI [1.38–1.66]; p < 0.001), government health authorities (MINSA) (PR = 1.32; 95% CI [1.24–1.40]; p < 0.001) and politicians (PR = 1.17; 95% CI [1.13–1.21]; p < 0.001) were associated with a higher IBV. Conversely, being aged 45 or older (PR = 0.89; 95% CI [0.81–0.97]; p = 0.011), having children (PR = 0.92; 95% CI [0.87–0.98]; p = 0.006) and being afraid of adverse effects (PR = 0.91; 95% CI [0.87–0.96]; p < 0.001), were associated with a lower prevalence of IBV with the booster dose. In the adjusted regression, being male (aPR = 1.05; 95% CI [1.01–1.10]; p = 0.024), recommendation by family and friends (aPR = 1.08; 95% CI [1.04–1.12]; p < 0.001), and recommendation by physicians (aPR = 1.40; 95% CI [1.27–1.55]; p < 0.001) were associated with a higher prevalence of IBV with the booster dose, while age 45 years and older was associated with lower IBV (aPR = 0.89; 95% CI [0.81–0.98]; p = 0.018) ( Table 3 ).

Notes:

95% CI 95% confidence interval cPR crude prevalence ratio aPR adjusted prevalence ratio NA not supported in the multiple regression model

95% confidence interval

crude prevalence ratio

adjusted prevalence ratio

not supported in the multiple regression model