Observational study of vaccination in cancer patients: How can vaccine coverage be improved?

Streptococcus pneumoniae and influenza vaccination rates in oncological patients - data from Germany

OBJECTIVES

Due to disease- or therapy-associated immunosuppression, oncological patients suffer from significantly higher morbidity and mortality due to infections transmitted by respiratory pathogens such as Streptococcus pneumoniae and influenza virus. Although the German Standing Committee on Vaccination (STIKO) provides specific recommendations for vaccination against these pathogens, there is no data on vaccination rates in this high-risk population.

METHODS

Data from the interventional EVO study were analyzed to provide information on vaccination rates against Streptococcus pneumoniae and influenza virus in oncological patients. Numbers presented in this publication summarize baseline and follow-up data of the control group; thus, data were not influenced by the intervention.

RESULTS

Data of 370 patients were analyzed; 20.5% of patients were treated for hematological malignancies and 79.5% for solid cancer. 28.1% of patients had received vaccination against influenza and 32.2% against Streptococcus pneumoniae; for the latter only 7.3% according recommendations. While vaccination rates where even lower for patients with thoracic carcinoma (influenza 26.7% and Streptococcus pneumoniae 6.0% according to STIKO recommendations), rates in patients with multiple myeloma were remarkably higher (39.0% and 14.6%).

CONCLUSIONS

Despite strong recommendations to vaccinate and the clear clinical need to prevent infections in the vulnerable group of oncological patients, only the minority was vaccinated against Streptococcus pneumoniae or influenza, underlining the urgent need for better vaccination strategies in this high-risk population.

Changes in vaccination uptake against pneumococcal disease, influenza, and coronavirus disease 2019 (COVID-19) before and after a Head and Neck cancer diagnosis

BACKGROUND

Pneumonia is one of the main contributors to non-cancer mortality among patients with head and neck cancer (HNC). This study aimed to determine the vaccine uptake for pneumococcal polysaccharide and conjugate vaccines, quadrivalent influenza vaccines, and mRNA COVID-19 vaccines before and after an HNC diagnosis. Furthermore, the study investigated the timing of vaccination after a cancer diagnosis.

MATERIALS & METHODS

This register based multicentre study included Danish patients ≥ 18y diagnosed with HNC between 2018 and 2021. The vaccine uptake was assessed by calculating cumulative incidence (CI), while the timing of vaccination after an HNC diagnosis was explored by calculating incidence rates of vaccination the first and second half year after a cancer diagnosis.

RESULTS

The cumulative incidence of vaccine uptake for pneumococcal vaccines was estimated to be 8 % and 16 % one year before and after an HNC diagnosis, respectively. The CIs were 36 % and 38 % for quadrivalent influenza vaccines, respectively, whereas the CIs of vaccine uptake for mRNA COVID-19 vaccines were 60 % and 89 %. The IR of mRNA COVID-19 vaccinations the first half year after HNC diagnosis were 273 per 1000 person-months of follow-up (PMFU) and 111 per 1000 PMFU the second half year, respectively (IRR: 0.38, p < 0.001). Comparing the same periods, the IR of quadrivalent influenza vaccination was 28 per 1000 PMFU and 51 per 1000 PMFU (IRR: 1.95, 0 < 0.001). The IRs of pneumococcal vaccinations were 11 per 1000 PMFU and 14 per 1000 PMFU (IRR 1.28, p = 0.21).

CONCLUSIONS

Although our study shows a significant increase in pneumococcal and COVID-19 vaccine uptake after HNC diagnosis, a gap remains in vaccine uptake before diagnosis, underscoring the need for increased awareness of vaccination options and recommendations. Our findings could serve as a reference for future recommendations.

Effectiveness of COVID-19 vaccines against severe outcomes in cancer patients: Real-world evidence from self-controlled risk interval and retrospective cohort studies

BACKGROUND

The effectiveness of COVID-19 vaccines is generally reduced in cancer patients compared to the general population. However, there are only a few studies that compare the relative risk of breakthrough infections and severe COVID-19 outcomes in fully vaccinated cancer patients versus their unvaccinated counterparts.

