Strategies to improve vaccination rates in people who are homeless: A systematic review

Global distribution and characteristics of pneumococcal serotypes in adults

The introduction of pneumococcal conjugate vaccines (PCVs) into pediatric national immunization programs (NIP) has significantly reduced invasive pneumococcal diseases and pneumococcal pneumonia caused by PCV serotypes in adults due to herd immunity. However, diseases caused by PCV13 serotypes persist, mainly serotype 3, known for its severity. With the reduction in PCV13 serotypes, diseases caused by non-PCV13 serotypes increased. Residual and emerging serotypes vary regionally; serotype 8 in Europe and South Africa, and serotype 4 in the US and Canada. PCV20 and PCV21 were recently developed, which can prevent residual and emerging pneumococcal diseases where herd immunity is well-established. In countries that have not introduced PCV into pediatric NIP, the pneumococcal disease burden due to PCV serotypes is still marked. Given that serotype distribution varies by region and evolves over time, this review aimed to discuss serotype distribution and disease severity in adults across countries to support future pneumococcal vaccine strategies.

COVID-19 vaccination uptake in people experiencing homelessness during the first three years of the global COVID-19 vaccination effort: A systematic review and meta-analysis

There are complex barriers to vaccination, including COVID-19 vaccination, in people experiencing homelessness. Consequently, it is likely COVID-19 vaccination uptake in this vulnerable population is lower than in general populations. This systematic review and meta-analysis reports COVID-19 vaccination uptake in people experiencing homelessness, including in comparison to general populations, in literature published during the first three years of the global COVID-19 vaccination effort. Searches were conducted on eight electronic databases. Peer-reviewed studies from high-income countries available in English and in full-text were considered for inclusion. Studies were considered up to 31 December 2023. In total 1884 studies were retrieved and, after removal of duplicates, 1167 were screened. Thirty-one studies were included in this review. For studies reporting uptake of either any, or first, COVID-19 vaccine a random effects meta-analysis was used to pool coverage estimates. It included 28 first vaccine dose coverage estimates from 18 studies including 104,139 vaccinated individuals in 308,253 participants. The pooled estimate for first dose vaccine coverage in people experiencing homelessness was 43 % (95 % CI: 35 %, 51 %). The 95 % prediction interval was (0, 88 %). Uptake of subsequent doses was heterogeneous and was reported narratively. Uptake of the second dose ranged upwards from 31.3 %, and uptake of the third dose was reported in one study as 7.2 %. COVID-19 vaccination uptake in people experiencing homelessness is lower than in general populations. Disparities in uptake persisted when comparing uptake at regional/state/national levels, at multiple timepoints, and in studies focused on different sub-populations including veterans. This is problematic, considering people experiencing homelessness are more likely to have poorer COVID-19-associated outcomes. It is important to recognise people experiencing homelessness are an at-risk, hard-to-reach group for vaccination, and vaccination strategies should be targeted to this population to improve uptake.

Utilization of street-based COVID-19 vaccination clinics in Phoenix's homeless population

The novel Coronavirus (COVID-19) is a highly contagious viral illness that has caused the most significant global health crisis in recent human history. Individuals experiencing homelessness represent one of the more vulnerable populations for COVID-19 infection and morbidity. Amongst individuals experiencing homelessness in Phoenix, a student-led interprofessional organization called Street Medicine Phoenix (SMP) sought to both reduce the risk of COVID-19 transmission and morbidity/mortality related to infection. Through collaborations with the Maricopa County Department of Public Health and various community organizations, SMP developed a format for street-based vaccination clinics. SMP deployed these clinics on numerous occasions to the streets directly surrounding the community homeless shelter, allowing SMP to vaccinate individuals directly in their encampments. Through SMP's efforts starting in February 2021, 400 individuals experiencing homelessness have received at least one COVID-19 vaccine. Challenges encountered included low health literacy, lack of established rapport and trust, low vaccine confidence, difficulty verifying patients' vaccination status, difficulty obtaining sufficient information from patients to create a record in the Arizona State Immunization Information System (ASIIS), monitoring patients post-vaccination, transporting vaccine supplies from encampment to encampment, and lack of patient awareness of the mobile vaccine clinic services. Despite challenges, SMP's outreach efforts have demonstrated the feasibility and importance of mobile public health services to reach homeless encampments, particularly mobile vaccination clinics in response to disease outbreaks, and the necessity of strategic partnerships with community agencies to effectively meet the needs of underserved populations.

Implementing a COVID-19 vaccination outreach service for people experiencing homelessness

ISSUE ADDRESSED

In 2021, the Australian government implemented a population wide COVID-19 vaccination program. People experiencing homelessness faced challenges accessing vaccines and many were not being reached. By reorienting vaccination services to include assertive outreach strategies, a Brisbane-based non-profit health care team successfully administered 2065 COVID-19 vaccinations to homeless and precariously housed people. This study examines insights from stakeholders delivering the service and perspectives of clients who received a vaccine.

METHODS

Semi-structured interviews with five stakeholders and a survey of 63 clients involved in the Micah Projects COVID-19 vaccination program are reported. Client survey questions covered demographic characteristics, and motivations and hesitancies around vaccination. Stakeholder interviews were inductively analysed and quantitative survey data were exported into SPSS (IBM V27) and analysed using descriptive statistics.

