This Viewpoint enumerates the public health risks of involuntary displacement and offers 4 strategies that public health agencies can take to minimize the harms caused by dismantling homeless encampments. | eng

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 CDC is unwavering in our commitment to provide the highest quality laboratory diagnostic services for parasitic diseases. We clearly hear, understand, and concur with the concerns expressed in the accompanying editorial and appreciate the challenges the pause in testing for parasitic diseases presents for health-care providers, particularly those treating people at elevated risk for parasitic diseases. | | We also recognize the crucial role that our agency plays in ensuring those at risk receive equitable services for infections, including those that are generally known to all Americans as well as neglected diseases that are unfamiliar to most Americans. More broadly, the CDC works to protect the global community from parasitic diseases through three main priorities: reducing parasitic disease-related death, illness, and disability in the United States; reducing the global burden of malaria; and eliminating targeted neglected tropical diseases. Our Parasitic Diseases Laboratory is, in many ways, the foundation of this work and serves as a critical resource and often a laboratory of last resort for challenging diagnoses of unfamiliar pathogens when state and private laboratories do not have the relevant testing capacity. Our laboratory experts develop and improve tools and approaches to detect, prevent, and control disease; provide diagnostic assistance and expertise to public health laboratories; and conduct diagnostic tests for parasitic diseases.

In the United States, over 1.4 million people are estimated to access homeless services each year [1]. During their experience of homelessness, each of these people may face an increased risk of infectious diseases for several reasons. Homeless services are often provided in congregate facilities, and there may be little choice of with whom you spend time in close contact. Publicly available handwashing sinks can be difficult to locate and may be closed or lacking supplies. For people sleeping outside, bathrooms and showers can also be difficult to find on a regular basis. Additionally, many people experiencing homelessness have underlying medical conditions that can increase their risk of complications or substance use disorders that can put them at risk for drug-related infectious diseases [2].

Over a half million Americans experience homelessness on any given night and more than 1.4 million experience it at some point over the course of a year [1, 2]. Between 2016 and 2020, the number of people experiencing homelessness increased. The homelessness epidemic is intertwined with other epidemics, both infectious and noninfectious. For example, among US veterans who were diagnosed with opioid use disorder in 2012, 35% were experiencing homelessness. Rates of cardiovascular disease in people experiencing homelessness exceed those of the general population [3], and prevalence of invasive cancers have been reported to be significantly higher, with poorer overall cancer survival [4]. Among people with human immunodeficiency virus (HIV), 8.5% experienced homelessness in the last year, and those who experienced homelessness were 48% less likely to sustain viral suppression [5]. Invasive group A Streptococcus, invasive meningococcal disease, and Bartonella quintana infection have all been identified with much higher frequency among people experiencing homelessness than the general population [6, 7].

Homelessness is a serious public health issue. The number of people experiencing homelessness (PEH) has been increasing since 2016; on a single night in January 2020, an estimated 580 000 people were experiencing homelessness in the United States, more than 225 000 of whom were unsheltered (ie, having a primary nighttime location that is not designated as a regular sleeping accommodation, such as on the streets or in abandoned buildings, vehicles, or encampments). 1 Compared with the general US population, PEH experience elevated rates of infectious and noninfectious disease and face 3 to 10 times higher mortality rates.2,3 In the United States, non-Hispanic Black people were 3.5 times more likely than non-Hispanic White people to experience homelessness. 4 American Indian/Alaska Native people also have disproportionately high rates of homelessness compared with non-Hispanic White people. 5

Modeling complements surveillance data to inform COVID-19 public health decision making and policy development. This includes the use of modeling to improve situational awareness, to assess epidemiological characteristics, and to inform the evidence base for prevention strategies. To enhance modeling utility in future public health emergencies, the Centers for Disease Control and Prevention (CDC) launched the Infectious Disease Modeling and Analytics Initiative. The initiative objectives are to: (1) strengthen leadership in infectious disease modeling, epidemic forecasting, and advanced analytic work; (2) build and cultivate a community of skilled modeling and analytics practitioners and consumers across CDC; (3) strengthen and support internal and external applied modeling and analytic work; and, (4) working with partners, coordinate government-wide advanced data modeling and analytics for infectious diseases. These efforts are critical to help prepare CDC, the country, and the world to respond effectively to present and future infectious disease threats.