METHODS

To assess the effectiveness of COVID-19 vaccines in cancer patients, we employed (1) a self-controlled risk interval (SCRI) design, and (2) a retrospective matched cohort design. A SCRI design was used to compare the risk of breakthrough infection in vaccinated cancer patients during the period immediately following vaccination ("control window") and the period in which immunity is achieved ("exposure windows"). The retrospective matched cohort design was used to compare the risk of severe COVID-19 outcomes between vaccinated and unvaccinated cancer patients. For both studies, data were extracted from the Korea Disease Control and Prevention Agency-COVID-19-National Health Insurance Service cohort, including demographics, medical history, and vaccination records of all individuals confirmed with COVID-19. We used conditional Poisson regression to calculate the incidence rate ratio (IRR) for breakthrough infection and Cox regression to estimate the hazard ratio (HR) for severe outcomes.

RESULTS

Of 14,448 cancer patients diagnosed with COVID-19 between October 2020 and December 2021, a total of 217 and 3996 cancer patients were included in the SCRI and cohort study respectively. While the risk of breakthrough infections, measured by the incidence rate in the control and exposure windows, did not show statistically significant difference in vaccinated cancer patients (IRR=0.88, 95% CI: 0.64-1.22), the risk of severe COVID-19 outcomes was significantly lower in vaccinated cancer patients compared to those unvaccinated (HR=0.27, 95% CI: 0.22-0.34).

CONCLUSION

COVID-19 vaccines significantly reduce the risk of severe outcomes in cancer patients, though their efficacy against breakthrough infections is less evident.

Recent changes to adult national immunization programs for pneumococcal vaccination in Europe and how they impact coverage: A systematic review of published and grey literature

Despite widespread use of pneumococcal vaccines throughout Europe, the burden of pneumococcal disease (PD) in adults is considerable. To mitigate this burden, National Immunization Technical Advisory Groups (NITAGs) and Health Technology Assessment (HTA) agencies assess the value of different vaccine schedules for protecting against PD. The aim of this review was to assess the evidence and rationales used by NITAGs/HTA agencies, when considering recent changes to National Immunization Programs (NIPs) for adults, and how identified changes affected vaccine coverage rates (VCRs). A systematic review was conducted of published literature from PubMed® and Embase®, and gray literature from HTA/NITAG websites from the last 5 y, covering 31 European countries. Evidence related to NIP recommendations, epidemiology (invasive PD, pneumonia), health economic assessments and VCRs were collected and synthesized. Eighty-four records providing data for 26 countries were identified. Of these, eight described explicit changes to NIPs for adults in seven countries. Despite data gaps, some trends were observed; first, there appears to be a convergence of NIP recommendations in many countries toward sequential vaccination, with a pneumococcal conjugate vaccine (PCV), followed by pneumococcal polysaccharide vaccine 23. Second, reducing economic or healthcare burden were common rationales for implementing changes. Third, most health economic analyses assessing higher-valency PCVs for adults found its inclusion in NIPs cost-effective. Finally, higher coverage rates were seen in most cases where countries had expanded their NIPs to cover at-risk populations. The findings can encourage agencies to improve surveillance systems and work to reach the NIP's target populations more effectively.

Preventive health care in blood cancer survivors: results from the ABC study

BACKGROUND

Blood cancer survivors are at increased risk for second primary malignancies, cardiovascular diseases, and infections. Little is known about preventive care in blood cancer survivors.

METHODS

Our questionnaire-based study included blood cancer patients diagnosed at the University Hospital of Essen before 2010, with a ≥ 3-year interval from the last intense treatment. One section of the retrospective study covered preventive care (cancer screening, cardiovascular screening, vaccination).

RESULTS

Preventive care was delivered by a general practitioner for 1100 of 1504 responding survivors (73.1%), by an oncologist for 125 (8.3%), by a general practitioner together with an oncologist for 156 (10.4%), and by other disciplines for 123 (8.2%). Cancer screening was more consistently performed by general practitioners than by oncologists. The converse was true for vaccination, with particularly high vaccination rates in allogeneic transplant recipients. Cardiovascular screening did not differ between care providers. Cancer and cardiovascular screening rates in survivors eligible for statutory prevention programs were higher than in the general population (skin cancer screening 71.1%; fecal occult blood testing 70.4%; colonoscopy 64.6%; clinical breast examination 92.1%; mammography 86.8%; cervical smear 86.0%; digital rectal examination 61.9%; blood pressure test 69.4%; urine glucose test 54.4%; blood lipid test 76.7%; information about overweight 71.0%). The Streptococcus pneumoniae vaccination rate was higher (37.0%) and the influenza vaccination rate was lower (57.0%) than in the general population.