RESULTS

The Micah Projects team initiated 220 pop-up vaccination clinics and worked closely with Aboriginal and Torres Strait Islander communities. Downsizing and mobilising the service engaged greater numbers of people sleeping rough and Aboriginal and Torres Strait Islander people. Clients' decisions to vaccinate were often spontaneous, driven by immediate availability and motivated by a desire to stay healthy and protect the community.

CONCLUSIONS

Tailoring vaccination programs to include assertive outreach strategies effectively reduces barriers for people experiencing homelessness. Community embeddedness, trust, flexibility and cultural safety are critical elements for success. SO WHAT?: People experiencing homelessness are motivated to vaccinate. Reorientating health services to remove structural barriers and build the supportive environments needed to work through vaccine hesitancies are critical elements to ensure equitable access and promote health.

Tackling Inequalities in Access to Medicines for People Experiencing Homelessness: A Meta-Ethnography and Qualitative Systematic Review

INTRODUCTION

Despite increased awareness of the detrimental relationship between homelessness and health, people experiencing homelessness remain an underserved population in health and social care research. Due to barriers affecting the accessibility of medicine and healthcare services, as well as reported competing priorities such as food and shelter, evidence has demonstrated that people experiencing homelessness are less likely to undergo routine examinations, receive diagnoses and adhere to prescribed medical treatments. To enhance service design and access for those experiencing homelessness, it is critical to better recognise, understand and address the barriers these individuals face. This meta-ethnography aims to identify barriers, enablers and interventions to begin addressing this inequality gap.

METHODS

A systematic literature search was undertaken in October and re-ran in December 2023 across four databases: MEDLINE, Embase, CINAHL and Scopus. Qualitative studies were included if they addressed barriers, enablers and interventions aimed at tackling medicines and health service inequalities among populations experiencing homelessness. Study quality was assessed using the Joanna Briggs Institute critical appraisal checklist. Data were synthesised using a meta-ethnographic approach, as outlined by Noblit and Hare. The review was registered on PROSPERO (CRD42024511502) and performed according to PRISMA guidelines.

RESULTS

This meta-ethnographic systematic review synthesised data from eight studies across multiple countries. Three overarching third-order constructs (termed 'themes') were developed through reciprocal translation and centred around: recognising and acknowledging the discrimination, stigma and barriers experienced when using current services; exploring safe and practical use of medicines and the promotion of general health education and appreciating strategies to tackle inequalities, namely community outreach programmes designed for homeless communities.

CONCLUSION

This work highlighted the barriers, enablers and interventions that sought to address the inequalities affecting people experiencing homelessness in accessing medication and healthcare services. Future research should utilise lived-experience narratives and co-design to further explore ways to tackle wider healthcare accessibility inequalities for this minoritised population.

TRIAL REGISTRATION

Not applicable, as this is a systematic review.

PATIENT OR PUBLIC CONTRIBUTION

Public contributors (minority research champions and one public health research champion, H.K.G. and T.G.) informed and shaped this project during study design and conceptualisation. They helped to ensure that the study was conducted, and the findings were reported with sensitivity.

Colocation of COVID-19 Vaccination Services at Syringe Service Programs for People Who Inject Drugs and People Experiencing Houselessness in Oregon

OBJECTIVES

Integrating vaccination services with other essential health services could increase vaccination rates among socially marginalized populations. We examined the associations between colocation of vaccines at syringe service programs and COVID-19 vaccination status among people who inject drugs and people experiencing houselessness.

METHODS

This study included 1891 participants aged ≥18 years at 9 sites in Oregon from July 2021 through March 2022. Participants self-reported whether they had ever received ≥1 dose of a COVID-19 vaccine. We calculated site-level COVID-19 vaccine availability and overall vaccination rates. We compared site-level vaccination rates and analyzed the association between vaccine availability and vaccination status.

RESULTS

We found no significant difference in vaccination rates between sites that did and did not offer COVID-19 vaccines (t7 = -0.33; P = .75). We also found no significant association between vaccine availability and vaccination status. However, the odds of having received a COVID-19 vaccine were 2.79 times higher for each additional site visit during which COVID-19 vaccines were available (odds ratio [OR] = 2.79; 95% CI, 2.18-3.58; P < .001). The association between vaccine availability and vaccine status was not moderated by participant age (OR = 1.03; 95% CI, 0.99-1.07; P = .13) or housing instability (OR = 0.59; 95% CI, 0.13-2.60; P = .48).

CONCLUSIONS

Colocating COVID-19 vaccines at syringe service programs was only positively associated with vaccination status if vaccines were offered frequently on-site. Future work should examine whether the frequency of offering vaccination services increases willingness to engage in vaccination and examine trust and convenience as potential mechanisms.

Impact of COVID-19 on individuals experiencing homelessness: Lessons learned and recommendations for practitioners

The COVID-19 pandemic, which brought about unprecedented changes globally, shed light on the significant disparities faced by persons experiencing homelessness (PEH). These individuals faced an elevated risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to factors such as lack of safe housing, limited access to hygiene and sanitation, and communal living situations. The unique challenges, vulnerabilities, and effects of COVID-19 on PEH is discussed, as well as lessons learned from these experiences, recommendations for practitioners, and the ongoing implications for addressing homelessness.

