Determinants of seasonal influenza and COVID-19 vaccine uptake in high-risk individuals in northern Sweden

Determinants of seasonal influenza and COVID-19 vaccine uptake in high-risk individuals in northern Sweden

Targeted communication, such as risk-stacking to improve risk-awareness, harmonized eligibility criteria, and co-administration, may help overcome remaining vaccination barriers in high-risk individuals.

Determinants of influenza vaccination in a French primary care population in the post-COVID-19 era.

BACKGROUND Influenza vaccination coverage in France remains suboptimal, with variability across population groups. We assessed demographic and behavioral determinants of influenza vaccination in the post-COVID-19 period among a primary care population in the Haute-Vienne department (Nouvelle-Aquitaine, France). METHODS We conducted a cross-sectional survey using an anonymous, self-administered questionnaire distributed to adults attending five general-practice sites between May and July 2023. The primary outcome was receipt of the 2022-2023 influenza vaccine. Candidate determinants included age, sex, municipality size, socio-professional category, eligibility criteria (age ≥ 65 years, healthcare-worker status, chronic conditions, or pregnancy), prior influenza vaccination, number of COVID-19 vaccine doses received, and self-reported history of influenza infection. Associations were examined using chi-square tests, Cochran-Armitage trend tests, and univariate logistic regression. Two multivariable logistic regression models were then constructed: a demographic model including age, sex, municipality size, socio-professional category, and the presence of any comorbidity or pregnancy, and a behavioral model including prior influenza vaccination and COVID-19 vaccination status (≥ 3 doses vs. ≤ 2 doses). Adjusted results were expressed as adjusted odds ratios (aOR) with 95% confidence intervals (95% CI). RESULTS Among the 800 questionnaires distributed, 432 were returned (participation rate: 54%). Overall, 75.9% of participants met at least one eligibility criterion for influenza vaccination. Influenza vaccination coverage for the 2022-2023 season was 58.3% and differed by municipality size (38.8% in areas with fewer than 5,000 inhabitants; 59.2% in those with 5,000-10,000; and 64.3% in those with more than 10,000, p = 0.0003) and increased with the regularity of prior influenza vaccination (6.7% among never vaccinated, 55.9% among occasional, and 96.6% among annually vaccinated, p < 0.0001). Coverage was also associated with the number of COVID-19 vaccine doses received (p < 0.0001). In the demographic model, age ≥ 65 years was associated with higher vaccination uptake (aOR 8.55, 95% CI 1.88-61.73, p = 0.012), whereas other demographic variables were not independently associated with vaccination uptake. In the behavioral model, prior influenza vaccination was strongly associated with vaccination uptake (aOR 16.20, 95% CI 7.21-36.41 for occasional vs. never and aOR 331.21, 95% CI 122.57-894.99 for annual vs. never; both p < 0.001). Receipt of ≥ 3 COVID-19 vaccine doses was also independently associated with vaccination uptake (aOR 2.64, 95% CI 1.01-6.89, p = 0.047). CONCLUSIONS In this primary care survey, influenza vaccination during the 2022-2023 season was primarily associated with prior influenza vaccination history, suggesting persistence of vaccination practices over time. Age ≥ 65 years and receipt of ≥ 3 COVID-19 vaccine doses were also independently associated with vaccination uptake, although to a lesser extent. Targeted strategies that reinforce continuity (annual reminders, vaccination offers during routine visits, and co-administration options) and encourage initiation among previously unvaccinated adults could help improve coverage. TRIAL REGISTRATION Not applicable.

Factors associated with vaccination against Seasonal Influenza and SARS-CoV-2 in the UK among FluSurvey participants, 2023-2025.

Seasonal Influenza and COVID-19 vaccination programmes are critical for reducing morbidity and mortality in older adults, yet uptake remains uneven across populations. We aimed to profile vaccination attitudes and examine predictors of COVID-19/influenza vaccination uptake among a UK participatory surveillance system - FluSurvey. We analysed FluSurvey data from participants aged [≥]65 years who were eligible for both vaccines in the 2023-2024 and 2024-2025 Autumn - Winter seasonal campaigns. Descriptive analyses examined self-reported attitudes to influenza vaccination. Logistic regression examined factors (age, sex, socioeconomic status, education, employment, transport, smoking and chronic conditions) associated with influenza and COVID-19 vaccination uptake in each season, adjusting for confounders. Belonging to a risk group and reducing risk of influenza were frequently reported motivations for influenza vaccination, while building natural immunity and concerns around safety and adverse effects were frequently reported barriers. Individuals vaccinated against COVID-19 were more likely to receive an influenza vaccination (aOR2023-2024=13.90 [9.28-21.17]; aOR2024-2025=8.54 [5.82-12.60]), and vice-versa (aOR2023-2024=13.91 [9.30-21.19]; aOR2024-2025=8.52 [5.81-12.58]). Lower educational attainment was associated with lower odds of COVID-19 vaccination (aOR2023-2024=0.59 [0.45-0.78], aOR2024-2025: 0.56 [0.39-0.79]). Other results were weaker or demonstrated variation by season. Our findings highlight recent attitudes and barriers to influenza and COVID-19 vaccination among the FluSurvey cohort, which may inform approaches to improve vaccination coverage in the population.