Homelessness is associated with a multitude of poor health outcomes. However, the full extent of the risks associated with homelessness are not possible to quantify without reliable population data. Here, we outline three federal, publicly-available data sources available to estimate the number of people experiencing homelessness in the United States. We describe the appropriate uses and limitations of each data source in the context of infectious disease epidemiology. These data sources provide an opportunity to expand current research and develop actionable analyses.

Prior to the coronavirus disease 2019 (COVID-19) pandemic, the efficacy of community mask wearing to reduce the spread of respiratory infections was controversial because there were no solid relevant data to support their use. During the pandemic, the scientific evidence has increased. Compelling data now demonstrate that community mask wearing is an effective nonpharmacologic intervention to reduce the spread of this infection, especially as source control to prevent spread from infected persons, but also as protection to reduce wearers’ exposure to infection.

IMPORTANCE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiology of coronavirus disease 2019 (COVID-19), is readily transmitted person to person. Optimal control of COVID-19 depends on directing resources and health messaging to mitigation efforts that are most likely to prevent transmission, but the relative importance of such measures has been disputed. OBJECTIVE: To assess the proportion of SARS-CoV-2 transmissions in the community that likely occur from persons without symptoms. DESIGN, SETTING, AND PARTICIPANTS: This decision analytical model assessed the relative amount of transmission from presymptomatic, never symptomatic, and symptomatic individuals across a range of scenarios in which the proportion of transmission from people who never develop symptoms (ie, remain asymptomatic) and the infectious period were varied according to published best estimates. For all estimates, data from a meta-analysis was used to set the incubation period at a median of 5 days. The infectious period duration was maintained at 10 days, and peak infectiousness was varied between 3 and 7 days (-2 and +2 days relative to the median incubation period). The overall proportion of SARS-CoV-2 was varied between 0% and 70% to assess a wide range of possible proportions. MAIN OUTCOMES AND MEASURES: Level of transmission of SARS-CoV-2 from presymptomatic, never symptomatic, and symptomatic individuals. RESULTS: The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms. CONCLUSIONS AND RELEVANCE: In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.

Over the past 2 decades, the United States (US) has experienced an unprecedented increase in overdose deaths as well as infectious disease consequences primarily associated with the misuse and injection of prescription opioid pain relievers and illicit opioids such as heroin and illicitly manufactured fentanyl. Indeed, injection drug use (IDU) and its myriad health impacts are a public health crisis, with an estimated 1 million people (0.24–0.59% of the noninstitutionalized population of the US) reporting IDU in the prior year (see Bradley in this supplement). Increases in IDU have led to outbreaks of human immunodeficiency virus (HIV) and higher rates of infections transmitted during nonsterile injection events, especially hepatitis C virus (HCV) and invasive bacteria and fungi that cause endocarditis, osteomyelitis, and skin and soft tissue infections [1–4]. In this supplement, “Infectious Diseases and Injection Drug Use: Public Health Burden and Response,” a number of authors (see names listed in parentheses throughout) highlight the changing environment for IDU-associated infections and the implications for surveillance, prevention, and control.

In this issue of JAMA, Wang et al present evidence that universal masking of health care workers (HCWs) and patients can help reduce transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections.1 In the largest health care system in Massachusetts with more than 75 000 employees, in tandem with routine symptom screening and diagnostic testing of symptomatic HCWs for SARS-CoV-2 infection, leadership mandated a policy of universal masking for all HCWs as well as for all patients. The authors present data that prior to implementation of universal masking in late March 2020, new infections among HCWs with direct or indirect patient contact were increasing exponentially, from 0% to 21.3% (a mean increase of 1.16% per day). However, after the universal masking policy was in place, the proportion of symptomatic HCWs with positive test results steadily declined, from 14.7% to 11.5% (a mean decrease of 0.49% per day). Although not a randomized clinical trial, this study provides critically important data to emphasize that masking helps prevent transmission of SARS-CoV-2.