Infectious Diseases Among People Experiencing Homelessness: A Systematic Review of the Literature in the United States and Canada, 2003-2022

Homelessness increases the risk of acquiring an infectious disease. We conducted a systematic review of the literature to identify quantitative data related to infectious diseases and homelessness. We searched Google Scholar, PubMed, and SCOPUS for quantitative literature published from January 2003 through December 2022 in English from the United States and Canada. We excluded literature on vaccine-preventable diseases and HIV because these diseases were recently reviewed. Of the 250 articles that met inclusion criteria, more than half were on hepatitis C virus or Mycobacterium tuberculosis. Other articles were on COVID-19, respiratory syncytial virus, Staphylococcus aureus, group A Streptococcus, mpox (formerly monkeypox), 5 sexually transmitted infections, and gastrointestinal or vectorborne pathogens. Most studies showed higher prevalence, incidence, or measures of risk for infectious diseases among people experiencing homelessness as compared with people who are housed or the general population. Although having increased published data that quantify the infectious disease risks of homelessness is encouraging, many pathogens that are known to affect people globally who are not housed have not been evaluated in the United States or Canada. Future studies should focus on additional pathogens and factors leading to a disproportionately high incidence and prevalence of infectious diseases among people experiencing homelessness.

The Burden of Hepatitis A Outbreaks in the United States: Health Outcomes, Economic Costs, and Management Strategies

BACKGROUND

Hepatitis A (HepA) vaccines are recommended for US adults at risk of HepA. Ongoing United States (US) HepA outbreaks since 2016 have primarily spread person-to-person, especially among at-risk groups. We investigated the health outcomes, economic burden, and outbreak management considerations associated with HepA outbreaks from 2016 onwards.

METHODS

A systematic literature review was conducted to assess HepA outbreak-associated health outcomes, health care resource utilization (HCRU), and economic burden. A targeted literature review evaluated HepA outbreak management considerations.

RESULTS

Across 33 studies reporting on HepA outbreak-associated health outcomes/HCRU, frequently reported HepA-related morbidities included acute liver failure/injury (n = 6 studies of 33 studies) and liver transplantation (n = 5 of 33); reported case fatality rates ranged from 0% to 10.8%. Hospitalization rates reported in studies investigating person-to-person outbreaks ranged from 41.6% to 84.8%. Ten studies reported on outbreak-associated economic burden, with a national study reporting an average cost of over $16 000 per hospitalization. Thirty-four studies reported on outbreak management; challenges included difficulty reaching at-risk groups and vaccination distrust. Successes included targeted interventions and increasing public awareness.

CONCLUSIONS

This review indicates a considerable clinical and economic burden of ongoing US HepA outbreaks. Targeted prevention strategies and increased public awareness and vaccination coverage are needed to reduce HepA burden and prevent future outbreaks.

Immunity against measles, mumps, rubella, and varicella among homeless individuals in Germany - A nationwide multi-center cross-sectional study

Introduction

Homeless individuals suffer a high burden of vaccine-preventable infectious diseases. Moreover, they are particularly susceptible to adverse infection outcomes with limited access to the health care system. Data on the seroprevalence of measles, mumps, rubella, and varicella within this cohort are missing.

Methods

The seroprevalence of measles, mumps, rubella, and varicella was determined within the homeless population in Germany. Predictors of lacking immune protection were determined using multivariable logistic regression analysis.

Results

Homeless individuals in Germany (n = 611) showed a seroprevalence of 88.5% (95% CI: 85.8-91.0) for measles, 83.8% (95% CI: 80.6-86.6) for mumps, 86.1% (95% CI: 83.1-88.7) for rubella, and 95.7% (95% CI 93.8-97.2) for varicella. Measles seroprevalences declined from individuals born in 1965 to individuals born in 1993, with seroprevalences not compatible with a 95% threshold in individuals born after 1980. For mumps, seroprevalences declined from individuals born in 1950 to individuals born in 1984. Here, seroprevalences were not compatible with a 92% threshold for individuals born after 1975. Seronegativity for measles, mumps and rubella was associated with age but not with gender or country of origin.

Discussion

Herd immunity for measles and mumps is not achieved in this homeless cohort, while there was sufficient immune protection for rubella and varicella. Declining immune protection rates in younger individuals warrant immunization campaigns also targeting marginalized groups such as homeless individuals. Given that herd immunity thresholds are not reached for individuals born after 1980 for measles, and after 1975 for mumps, vaccination campaigns should prioritize individuals within these age groups.

The effect of a financial incentive on COVID-19 vaccination uptake, and predictors of uptake, in people experiencing homelessness: A randomized controlled trial

People who are homeless are at increased risk of COVID-19 infection, and of poorer associated outcomes. Delivering vaccinations to, and ensuring uptake of multiple doses in, people who are homeless is complex. Financial incentives may improve vaccination uptake, particularly in people who have not received routine vaccinations previously, though evidence about the effect of incentives is limited and variable. This randomized controlled trial (ANZCTR 383156) assessed the effect of a financial incentive (an A$10 grocery voucher) on uptake of the second COVID-19 vaccination in Australian adults who were homeless, and who had received their first dose. Participants were recruited through a vaccination program for people experiencing homelessness between September 2021 and January 2022. They were followed-up for a minimum of 6.5 months. Uptake was measured 'on-time' at 6 weeks, and at any time during the trial period. Vaccination status was checked on the Australian Immunisation Register. Demographic and vaccination program characteristics associated with uptake were also investigated. Eighty-six people consented to participate, and 43 were randomly allocated to each of the 'incentive' and 'no incentive' groups. The incentive slightly increased the likelihood of a participant receiving a second vaccination on-time (risk difference (RD), 11.6 % [95 %CI, -9.0, 32.2 %]; p = 0.27), and at any time during the trial (RD, 14.0 % [95 %CI, -2.2, 30.1 %], p = 0.09). The incentive had a significant positive effect on uptake in people with no previous vaccination history, increasing their likelihood of receiving a second vaccination on-time (RD, 42.3 % [95 %CI, 15.7, 68.8 %]; p = 0.002) and at any time during the trial (RD, 38.7 % [95 %CI, 16.1, 61.3 %], p < 0.001). Financial incentives may increase COVID-19 vaccination uptake in people who are homeless, and particularly those who have no previous vaccination history. Future research should consider alternative incentive values, types, and cost-effectiveness.