Uptake of Influenza, Pneumococcal, and COVID-19 Vaccines Among People Living with HIV: Findings from the Ontario HIV Treatment Network Cohort Study.

COVID-19 vaccination timing, relative to acute COVID-19, and subsequent risk of long COVID

Summary Background Vaccination is a vital tool in preventing acute COVID-19 and may confer additional protection against Long COVID, although it is unclear whether this protection wanes over time. Methods We assessed electronic health record (EHR) data from a national, retrospective cohort of patients, comparing the 12-month cumulative incidence of Long COVID (ICD-10 code U09.9) among (A) patients who were vaccinated versus unvaccinated (two or more versus zero doses) and (B) patients diagnosed with acute COVID-19 1–3 months, 3–5 months, or 5–7 months after vaccination. Findings In our binary cohort (n = 519,980), we found that patients who were vaccinated had a lower risk of Long COVID (adjusted risk ratio 0.84 (0.81, 0.88)) or mortality (adjusted risk ratio 0.83 (0.81, 0.86)) than patients who were unvaccinated. In our longitudinal cohort (n = 1,085,291), we did not find significant heterogeneity in Long COVID risk during the seven months following vaccination. Interpretation We found that COVID-19 vaccination was protective against Long COVID, and we did not observe a significant waning of this protection within seven months after vaccination. Funding This research was financially supported by the 10.13039/100000060National Institute of Allergy and Infectious Diseases (1K01AI182501 to Zachary Butzin-Dozier) and a Global Development grant (OPP1165144) from the 10.13039/100000865Bill & Melinda Gates Foundation to the 10.13039/100005595University of California, Berkeley, CA, USA. Individual authors were supported by the following funding sources: 10.13039/100000025NIMHR01131542 (PI Rena C. Patel), Jerrod Anzalone is supported by the 10.13039/100000057National Institute of General Medical Sciences, U54 GM115458, which funds the Great Plains IDeA-CTR Network. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

Influenza Vaccination and Symptom Burden in Ambulatory Patients with Confirmed Influenza: Evidence from Case-ascertained Household Transmission Studies.

BACKGROUND The extent to which influenza vaccination may temper disease remains uncertain. We compared symptoms between influenza vaccinated and unvaccinated ambulatory persons with influenza. METHODS We conducted household transmission studies across multiple US sites during consecutive influenza seasons from 2017-2018 through 2022-2023 (excluding 2020-2021 season with minimal influenza activity). We collected daily symptom diaries and respiratory specimens. Three scores were calculated, varying weights on specific symptoms: 1) influenza-like illness (ILI); 2) lower respiratory; and 3) all symptoms. For each score, we examined the daily mean score between those vaccinated and unvaccinated against influenza using weighted multivariable linear mixed effects and frailty models. RESULTS Study included 869 children (41% vaccinated, 47% female, 58% white, non-Hispanic) and 653 adults (42% vaccinated, 65% female, 72% white, non-Hispanic) with laboratory-confirmed influenza. In multivariable analyses, the mean difference in the daily ILI score was -0.16 (95% CI: -0.32, -0.01) between vaccinated and unvaccinated children and -0.18 (95% CI: -0.34, -0.01) for the lower respiratory score. There was no significant difference among adults. Influenza vaccination was not associated with time to symptom alleviation among children. However, ILI symptom alleviation occurred earlier among vaccinated (HR: 1.30, 95% CI: 1.04, 1.62) adults. CONCLUSION Ambulatory children with influenza who were vaccinated experienced less ILI symptom burden compared to those who were not vaccinated against influenza, but vaccination was not associated with symptom duration. Conversely, among ambulatory adults with influenza, vaccination and symptom burden were not associated, but vaccination was associated with faster alleviation of ILI symptoms.