Age-specific vaccination coverage estimates for influenza, human papillomavirus and measles containing vaccines from seven population-based healthcare databases from four EU countries – The ADVANCE project

Understanding Prognostic Factors for Human Papillomavirus Vaccination: A Rural Community Case-Control Study

HPV vaccination coverage rates can vary depending on several factors. The main objective of this study is to identify possible independent prognostic factors that have an impact on HPV vaccination in a rural community, specifically related to sexual and reproductive health. A case-control, retrospective, community-based study was carried out on women aged 15 to 40 in the primary health centers of Southern Catalonia's Terres de l'Ebre region, Spain, from 1 January 2020 to 31 December 2022. A random sample of 520 women with an average age of 29.3 (SD 7.8) years old was included in the study. Independent prognostic factors: age OR 0.680 (95% CI: 0.635-0.729, p < 0.001), immigrant origin OR 0.215 (95% CI: 0.109-0.422, p < 0.001), and HPV PCR OR 7.402 (95% CI: 2.504-21.880, p < 0.001). The variables that showed a barrier effect for HPV vaccination were age (OR 0.680, 95% CI 0.635-0.729, p < 0.001), and immigrant origin (OR 0.215, 95% CI 0.109-0.422, p < 0.001). The variable that showed a facilitating effect for HPV vaccination was HPV PCR (OR 7.402, 95% CI 2.504-21.880, p < 0.001).

Influenza Vaccine Effectiveness against Hospitalization, Season 2021/22: A Test-Negative Design Study in Barcelona

BACKGROUND

Vaccination is considered the most effective measure for preventing influenza and its complications. The influenza vaccine effectiveness (IVE) varies annually due to the evolution of influenza viruses and the update of vaccine composition. Assessing the IVE is crucial to facilitate decision making in public health policies.

AIM

to estimate the IVE against hospitalization and its determinants in the 2021/22 season in a Spanish tertiary hospital.

METHODS

We conducted a prospective observational test-negative design study within the Development of Robust and Innovative Vaccine Effectiveness (DRIVE) project. Hospitalized patients with severe acute respiratory infection (SARI) and an available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). Vaccine information was obtained from electronic clinical records shared by public healthcare providers. Information about potential confounders was obtained from hospital clinical registries. The IVE was calculated by subtracting the ratio of the odds of vaccination in cases and controls from one, as a percentage (IVE = (1 - odds ratio (OR)) × 100). Multivariate IVE estimates were calculated using logistic regression.

RESULTS

In total, 260 severe acute respiratory infections (SARI) were identified, of which 34 were positive for influenza, and all were subtype A(H3N2). Fifty-three percent were vaccinated. Adjusted IVE against hospitalization was 26.4% (95% CI -69% to 112%). IVE determinants could not be explored due to sample size limitations.

CONCLUSION

Our data revealed non-significant moderate vaccine effectiveness against hospitalization for the 2021/2022 season.

A comparison between online social media discussions and vaccination rates: A tale of four vaccines

The recent COVID-19 pandemic has brought the debate around vaccinations to the forefront of public discussion. In this discussion, various social media platforms have a key role. While this has long been recognized, the way by which the public assigns attention to such topics remains largely unknown. Furthermore, the question of whether there is a discrepancy between people's opinions as expressed online and their actual decision to vaccinate remains open. To shed light on this issue, in this paper we examine the dynamics of online debates among four prominent vaccines (i.e., COVID-19, Influenza, MMR, and HPV) through the lens of public attention as captured on Twitter in the United States from 2015 to 2021. We then compare this to actual vaccination rates from governmental reports, which we argue serve as a proxy for real-world vaccination behaviors. Our results demonstrate that since the outbreak of COVID-19, it has come to dominate the vaccination discussion, which has led to a redistribution of attention from the other three vaccination themes. The results also show an apparent discrepancy between the online debates and the actual vaccination rates. These findings are in line with existing theories, that of agenda-setting and zero-sum theory. Furthermore, our approach could be extended to assess the public's attention toward other health-related issues, and provide a basis for quantifying the effectiveness of health promotion policies.

Influenza Vaccination and Risk of Ischemic Stroke: A Population-Based Case-Control Study

BACKGROUND AND OBJECTIVES

To assess the relationship between influenza vaccination in the general population and risk of a first ischemic stroke (IS) during pre-epidemic, epidemic, and postepidemic periods.

METHODS

A nested case-control study was conducted in a Spanish primary care database over 2001-2015. Individuals aged 40-99 years with at least 1 year registry and no history of stroke or cancer were selected to conform the source cohort, from which incident IS cases were identified and classified as cardioembolic or noncardioembolic. Five controls per case were randomly selected, individually matched with cases for exact age, sex, and date of stroke diagnosis (index date). A patient was considered vaccinated when he/she had a recorded influenza vaccination at least 14 days before the index date within the same season. Adjusted odds ratios (aORs) and their respective 95% CIs were computed through a conditional logistic regression. Pneumococcal vaccination was used as a negative control.