Respiratory Syncytial Virus, Influenza and SARS-CoV-2 in Homeless People from Urban Shelters: A Systematic Review and Meta-Analysis (2023)

Homeless people (HP) are disproportionally affected by respiratory disorders, including pneumococcal and mycobacterial infections. On the contrary, more limited evidence has been previously gathered on influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and very little is known about the occurrence of human respiratory syncytial virus (RSV), a common cause of respiratory tract infections among children and the elderly. The present systematic review was designed to collect available evidence about RSV, influenza and SARS-CoV-2 infections in HP, focusing on those from urban homeless shelters. Three medical databases (PubMed, Embase and Scopus) and the preprint repository medRxiv.org were therefore searched for eligible observational studies published up to 30 December 2023, and the collected cases were pooled in a random-effects model. Heterogeneity was assessed using the I2 statistics. Reporting bias was assessed by funnel plots and a regression analysis. Overall, 31 studies were retrieved, and of them, 17 reported on the point prevalence of respiratory pathogens, with pooled estimates of 4.91 cases per 1000 HP (95%CI: 2.46 to 9.80) for RSV, 3.47 per 1000 HP for influenza and 40.21 cases per 1000 HP (95%CI: 14.66 to 105.55) for SARS-CoV-2. Incidence estimates were calculated from 12 studies, and SARS-CoV-2 was characterized by the highest occurrence (9.58 diagnoses per 1000 persons-months, 95%CI: 3.00 to 16.16), followed by influenza (6.07, 95%CI: 0.00 to 15.06) and RSV (1.71, 95%CI: 0.00 to 4.13). Only four studies reported on the outcome of viral infections in HP: the assessed pathogens were associated with a high likelihood of hospitalization, while high rates of recurrence and eventual deaths were reported in cases of RSV infections. In summary, RSV, influenza and SARS-CoV-2 infections were documented in HP from urban shelters, and their potential outcomes stress the importance of specifically tailored preventive strategies.

Invasive Pneumococcal Disease and Potential Impact of Pneumococcal Conjugate Vaccines Among Adults, Including Persons Experiencing Homelessness-Alaska, 2011-2020

BACKGROUND

Adults aged ≥65 years, adults with certain underlying medical conditions, and persons experiencing homelessness are at increased risk for invasive pneumococcal disease (IPD). Two new pneumococcal conjugate vaccines, 15-valent pneumococcal conjugate vaccine (PCV15) and 20-valent pneumococcal conjugate vaccine (PCV20), were recently approved for use in US adults. We describe the epidemiology of IPD among Alaska adults and estimate the proportion of IPD cases potentially preventable by new vaccines.

METHODS

We used statewide, laboratory-based surveillance data to calculate and compare IPD incidence rates and 95% confidence intervals (CIs) among Alaska adults aged ≥18 years during 2011-2020 and estimate the proportion of IPD cases that were caused by serotypes in PCV15 and PCV20.

RESULTS

During 2011-2020, 1164 IPD cases were reported among Alaska adults for an average annual incidence of 21.3 cases per 100 000 adults per year (95% CI, 20.1-22.5). Incidence increased significantly during the study period (P < .01). IPD incidence among Alaska Native adults was 4.7 times higher than among non-Alaska Native adults (95% CI, 4.2-5.2). Among adults experiencing homelessness in Anchorage, IPD incidence was 72 times higher than in the general adult population (95% CI, 59-89). Overall, 1032 (89%) Alaska adults with IPD had an indication for pneumococcal vaccine according to updated vaccination guidelines; 456 (39%) and 700 (60%) cases were caused by serotypes in PCV15 and PCV20, respectively.

CONCLUSIONS

Use of PCV15 and PCV20 could substantially reduce IPD among adults in Alaska, including Alaska Native adults and adults experiencing homelessness.

Vaccine acceptance, determinants, and attitudes toward vaccine among people experiencing homelessness: a systematic review and meta-analysis

BACKGROUND

COVID-19 has caused millions of deaths globally, with vulnerable populations such as people experiencing homelessness (PEH) at higher risk. This systematic review and meta-analysis aims to identify the prevalence and key factors contributing to vaccine acceptance experienced by PEH.

METHODS

The protocol of this study was registered in PROSPERO (CRD42023391659). We included studies that reported relevant information about vaccine acceptance or vaccine hesitant/refusal among PEH. Eight databases were systematically searched in January 2023. Meta-analysis was conducted for the prevalence of vaccine acceptance, vaccine uptake, and factors associated with vaccine acceptance. Attitudes toward vaccines were combined into bar charts.