In July 2015, personnel in the Alaska Division of Public Health's Section of Epidemiology became aware of an increase in the number of patients being treated in Anchorage hospital emergency departments for adverse reactions associated with use of synthetic cannabinoids (SCs). SCs are a chemically diverse class of designer drugs that bind to the same cannabinoid receptors as tetrahydrocannabinol, the main psychoactive component of cannabis. A public health investigation was initiated to describe clinical outcomes, characterize the outbreak, and identify SC chemicals circulating in Anchorage. During July 15, 2015-March 15, 2016, a total of 1,351 ambulance transports to Anchorage emergency departments for adverse SC reactions were identified. A review of charts obtained from two Anchorage hospitals determined that among 167 emergency department visits for adverse SC reactions during July 15-September 30, 2015, 11 (6.6%) involved a patient who required endotracheal intubation, 17 (10.2%) involved a patient who was admitted to the intensive care unit, and 66 (39.5%) involved a patient classified as being homeless. Testing of 25 product and paraphernalia samples collected from patients at one hospital identified 11 different SC chemicals. Educational outreach campaigns focused on the considerable health risks of using SCs need to complement judicial and law enforcement actions to reduce SC use.

OBJECTIVES: We compared pneumonia and influenza death rates among American Indian/Alaska Native (AI/AN) people with rates among Whites and examined geographic differences in pneumonia and influenza death rates for AI/AN persons. METHODS: We adjusted National Vital Statistics Surveillance mortality data for racial misclassification of AI/AN people through linkages with Indian Health Service (IHS) registration records. Pneumonia and influenza deaths were defined as those who died from 1990 through 1998 and 1999 through 2009 according to codes for pneumonia and influenza from the International Classification of Diseases, 9th and 10th Revision, respectively. We limited the analysis to IHS Contract Health Service Delivery Area counties, and compared pneumonia and influenza death rates between AI/ANs and Whites by calculating rate ratios for the 2 periods. RESULTS: Compared with Whites, the pneumonia and influenza death rate for AI/AN persons in both periods was significantly higher. AI/AN populations in the Alaska, Northern Plains, and Southwest regions had rates more than 2 times higher than those of Whites. The pneumonia and influenza death rate for AI/AN populations decreased from 39.6 in 1999 to 2003 to 33.9 in 2004 to 2009. CONCLUSIONS: Although progress has been made in reducing pneumonia and influenza mortality, disparities between AI/AN persons and Whites persist. Strategies to improve vaccination coverage and address risk factors that contribute to pneumonia and influenza mortality are needed.

In response to the 2009 H1N1 influenza pandemic, public health authorities launched an ambitious vaccination program to protect tens of millions of Americans from the virus. In April and May 2010, the Institute of Medicine Forum on Medical and Public Health Preparedness for Catastrophic Events hosted a series of 3 regional workshops to examine the 2009 H1N1 vaccination campaign. The workshops brought together stakeholders involved in distributing and dispensing H1N1 vaccine to discuss successes and challenges and to identify strategies to improve future vaccination programs and other medical countermeasure dispensing campaigns. On the basis of the presentations and the discussions that followed, several themes and opportunities for future efforts were identified in the following areas: vaccine supply and demand; state and local implementation of Centers for Disease Control and Prevention/Advisory Committee on Immunization Practices recommendations, including prioritization for vaccination; vaccine formulations and priority groups; opportunities for developing partnerships; opportunities to increase seasonal vaccination rates among pregnant women and health care workers and to increase acceptance of live attenuated nasal spray vaccine; standardization and improvement of immunization information management systems; opportunities to simplify, systematize, and automate processes and practices; and research needs and opportunities.