RESULTS

From a cohort of 3,757,621 patients, we selected 14,322 incident IS cases (9,542 noncardioembolic and 4,780 cardioembolic) and 71,610 matched controls. Of them, 41.4% and 40.5%, respectively, were vaccinated yielding a crude OR of 1.05 (95% CI 1.01-1.10). Vaccinated patients presented a higher prevalence of vascular risk factors, diseases, and comedication than those nonvaccinated, and after full adjustment, the association of influenza vaccination with IS yielded an aOR of 0.88 (95% CI 0.84-0.92), appearing early (aOR15-30 days 0.79; 95% CI 0.69-0.92) and slightly declining over time (aOR>150 days 0.92; 95% CI 0.87-0.98). A reduced risk of similar magnitude was observed with both types of IS, in the 3 epidemic periods, and in all subgroups analyzed (men, women, individuals younger and older than 65 years of age, and those with intermediate and high vascular risk). By contrast, pneumococcal vaccination was not associated with a reduced risk of IS (aOR 1.08; 95% CI 1.04-1.13).

DISCUSSION

Results are compatible with a moderate protective effect of influenza vaccine on IS appearing early after vaccination. The finding that a reduced risk was also observed in pre-epidemic periods suggests that either the "protection" is not totally linked to prevention of influenza infection or it may be partly explained by unmeasured confounding factors.

Prevalence of cervicovaginal human papillomavirus infection and genotypes in the pre-vaccine era in China: A nationwide population-based study

OBJECTIVE

The HPV vaccine has been licensed in mainland China since 2017. This study aimed to assess the epidemiological characteristics of HPV genotypes in the pre-vaccine era in China.

METHODS

We conducted a multicentric population-based study nested in the largest health clinic chain in China. Between January 1, 2017 and December 31, 2017, 427,401women aged 20 years or older with polymerase chain reaction-based HPV genotyping tests were included in the study. The cervicovaginal infection of 14 high-risk HPV genotypes and 9 low-risk genotypes was assessed using adjusted prevalence, multivariable logistic regression, cluster analysis, and heatmap.

RESULTS

HPV prevalence was 15.0% (95% confidence interval [CI]: 14.1-15.9%) in China, with high- and low-risk genotypes being 12.1% (95%CI: 11.4-12.7%) and 5.2% (95%CI: 4.8-5.7%), respectively. The prevalence of HPV genotypes corresponding to bivalent, quadrivalent, and nonavalent vaccines were 2.1%, 2.4%, and 8.3%, respectively, whereas the prevalence of non-vaccine high-risk genotypes was 5.7%. The most common high-risk genotypes were HPV-52 (3.5%), HPV-58 (2.1%), and HPV-16 (1.6%), and the prevalence of HPV-18 (0.6%), HPV-6 (0.1%), and HPV-11 (0.2%) were relatively low. Infection with HPV genotypes differed significantly across age groups and geographic locations.

CONCLUSION

HPV prevalence was high in the pre-vaccine era in China, and a population-based HPV vaccination strategy is needed in the future.

Utilization of influenza vaccination among chronically ill individuals in Germany: A nationwide claims-based analysis

BACKGROUND

Individuals with chronic diseases have a higher risk of serious complications or even death in case of influenza infection. The European Union (EU) set a goal to reach a vaccination coverage of 75% in seniors and chronically ill individuals. The aim of this study was to assess influenza vaccination uptake among individuals with a wide spectrum of chronic diseases and examine its regional variations and temporal trends over a period of the last ten years.

METHODS

We used nationwide SHI-physician outpatient claims data from the years 2009 to 2018 covering 87% of the total German population to assess influenza vaccination uptake among individuals over 1 year of age with at least one of the following chronic diseases: pulmonary, cardiovascular, liver, kidney, metabolic, neurological and musculoskeletal diseases, as well as immune deficiency disorders, including HIV infection.

RESULTS

Influenza vaccination coverage varied across patient populations between 19% (multiple sclerosis) and 44% (chronic kidney disease) in the influenza season 2017/18. Vaccination coverage was slightly higher among females than males, except for HIV/AIDS patients. Among HIV-patients vaccination coverage was higher by 7 percent points among males (43%) than females (37%). The coverage was higher nearly for all patient groups in the eastern than western federal states. Over the observation period vaccination uptake showed decreasing trends in most of the target groups. Among patients with HIV/AIDS and immune deficiency disorders a stagnating trend was observed.

CONCLUSIONS

Vaccination uptake among chronically ill individuals is suboptimal and far from the EU-defined target of 75%. There were substantial variations in coverage by disease groups, individual factors and regions. The disease-specific evaluation of the current study allows identification of populations at higher risk with considerable vaccination gaps. Further efforts are needed to improve vaccination uptake in these vulnerable population groups.

Trends, Coverage and Influencing Determinants of Influenza Vaccination in the Elderly: A Population-Based National Survey in Spain (2006-2017)

Influenza is a significant public health problem and the elderly are at a greater risk of contracting the disease. The vaccination coverage of the elderly is below the Spanish target of 65% for each influenza season. The aims of this study were to report the coverage of influenza vaccination in Spain among the population aged ≥65 years and high-risk groups for suffering chronic diseases, to analyze the time trends from 2006 to 2017 and to identify the factors which affect vaccination coverage. A nationwide cross-sectional study was conducted including 20,753 non-institutionalized individuals aged ≥65 years who had participated in the Spanish National Health Surveys in 2006, 2011/2012, and 2017. Sociodemographic, health-related variables, and influenza vaccination data were used. A logistic regression analysis was performed to determine the variables associated with influenza vaccination. Influenza vaccination coverage was 60%. By chronic condition, older people with high cholesterol levels and cancer had the lowest vaccination coverage (62.41% and 60.73%, respectively). This coverage declined from 2006 to 2017 in both groups. Higher influenza vaccination was associated with males, Spanish nationality, normal social support perceived, polypharmacy, worse perceived health, participation in other preventive measures, and increasing age and the number of chronic diseases.