RESULT

A total of 29 papers were included in this systematic review and 19 papers were included for meta-analysis. The pooled prevalence of COVID-19 vaccine acceptance among PEH was 66% (95%CI: 58%-73%). Our meta-regression showed vaccine acceptance was significantly increased over time. Moreover, subgroup meta-analysis showed that PEH were more likely to accept the COVID-19 vaccine after June 2021 (78%, 95%CI: 65%-86%) compared with earlier period (56%, 95%CI: 54%-59%). Subgroup meta-analysis also revealed that women and participants without underlying medical condition (chronic diseases) were significantly less likely to accept the COVID-19 vaccine, compared to men and those with medical conditions, respectively.

CONCLUSION

The study emphasizes the need for targeted public health interventions aimed at increasing vaccine acceptance among PEH, especially at the early stage of the pandemic, among females, those without underlying medical conditions, being Black (in Canada and the USA), and young people. These interventions should address the common concerns of vaccine safety, adverse effects, effectiveness, and distrust in health care systems. In addition to offering vaccinations in different areas convenient to them, education programs could be established to increase vaccine acceptance among PEH.

Dimensions of equality in uptake of COVID-19 vaccination in Wales, UK: A multivariable linked data population analysis

Vaccination has proven to be effective at preventing severe outcomes of COVID-19 infection, and uptake in the population has been high in Wales. However, there is a risk that high-level vaccination coverage statistics may mask hidden inequalities in under-served populations, many of whom may be at increased risk of severe outcomes of COVID-19 infection. The study population included 1,436,229 individuals aged 18 years and over, alive and residence in Wales as at 31st July 2022, and excluded immunosuppressed or care home residents. We compared people who had received one or more vaccinations to those with no vaccination using linked data from nine datasets within the Secure Anonymised Information Linkage (SAIL) databank. Multivariable analysis was undertaken to determine the impact of a range of sociodemographic characteristics on vaccination uptake, including ethnicity, country of birth, severe mental illness, homelessness and substance use. We found that overall uptake of first dose of COVID-19 vaccination was high in Wales (92.1 %), with the highest among those aged 80 years and over and females. Those aged under 40 years, household composition (aOR 0.38 95 %CI 0.35-0.41 for 10+ size household compared to two adult household) and being born outside the UK (aOR 0.44 95 %CI 0.43-0.46) had the strongest negative associations with vaccination uptake. This was followed by a history of substance misuse (aOR 0.45 95 %CI 0.44-0.46). Despite high-level population coverage in Wales, significant inequalities remain across several underserved groups. Factors associated with vaccination uptake should not be considered in isolation, to avoid drawing incorrect conclusions. Ensuring equitable access to vaccination is essential to protecting under-served groups from COVID-19 and further work needs to be done to address these gaps in coverage, with focus on tailored vaccination pathways and advocacy, using trusted partners and communities.

Differences in meningococcal disease incidence by health insurance type and among persons experiencing homelessness-United States, 2016-2019

Meningococcal disease is a serious but rare disease in the United States. Prior publications suggest incidence differs among privately vs publicly-insured persons, and that incidence is higher among persons experiencing homelessness (PEH) than persons not known to be experiencing homelessness (non-PEH). Using insurance claims data for persons aged <1 to 64 years, we calculated meningococcal disease incidence among a population with employer-sponsored commercial insurance and persons enrolled in state Medicaid programs nationwide. We also examined meningococcal disease incidence by PEH status in Medicaid data. From 2016 through 2019, persons who met our study inclusion criteria contributed a total of 84,460,548 person-years (PYs) to our analysis of commercial insurance data and 253,496,622 PYs to our analysis of Medicaid data. Incidence was higher among persons enrolled in Medicaid (0.12 cases per 100,000 PYs) than persons with commercial insurance (0.06 cases per 100,000 PYs). Incidence was 3.17 cases per 100,000 PYs among PEH in Medicaid, 27 times higher than among non-PEH in Medicaid. Understanding the underlying drivers of the higher meningococcal disease incidence among PEH and persons enrolled in Medicaid may inform prevention strategies for populations experiencing a higher burden of disease.

Vaccination, human mobility, and COVID-19 health outcomes: Empirical comparison before and during the outbreak of SARS-Cov-2 B.1.1.529 (Omicron) variant

The B.1.1.529 (Omicron) variant surge has raised concerns about the effectiveness of vaccines and the impact of imprudent reopening. Leveraging over two years of county-level COVID-19 data in the US, this study aims to investigate relationships among vaccination, human mobility, and COVID-19 health outcomes (assessed via case rate and case-fatality rate), controlling for socioeconomic, demographic, racial/ethnic, and partisan factors. A set of cross-sectional models was first fitted to empirically compare disparities in COVID-19 health outcomes before and during the Omicron surge. Then, time-varying mediation analyses were employed to delineate how the effects of vaccine and mobility on COVID-19 health outcomes vary over time. Results showed that vaccine effectiveness against case rate lost significance during the Omicron surge, while its effectiveness against case-fatality rate remained significant throughout the pandemic. We also documented salient structural inequalities in COVID-19-related outcomes, with disadvantaged populations consistently bearing a larger brunt of case and death tolls, regardless of high vaccination rates. Last, findings revealed that mobility presented a significantly positive relationship with case rates during each wave of variant outbreak. Mobility substantially mediated the direct effect from vaccination to case rate, leading to a 10.276 % (95 % CI: 6.257, 14.294) decrease in vaccine effectiveness on average. Altogether, our study implies that sole reliance on vaccination to halt COVID-19 needs to be re-examined. Well-resourced and coordinated efforts to enhance vaccine effectiveness, mitigate health disparity and selectively loosen non-pharmaceutical interventions are essential to bringing the pandemic to an end.