CONCLUSIONS

Utilization of preventive care is high among German blood cancer survivors. To ensure widespread delivery and avoid redundancy, communication between oncologists and preventive care providers is essential.

A Nationwide Digital Multidisciplinary Intervention Aimed at Promoting Pneumococcal Vaccination in Immunocompromised Patients

Immunocompromised patients (IPs) are at high risk for infections, some of which are vaccine-preventable. The Israeli Ministry of Health recommends pneumococcal conjugate vaccine 13 (PCV13) and pneumococcal polysaccharide vaccine 23 (PPSV23) for IP, but vaccine coverage is suboptimal. We assessed the project's effectiveness in improving the pneumococcal vaccination rate among IP. An automated population-based registry of IP was developed and validated at Maccabi Healthcare Services, an Israeli health maintenance organization serving over 2.6 million members. Included were transplant recipients, patients with asplenia, HIV or advanced kidney disease; or those receiving immunosuppressive therapy. A personalized electronic medical record alert was activated reminding clinicians to consider vaccination during IP encounters. Later, IP were invited to get vaccinated via their electronic patient health record. Pre- and post-intervention vaccination rates were compared. Between October 2019 and October 2021, overall PCV13 vaccination rates among 32,637 IP went up from 11.9% (n = 3882) to 52% (n = 16,955) (p < 0.0001). The PPSV23 vaccination rate went up from 39.4% (12,857) to 57.1% (18,652) (p < 0.0001). In conclusion, implementation of targeted automated patient- and clinician-facing alerts, a remarkable increase in pneumococcal vaccine uptake was observed among IP. The outlined approach may be applied to increase vaccination uptake in large health organizations.

Impact of pharmacist-led educational intervention on pneumococcal vaccination rates in cancer patients: a randomized controlled study

PURPOSE

This study aimed to evaluate clinical pharmacist's contribution to the pneumococcal vaccination rate by providing education to cancer patients in hospital settings.

METHODS

This study was conducted in 2 tertiary-care hospitals' medical oncology outpatient clinics. Patients over 18 years of age and diagnosed with cancer for less than 2 years, in remission stage, and have not previously received the pneumococcal vaccine were included. Patients were randomized to intervention and control groups. The intervention group was provided vaccination education and recommended to receive the PCV13 vaccine. The control group received routine care. Patients' knowledge about pneumonia/pneumococcal vaccine, Vaccine Attitude Examination Scale (VAX) score, and vaccination rates were evaluated at baseline and 3 months after the education.

RESULTS

A total of 235 patients (intervention: 117, control: 118) were included. The mean age ± SD was 57.86 ± 11.88 years in the control and 60.68 ± 11.18 years in the intervention groups. The numbers of correct answers about pneumonia/pneumococcal vaccine (p = 0.482) and VAX scores (p = 0.244) of the groups were similar at baseline. After the intervention, the median (IQR) number of correct answers in intervention group [10(3)] was higher than control group [8(4)] (p < 0.001). After the education, the total VAX score (mean ± SD) was less in intervention group (33.09 ± 7.018) than the control group (36.07 ± 6.548) (p = 0.007). Three months after the education, 20.2% of the patients in the intervention and 6.1% in the control groups were vaccinated with pneumococcal vaccine (p = 0.003).

CONCLUSIONS

The pneumococcal vaccination rate in cancer patients has increased significantly by the education provided by a clinical pharmacist in hospital settings.

Effect of medical staff training on vaccination coverage in outpatients with cancer: An interventional multicenter before-and-after study

Purpose

Despite widely disseminated guidelines, pneumococcal and influenza vaccination coverage (VC) remains insufficient in patients with cancer receiving cancer treatment. We performed an interventional study to evaluate VC in patients with cancer treated at the medical oncology departments of three North-of-France hospitals and to assess the effect of medical staff training on VC in these patients.

Methods

A standardized questionnaire assessed VC in adult patients with cancer receiving anticancer treatment at three day hospitals during December 2-7, 2019. Subsequently (January 2020), we organized educational training sessions for medical staff from each hospital to discuss the current vaccination guidelines. To assess the impact of training on pneumococcal and influenza VC, we re-administered the same questionnaire in March 2020. Because there are no specific guidelines on Diphtheria-Tetanus-Pertussis (DTP) vaccination and no improvement was expected, DTP VC acted as an internal control.