BACKGROUND: Foodborne botulism resulting from consumption of uncooked aquatic game foods has been an endemic hazard among Alaska Native populations for centuries. Our review was conducted to help target botulism prevention and response activities. METHODS: Records of Alaska botulism investigations for the period 1947-2007 were reviewed. We used the Centers for Disease Control and Prevention case definitions for foodborne botulism and linear regression to evaluate incidence trends and chi(2) or Fisher's Exact tests to evaluate categorical data. RESULTS: A total of 317 patients (61% of whom were female) and 159 outbreaks were reported. Overall mean annual incidence was 6.9 cases per 100,000 Alaska Native persons; mean incidence was lower in 2000 (5.7 cases per 100,000 Alaska Native persons) than in any period since 1965-1969 (0.8 cases per 100,000 Alaska Native persons). Age-specific incidence was highest (26.6 cases per 100,000 Alaska Native persons) among persons aged ≥60 years. The overall case-fatality rate was 8.2%, and the case-fatality rate was ≤4.0% since 1980. Misdiagnosis was associated with a higher case-fatality rate and delayed antitoxin administration. CONCLUSIONS: Foodborne botulism remains a public health problem in Alaska. Incidence might be decreasing, but it remains >800 times the overall US rate (0.0068 cases per 100,000 persons). Prevention messages should highlight the additional risk to female individuals and older persons. Early diagnosis is critical for timely access to antitoxin and supportive care. (See the editorial commentary by Austin, on pages 593-594.)

BACKGROUND: Older adults are at highest risk of invasive pneumococcal disease (IPD) and are recommended to receive vaccination with 23-valent pneumococcal polysaccharide vaccine (PPV23). Antibody concentrations decline following vaccination. We evaluated the immunogenicity and reactogenicity of revaccination and repeat revaccination. METHODS: Adults aged 55-74 years were vaccinated with a 1st to 4th dose of PPV23. Participants were eligible for revaccination if a minimum of 6 years had passed since their last dose of PPV23. Blood collected on the day of vaccination and 30 days later was analyzed by ELISA for IgG to five serotypes. Functional antibody activity was measured using an opsonophagocytic killing (OPK) assay. Reactions to vaccination were documented. RESULTS: Subjects were vaccinated with a 1st dose (n=123), 2nd dose (n=121), or 3rd or 4th dose (n=71) of PPV23. The post-vaccination IgG geometric mean concentrations (GMCs) were similar among first-time vaccinees and re-vaccinees for all serotypes with the exception of a lower GMC for serotype 1 in re-vaccinees. The post-vaccination OPK geometric mean titers (GMTs) were similar among first-time vaccinees and re-vaccinees with the exception of a higher GMT for serotype 6B in re-vaccinees. Compared to first-time vaccinees, re-vaccinees reported more joint pain (p=0.003), fatigue (p=0.027), headache (p=0.011), swelling (p=0.009), and moderate limitation in arm movement (p=0.015). CONCLUSIONS: Repeat revaccination with PPV23, administered 6 or more years after the prior dose, was immunogenic and generally well tolerated.

BACKGROUND: Vaccination with conjugate vaccines stimulates T cell-dependent immunity, whereas vaccination with polysaccharide vaccines does not. Thus, vaccination with the 7-valent pneumococcal conjugate vaccine (PCV7) followed by the 23-valent pneumococcal polysaccharide vaccine (PPV23) may offer better protection against invasive pneumococcal disease for older adults than does vaccination with PPV23 alone, which is what is currently recommended. METHODS: Alaska Native adults 55-70 years of age with no previous pneumococcal vaccination were randomized to receive (1) PPV23, (2) PCV7 followed 2 months later by PPV23, or (3) PCV7 followed 6 months later by PPV23. Participants recorded reactions after each vaccination. Serum samples collected during the period from May 2002 through February 2003 were tested for serotype-specific immunoglobulin G (IgG) and for opsonophagocytic activity (OPA) against serotypes 1, 4, 6B, 14, and 19F. RESULTS: Vaccination with PCV7 was well tolerated, but persons receiving PCV7 followed by PPV23 reported more local reactions than those receiving only PPV23. All reactions resolved spontaneously within 72 h of receiving vaccine. The geometric mean IgG concentrations of and the median OPA titers to serotypes 4, 6B, 14, and 19F increased in all groups after 1 dose of either PCV7 or PPV23. Serotype-specific geometric mean IgG concentrations and median OPA titers did not differ between any of the groups after vaccination with PPV23, regardless of whether they had previously received PCV7. CONCLUSIONS: In this study, PCV7 given 2 or 6 months before PPV23 was well tolerated but did not improve immune response to PPV23 in older Alaska Native adults.