Determinants of depression and anxiety in homeless people: A population survey of homeless people in Hong Kong

BACKGROUND

There are growing concerns about the homeless and mental health issues globally. This study aims to examine the mental health situation of homelessness and the determinants of anxiety and depression of them in Hong Kong.

METHOD

The data from the largest territory-wide study of the homeless population in 2021 was analyzed. Descriptive statistics and logistic regressions were used to investigate the association between mental health and socioeconomic variables, including demographic background, economic indicators, COVID-19 worries, government measures, and respect by others. The symptoms of depression and anxiety were assessed using Patient Health Questionnaire (PHQ) and General Anxiety Disorder (GAD).

RESULTS

The results showed that being female, food insecurity, and chronic diseases were the risk factors for anxiety and depression. A high level of respect by others was the protective factor for depression (adjusted OR 0.37, 95% CI [0.23, 0.61]) and anxiety (adjusted OR 0.40, 95% CI [0.24, 0.68]), compared to a low level of respect in the multivariate model.

CONCLUSIONS

Providing medical outreach services, additional resources for social services, implementation of homeless-friendly policies, and a progressive supply of public and transitional housing would help enhance the well-being of the homeless population.

Health Care of People Experiencing Homelessness: Part I

Homelessness and Health CarePeople who experience homelessness have high rates of medical illness. They struggle with conditions associated with living in crowded shelters, trauma, and exposure to extreme weather. Here, Taylor and Munson review the care of this vulnerable population.

The Importance of Mapping Determinants, Attitudes and Beliefs of Vaccine Hesitancy in the Great Challenge of Compulsory Childhood Vaccination Comment on "Convergence on Coercion: Functional and Political Pressures as Drivers of Global Childhood Vaccine Mandates"

Vaccine hesitancy (VH) has risen significantly during the COVID-19 pandemic, becoming a major global health concern. VH is characterized by the delay or refusal of vaccination despite its availability. Various frameworks have been developed to understand the complex factors influencing VH, with attitudes, beliefs, and external influences being the most significant. The surge in VH has reignited the debate on the best approach to address it: persuasive/ educational or coercive. Attwell and Hannah studied the political and social reasons behind the adoption of mandatory vaccination in four jurisdictions (Italy, France, Australia, and California) due to declining vaccine coverage below the safety threshold. However, these methods may foster parental disbeliefs and opposition to vaccination campaigns. To combat VH, it is crucial to systematically assess its determinants within specific contexts and population groups. Increasing awareness about vaccination benefits, engaging with social media, and employing tailored strategies can foster spontaneous adherence to vaccination programs, eliminating the need for coercive measures.

Addressing vaccine-preventable encephalitis in vulnerable populations

PURPOSE OF REVIEW

Vaccinations have been pivotal in lowering the global disease burden of vaccine-preventable encephalitides, including Japanese encephalitis, tick-borne encephalitis, measles encephalitis, and rabies encephalitis, among others.

RECENT FINDINGS

Populations vulnerable to vaccine-preventable infections that may lead to encephalitis include those living in endemic and rural areas, military members, migrants, refugees, international travelers, younger and older persons, pregnant women, the immunocompromised, outdoor, healthcare and laboratory workers, and the homeless. There is scope for improving the availability and distribution of vaccinations, vaccine equity, surveillance of vaccine-preventable encephalitides, and public education and information.

SUMMARY

Addressing these gaps in vaccination strategies will allow for improved vaccination coverage and lead to better health outcomes for those most at risk for vaccine-preventable encephalitis.

Pharmacist-Led Implementation of Brief Tobacco Cessation Interventions during Mobile Health Access Events

To address gaps in care for individuals from under-resourced communities disproportionately affected by tobacco use, this pharmacist-led demonstration project evaluated the feasibility of implementing tobacco use screening and brief cessation interventions during mobile health access events. A brief tobacco use survey was administered verbally during events at two food pantries and one homeless shelter in Indiana to assess the interest and potential demand for tobacco cessation assistance. Individuals currently using tobacco were advised to quit, assessed for their readiness to quit, and, if interested, offered a tobacco quitline card. Data were logged prospectively, analyzed using descriptive statistics, and group differences were assessed by site type (pantry versus shelter). Across 11 events (7 at food pantries and 4 at the homeless shelter), 639 individuals were assessed for tobacco use (n = 552 at food pantries; n = 87 at the homeless shelter). Among these, 189 self-reported current use (29.6%); 23.7% at food pantries, and 66.7% at the homeless shelter (p < 0.0001). About half indicated readiness to quit within 2 months; of these, 9 out of 10 accepted a tobacco quitline card. The results suggest that pharmacist-led health events at sites serving populations that are under-resourced afford unique opportunities to interface with and provide brief interventions for people who use tobacco.

Results from a test-and-treat study for influenza among residents of homeless shelters in King County, WA: A stepped-wedge cluster-randomized trial

BACKGROUND

Persons experiencing homelessness face increased risk of influenza as overcrowding in congregate shelters can facilitate influenza virus spread. Data regarding on-site influenza testing and antiviral treatment within homeless shelters remain limited.