Results

In total, 272 patients from all three hospitals were enrolled in the "before study"; 156 patients from only two hospitals were enrolled in the "after study" as medical training and data collection at the third were impossible because of administrative reasons and COVID-19 pandemic. The predictors were age for DTP VC; treatment center for pneumococcal VC; and age, sex, and tumor histology (adenocarcinoma vs. others) for influenza VC. Neither influenza VC (42.6% vs. 55.1%, p = 0.08), nor pneumococcal VC were significantly improved post-intervention (11.8% vs. 15.4%, p = 1). There seems to be a small effect in the most fragile for influenza VC.

Conclusion

As expected, VC was very low in patients with cancer, consistent with the literature. There was no impact of the intervention for pneumococcal and influenza VC.

Controlled non-randomised before-after study evaluating the impact of a focused recommendation card on vaccination rates of oncological patients-The Easy Vaccination in Oncology (EVO) strategy

OBJECTIVE

By implementing a focused must-have vaccination strategy (Easy Vaccination in Oncology [EVO]), we aimed to increase rates for high-impact vaccinations (Streptococcus pneumoniae, influenza, herpes zoster and hepatitis B) in the at-risk population of oncological patients.

METHODS

In this German multicentre interventional non-randomised controlled two-arm open trial with repeated cross-sectional data collection, we evaluated the EVO strategy as an easy to implement approach. Vaccination rates were assessed in the outpatient setting and re-assessed after 3 months. A generalised linear mixed model (GLMM) was used to assess the primary endpoint (Streptococcus pneumoniae vaccination rates according to recommendations), taking clustering within clinics into account.

RESULTS

Vaccination rates substantially increased in the intervention group; Streptococcus pneumoniae +21.5% (+16.7% according to recommendations), influenza +12.2%, herpes zoster +13.3% (+13.6% age group 50+), and hepatitis B +11%. Vaccination rates in the control group tended to decrease or increase only moderately (-5.8% [-3.8%], +7.4%, +2.1% [1.4%], and -1.7%, respectively). GLMM showed significant effect of the intervention (OR 7.50, 95% CI 2.18-25.80, p = 0.001).

CONCLUSION

This easy-to-implement and resource-saving approach has the potential to increase vaccination rates in oncological patients and to have a considerable impact protecting oncological patients from preventable infectious diseases.

CLINICAL TRIAL REGISTRATION

The study was registered at the German Resister for Clinical Studies (DRKS) under DRKS00020118.

Vaccination Coverage among Immunocompromised Patients in a Large Health Maintenance Organization: Findings from a Novel Computerized Registry

Immune-compromised patients (IPs) are at high risk for infections, some of which are preventable by vaccines. Specific vaccines are recommended for IP; however, the vaccination rate is suboptimal. The aim of this study is to describe the development of an IP registry and to assess vaccination rates in this population. A population-based registry of IPs was developed using an automated extraction of patient electronic health-record data in Maccabi Healthcare Services (MHS), an Israeli health maintenance organization serving over 2.4 million members. Included in the registry were patients receiving immunosuppressive therapy (IT); patients living with HIV (PLWH); solid organ and bone marrow transplant recipients (TR); patients with advanced kidney disease (AKD), and asplenic patients. We evaluated the full schedule for each vaccine's uptake rates for influenza, pneumococcal, meningococcal, and hepatitis B. On 1 October 2019, 32,637 adult immune-compromised patients were identified by the registry. Of them, 1647 were PLWH; 2354 were asplenic; 5317 had AKD; 23,216 were on IT; and 1824 were TR. Their mean age was 57 and 52.4% were females. The crude rate of immune compromise among adult MHS members was 2%. Vaccine coverage rate was overall low for PCV13, with only 11.9% of all IPs in the registry having received one dose. Influenza and PPV23 vaccination rates were higher (45% and 39.4%, respectively). Only 5.3% of all IPs received all three vaccines. Overall, low vaccination coverage was found among IPs. Our registry can serve to identify target-patient populations for interventions and monitor their effectiveness.

Vaccinations Status against Vaccine-Preventable Diseases and Willingness to Be Vaccinated in an Italian Sample of Frail Subjects

BACKGROUND

Study aim was to investigate the vaccination status against vaccine-preventable diseases (VPD) of frail adults during the SARS-CoV-2 pandemic and, for those subjects eligible for at least one vaccine, with respect to the recommended vaccination in line with the Italian National Vaccination Prevention Plane (NPVP), to explore the willingness to be vaccinated.

METHODS

A cross-sectional study was carried out among adults aged ≥ 60, immunocompromised or subjects affected by chronic conditions.

RESULTS

Among the 427 participants, a vaccination coverage rate lower than the targets for all the vaccines considered was found. Of those, 72.6% of subjects stated their willingness to receive recommended vaccinations, and 75.2% of the respondents stated that the advice to undergo vaccinations was received by the General Practitioner (GP). In a multivariable logistic regression model, higher odds of recommended VPD vaccination uptake (defined as having two or more of the recommended vaccinations) were associated with the willingness towards recommended VPD vaccination (Odds Ratio = 3.55, 95% Confidence Interval: 1.39 to 9.07), university education (OR = 2.03, 95% CI: 1.03 to 3.97), but having another person in the household (OR = 0.52, 95% CI: 0.28 to 0.97), and history of oncological disease (OR = 0.39, 95% CI: 0.18 to 0.87) were predictive of lower odds of vaccination uptake. In another multivariable model, higher odds of willingness to receive vaccines were associated with kidney disease (OR = 3.3, 95% CI: 1.01 to 10.5), perceived risk of VPD (OR = 1.9, 95% CI: 1.02 to 3.3), previous influenza vaccination (OR = 3.4, 95% CI: 1.8 to 6.5), and previous pneumococcal vaccination (OR = 3.1, 95% CI: 1.3 to 7.7), but increasing age (OR = 0.93 per year, 95% CI: 0.91 to 0.97), working (OR = 0.40, 95% CI: 0.20 to 0.78), and fear of vaccine side effects (OR = 0.38, 95% CI: 0.21 to 0.68) were predictive of lower odds of willingness to receive vaccines.

CONCLUSIONS

Despite specific recommendations, vaccination coverage rates are far below international targets for frail subjects. Reducing missed opportunities for vaccination could be a useful strategy to increase vaccination coverage in frail patients during the routine checks performed by GPs and specialists.

Understanding predictors of pneumococcal vaccine uptake in older adults aged 65 years and older in high-income countries across the globe: A scoping review

BACKGROUND

Pneumococcal disease causes substantial morbidity and mortality in older adults. Pneumococcal polysaccharide vaccine (PPV23) is routinely recommended to reduce the disease burden in this population. However, the vaccination coverage in older adults remains suboptimal in high-income countries.

OBJECTIVES

We sought to understand the current landscape of published literature on the predictors of pneumococcal vaccine uptake in older adults aged 65 years and older in high-income countries, and to identify the gaps in literature to inform future research.

METHODS

We conducted a scoping review employing the Arksey and O'Malley framework and Joanna Briggs Methods. We searched Medline, EMBASE, CINAHL, PsycInfo and Cochrane databases. We included quantitative and qualitative studies on predictors of pneumococcal vaccination in older adults that reported older adult- and pneumococcal vaccine-specific results, conducted in high-income settings, and published in English between January 2015 and April 2020. We excluded studies assessing interventions to improve vaccine uptake. We followed the Strategic Advisory Group of Experts on Immunization Working Group Vaccine Hesitancy Determinants Matrix to map the predictors within contextual, individual and social group, and vaccine and vaccination-specific influence determinants. Studies on providers and institutions were also included and results summarized separately.

RESULTS

We included 52 publications in our review. Most of the predictors in 39 quantitative studies belonged to the individual and social group influences (n = 12), followed by contextual influences (n = 11) and vaccine and vaccination-specific issues (n = 3). Few qualitative studies explored the barriers to pneumococcal vaccination. Only five studies examined predictors from the healthcare providers' perspective. Three studies examined the institutional characteristics as the predictors of pneumococcal vaccination in older adults.

CONCLUSIONS

We identified enablers and barriers of pneumococcal vaccination among older adults in high-income settings. We also identified gaps in the literature and provide recommendations for future research to address the gaps.