METHODS

We conducted a cluster-randomized stepped-wedge trial of point-of-care molecular influenza testing coupled with antiviral treatment with baloxavir or oseltamivir in residents of 14 homeless shelters in Seattle, WA, USA. Residents ≥3 months with cough or ≥2 acute respiratory illness (ARI) symptoms and onset <7 days were eligible. In control periods, mid-nasal swabs were tested for influenza by reverse transcription polymerase chain reaction (RT-PCR). The intervention period included on-site rapid molecular influenza testing and antiviral treatment for influenza-positives if symptom onset was <48 h. The primary endpoint was monthly influenza virus infections in the control versus intervention periods. Influenza whole genome sequencing was performed to assess transmission and antiviral resistance.

RESULTS

During 11/15/2019-4/30/2020 and 11/2/2020-4/30/2021, 1283 ARI encounters from 668 participants were observed. Influenza virus was detected in 51 (4%) specimens using RT-PCR (A = 14; B = 37); 21 influenza virus infections were detected from 269 (8%) intervention-eligible encounters by rapid molecular testing and received antiviral treatment. Thirty-seven percent of ARI-participant encounters reported symptom onset < 48 h. The intervention had no effect on influenza virus transmission (adjusted relative risk 1.73, 95% confidence interval [CI] 0.50-6.00). Of 23 influenza genomes, 86% of A(H1N1)pdm09 and 81% of B/Victoria sequences were closely related.

CONCLUSION

Our findings suggest feasibility of influenza test-and-treat strategies in shelters. Additional studies would help discern an intervention effect during periods of increased influenza activity.

Hepatitis B immunity among undergraduate nursing students: A brief report

BACKGROUND

Health sciences students who report low/equivocal hepatitis B titers may be required to repeat the immunization series, even though the result may not indicate non-immunity.

METHOD

To describe hepatitis B immunity patterns, this retrospective, descriptive study utilized de-identified vaccination records and anti-HBs titers of three cohorts of sophomore nursing students entering clinical rotations in 2018-2019.

RESULTS

Only 33% of students had initial anti-HBs quantitative serum titer ≥10 mIU/ml, demonstrating immunity. After students with low/equivocal titers (n = 191, 64%) were re-immunized per institution protocol, only 2% (n = 7) were identified as non-responders. Cumulative costs incurred by students for revaccination and repeat titer exceeded $20,000, with a process time of up to 8 months.

CONCLUSION

While rates of exposure to hepatitis B in acute care settings have steadily declined in the United States, students who go on to practice in community and public health settings have increased risk of exposure. Following best practices in demonstrating hepatitis B immunity, which include a single challenge dose followed by titer 4 weeks later, would decrease per student costs, wait time, and administrative burden associated with documentation and student counseling.

Immunization Coverage in Young People Experiencing Homelessness and the Impact of a Nurse-led Program

OBJECTIVES

To identify the proportion of young people experiencing homelessness who are immunized against vaccine-preventable diseases, and to evaluate the impact of a nurse-led immunization program to improve vaccination coverage in this population.

METHODS

A retrospective audit of electronic medical records included 400 participants aged 15 to 24 years who had an encounter with the Young People's Health Service, a nurse-led clinic co-located with a specialist youth homelessness service in Melbourne, Australia, between February 2019 and May 2021.

RESULTS

Integrating an immunization nurse within a youth specialist homelessness service increased the percentage of young people who were up-to-date with routine vaccinations from 6.0% (n = 24) to 38.8% (n = 155). Intersecting social determinants of health that increased participants' risk of vaccine preventable diseases, and of missing routine vaccines, were common.

CONCLUSIONS

Incomplete coverage of routine vaccines is common in young people accessing homelessness services, and this coverage was improved when young people encountered an immunization nurse while accessing support from a specialist youth homelessness service. As a service model, nurse-led community health clinics co-located within homelessness providers can improve vaccination coverage, and therefore health outcomes, of young people experiencing or at risk of homelessness.

Determinants of COVID-19 vaccine acceptance and access among people experiencing homelessness in Germany: A qualitative interview study

Introduction

People experiencing homelessness face lower life expectancy, higher prevalence of somatic and mental diseases and a more difficult access to healthcare compared to people in secure living. During the COVID-19 pandemic transmission rates were higher among people experiencing homelessness and preventive public health measures were not properly adapted to the specific needs of people experiencing homelessness. Thus, goal of our study was understanding the determinants of acceptability and access of the COVID-19 vaccine.

Materials and methods

We conducted a qualitative interview study with twenty guideline interviews with adult people currently experiencing homelessness in Berlin, Germany (August 2021 - April 2022). Participants were approached in a purposive sampling strategy. The interviews were analyzed with qualitative content analysis according to Mayring.

Results

Acceptance and attitude toward the COVID-19 vaccine is influenced by confidence in the vaccine as well as in the political and healthcare system, the individual COVID-19 risk perception and sense of collective responsibility. Overall, the acceptance of the vaccine was high among our participants. Facilities offering low threshold COVID-19 vaccines for people experiencing homelessness were perceived as helpful. Language barriers and the need for identity documents were major barriers to access the COVID 19 vaccine.

Discussion

People experiencing homelessness are a marginalized and vulnerable group often underrepresented in the public and scientific discourse. During the COVID-19 pandemic, preventive public health measures, including the COVID-19 vaccine, failed to consider specific needs of people experiencing homelessness. Multidimensional strategy to enhance inclusive healthcare are needed to improve access and to reduce discrimination and stigmatization.