Incidence and Predictors of Community-Acquired Pneumonia in Patients With Hematological Cancers Between 2016 and 2019

Background

Patients with hematological cancers (HC) are at high risk of infections, in particular community-acquired pneumonia (CAP). Recent data on incidence and predictors of CAP among patients with HC are scarce.

Methods

We performed a cohort study (2016–2019) in 2 hospitals in the Netherlands among adults with HC to calculate incidence rates (IRs) of CAP. In addition, we performed a nested case-control study to identify predictors of CAP.

Results

We identified 275 CAP cases during 6264 patient-years of follow-up. The IR of CAP was 4390/100 000 patient-years of follow-up. Compared with the general population, IR ratios ranged from 5.4 to 55.3 for the different HCs. The case fatality and intensive care unit (ICU) admission rates were 5.5% and 9.8%, respectively. Predictors for CAP in patients with HC were male sex, anemia, lymphocytopenia, chronic kidney disease, cardiovascular disease, autologous and allogeneic stem cell transplantation, treatment with immunosuppressive medication for graft-vs-host disease, treatment with rituximab in the past year, and treatment with immunomodulators (lenalidomide, thalidomide, pomalidomide and/or methotrexate) in the past month. Independent predictors of a severe disease course (death or ICU admission) included neutropenia (odds ratio, 4.14 [95% confidence interval, 1.63–10.2]), pneumococcal pneumonia (10.24 [3.48–30.1]), chronic obstructive pulmonary disease (6.90 [2.07–23.0]), and the use of antibacterial prophylaxis (2.53 [1.05–6.08]).

Conclusions

The burden of CAP in patients with HC is high, with significant morbidity and mortality rates. Therefore, vaccination against respiratory pathogens early in the disease course is recommended, in particular before starting certain immunosuppressive therapies.

Influenza vaccination uptake and attitudes among adult cancer patients in Japan: a web-based questionnaire survey before the 2020/2021 season

Influenza vaccination is necessary to reduce severe influenza complications, especially in immunocompromised people such as cancer patients. However, few studies have examined influenza vaccination uptake among adult Japanese patients with cancer; their attitudes toward vaccination, as well as factors related to vaccine hesitancy, are unclear. From September 1 to October 31, 2020, we disseminated a web-based questionnaire to patients with a history of cancer via snowball sampling through e-mails and social media of two Japanese cancer patients associations. A total of 163 surveys were completed. One hundred (61.3%) participants received an influenza vaccination in the 2019/2020 season, and the main reasons for vaccination were as follows: recommendation by medical professionals, positive awareness of vaccination through books or the internet, and provision of vaccination in the workplace. The main reasons for not receiving a vaccination were fear of adverse events, lack of concern about influenza infection, and lack of trust in vaccine effectiveness. In terms of the 2020/2021 season, 120 participants (73.6%) reported their intention to receive an influenza vaccination. Multiple regression analysis showed that significant factors for positive intention were the the treatment without chemotherapy (p = .009), vaccination history in the 2019/2020 season (p < .001), prior experience of influenza infection (p = .043), and the perception that influenza vaccination was more important due to the coronavirus disease pandemic (p = .050). This preliminary survey revealed a relatively modest influenza vaccine coverage among adult Japanese patients with cancer and identified several factors related to positive intention toward vaccination.

Review of Influenza Virus Vaccines: The Qualitative Nature of Immune Responses to Infection and Vaccination Is a Critical Consideration

Influenza viruses have affected the world for over a century, causing multiple pandemics. Throughout the years, many prophylactic vaccines have been developed for influenza; however, these viruses are still a global issue and take many lives. In this paper, we review influenza viruses, associated immunological mechanisms, current influenza vaccine platforms, and influenza infection, in the context of immunocompromised populations. This review focuses on the qualitative nature of immune responses against influenza viruses, with an emphasis on trained immunity and an assessment of the characteristics of the host–pathogen that compromise the effectiveness of immunization. We also highlight innovative immunological concepts that are important considerations for the development of the next generation of vaccines against influenza viruses.

Vaccination in older adults with cancer and older cancer survivors

Vaccination is one of the most effective means of preventing infections and should be widely promoted, especially in immunocompromised patients, such as older adults with cancer and older cancer survivors. However, adherence is low, which is due in part to lack of awareness, fear of side effects, hesitancy to vaccinate and rejection of vaccination, especially for COVID-19. The objective of this paper is to clarify current indications for vaccination in these populations and underscore its importance.