Mpox Case Reports in an Urban Homeless Population and a Proof of Concept for a Street-Based Mobile Mpox Vaccination Clinic

Mpox is a new public health outbreak that particularly threatens the homeless population. Street Medicine Phoenix (SMP) is a student-led interprofessional volunteer organization that provides medical care and other essential services to individuals experiencing homelessness in Phoenix, Arizona. In addition to core services such as wound care; health screenings (blood pressure and blood glucose.); vision screenings; HIV testing; naloxone education and distribution; flu, COVID-19, and Hepatitis A vaccinations; and community resource referrals, SMP began offering mpox education and vaccination at outreach events. During an outreach event shortly after the onset of the mpox outbreak, SMP identified 2 suspected mpox cases. Accordingly, SMP has partnered with the Maricopa County Public Health Department to set up mobile mpox vaccination clinics on the streets outside of Phoenix Arizona's largest homeless shelter. We share the details of these 2 cases along with our early efforts vaccinating individuals experiencing homelessness for mpox via our mobile vaccination clinic. Our experiences demonstrate the importance of community agencies providing direct outreach to underserved populations where they are at, particularly the homeless population, to address public health concerns such as emerging disease outbreaks like mpox. In addition, these cases highlight the potential significant impact that street medicine programs can have on their respective homeless communities in the context of infectious disease mitigation and emphasize the importance of partnerships with local health departments.

Vaccine confidence among people who use drugs: A cross-sectional survey

Adult immunization coverage remains low in the US, particularly for people who use drugs (PWUD), a population that experiences a disproportionate burden of vaccine-preventable diseases. The extent of and characteristics associated with vaccine confidence (VC) held by PWUD is poorly understood. As VC strongly correlates with vaccine uptake, this cross-sectional study identifies mutable factors associated with VC and quantifies its relationship to immunization status within a highly vulnerable, underimmunized population of PWUD. Using a community-engaged research strategy with select partner organizations hosting syringe exchange programs in Atlanta, Los Angeles, and Las Vegas, USA, we surveyed participants ages 18-69 years served by these organizations from 2019 to 2020. Survey measures included sociodemographics, health behavior including immunization receipt, and vaccine confidence in adult vaccinations using a modified Emory Vaccine Confidence Index (EVCI). The findings reflect relatively low VC among the 1,127 recruited participants, with 56% expressing low VC (EVCI 0-12), 35% medium (EVCI 13-20) and 10% high (EVCI 21-24). EVCI varied by city, with lowest confidence in Atlanta and highest in Las Vegas. VC was associated with past receipt of specific vaccines, including hepatitis A, MMR, Tdap, and influenza. VC varied by specific sociodemographic correlates such as housing insecurity (reduced confidence) and receipt of public benefits or disability (increased confidence). This study identified correlates associated with VC based on site and sociodemographic characteristics for this priority population, highlighting the need for specific interventions to raise VC among PWUD, especially among those experiencing housing insecurity and without public benefits.

COVID-19 Vaccine Hesitancy among U.S. Veterans Experiencing Homelessness in Transitional Housing

Little is known about COVID-19 vaccine hesitancy and acceptance among individuals experiencing homelessness, despite their higher risk for morbidity and mortality from SARS-CoV-2. This study examines COVID-19 vaccination attitudes and uptake among U.S. military Veterans experiencing homelessness enrolled in transitional housing programs funded by the U.S. Department of Veterans Affairs (VA). Telephone interviews were conducted with 20 Veterans in California, Florida, Iowa, Kentucky, and Massachusetts, USA (January-April 2021). A rapid analysis approach was used to identify and enumerate commonly occurring themes. Although 60% of interviewed Veterans either received the COVID-19 vaccine or were willing to do so, one-third expressed hesitancy to get vaccinated. COVID-19 vaccination attitudes (e.g., belief that the vaccines were inadequately tested), military experience, beliefs about influenza and other vaccines, and sources of information emerged as influential factors for COVID-19 vaccination uptake or hesitancy. Veterans in VA-funded homeless transitional housing programs are generally willing to be vaccinated. However, a substantial minority is reluctant to take the vaccine due to concerns about the COVID-19 vaccine and distrust of authority. Recommendations for increasing uptake include utilizing Veteran peers, homeless service providers, and healthcare providers as trusted messengers to improve confidence in the vaccine.

COVID-19 vaccine hesitancy cannot fully explain disparities in vaccination coverage across the contiguous United States

Vaccine hesitancy has been identified as a major obstacle preventing comprehensive coverage against the COVID-19 pandemic. However, few studies have analyzed the association between ex-ante vaccine hesitancy and ex-post vaccination coverage. This study leveraged one-year county-level data across the contiguous United States to examine whether the prospective vaccine hesitancy eventually translates into differential vaccination rates, and whether vaccine hesitancy can explain socioeconomic, racial, and partisan disparities in vaccine uptake. A set of structural equation modeling was fitted with vaccine hesitancy and vaccination rate as endogenous variables, controlling for various potential confounders. The results demonstrated a significant negative link between vaccine hesitancy and vaccination rate, with the difference between the two continuously widening over time. Counties with higher socioeconomic statuses, more Asian and Hispanic populations, more elderly residents, greater health insurance coverage, and more Democrats presented lower vaccine hesitancy and higher vaccination rates. However, underlying determinants of vaccination coverage and vaccine hesitancy were divergent regarding their different associations with exogenous variables. Mediation analysis further demonstrated that indirect effects from exogenous variables to vaccination coverage via vaccine hesitancy only partially explained corresponding total effects, challenging the popular narrative that portrays vaccine hesitancy as a root cause of disparities in vaccination. Our study highlights the need of well-funded, targeted, and ongoing initiatives to reduce persisting vaccination inequities.