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.

Improving Pandemic Response: Employing Mathematical Modeling to Confront Coronavirus Disease 2019.

Modeling complements surveillance data to inform coronavirus disease 2019 (COVID-19) public health decision making and policy development. This includes the use of modeling to improve situational awareness, assess epidemiological characteristics, and 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 the CDC, the country, and the world to respond effectively to present and future infectious disease threats.

Data Sources That Enumerate People Experiencing Homelessness in the United States: Opportunities and Challenges for Epidemiologic Research.

Homelessness is associated with a multitude of poor health outcomes. However, the full extent of the risks associated with homelessness is not possible to quantify without reliable population data. Here, we outline 3 federal, publicly available data sources for estimating 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.

SARS-CoV-2 Transmission From People Without COVID-19 Symptoms.

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.

Increase in Adverse Reactions Associated with Use of Synthetic Cannabinoids - Anchorage, Alaska, 2015-2016.

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.

Pneumonia and influenza mortality among American Indian and Alaska Native people, 1990-2009.

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.

Estimating the burden of pneumococcal pneumonia among adults: a systematic review and meta-analysis of diagnostic techniques.

BACKGROUND: Pneumococcal pneumonia causes significant morbidity and mortality among adults. Given limitations of diagnostic tests for non-bacteremic pneumococcal pneumonia, most studies report the incidence of bacteremic or invasive pneumococcal disease (IPD), and thus, grossly underestimate the pneumococcal pneumonia burden. We aimed to develop a conceptual and quantitative strategy to estimate the non-bacteremic disease burden among adults with community-acquired pneumonia (CAP) using systematic study methods and the availability of a urine antigen assay. METHODS AND FINDINGS: We performed a systematic literature review of studies providing information on the relative yield of various diagnostic assays (BinaxNOW® S. pneumoniae urine antigen test (UAT) with blood and/or sputum culture) in diagnosing pneumococcal pneumonia. We estimated the proportion of pneumococcal pneumonia that is bacteremic, the proportion of CAP attributable to pneumococcus, and the additional contribution of the Binax UAT beyond conventional diagnostic techniques, using random effects meta-analytic methods and bootstrapping. We included 35 studies in the analysis, predominantly from developed countries. The estimated proportion of pneumococcal pneumonia that is bacteremic was 24.8% (95% CI: 21.3%, 28.9%). The estimated proportion of CAP attributable to pneumococcus was 27.3% (95% CI: 23.9%, 31.1%). The Binax UAT diagnosed an additional 11.4% (95% CI: 9.6, 13.6%) of CAP beyond conventional techniques. We were limited by the fact that not all patients underwent all diagnostic tests and by the sensitivity and specificity of the diagnostic tests themselves. We address these resulting biases and provide a range of plausible values in order to estimate the burden of pneumococcal pneumonia among adults. CONCLUSIONS: Estimating the adult burden of pneumococcal disease from bacteremic pneumococcal pneumonia data alone significantly underestimates the true burden of disease in adults. For every case of bacteremic pneumococcal pneumonia, we estimate that there are at least 3 additional cases of non-bacteremic pneumococcal pneumonia.

The Institute of Medicine's Forum on Medical and Public Health Preparedness for Catastrophic Events: regional workshop series on the 2009 H1N1 influenza vaccination campaign.

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.

Endemic foodborne botulism among Alaska Native persons--Alaska, 1947-2007.

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 χ(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.

Repeat revaccination with 23-valent pneumococcal polysaccharide vaccine among adults aged 55-74 years living in Alaska: no evidence of hyporesponsiveness.

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=0.004), fatigue (p=0.019), headache (p=0.014), swelling (p=0.006), and moderate limitation in arm movement (p=0.025). CONCLUSIONS: Repeat revaccination with PPV23, administered 6 or more years after the prior dose, was immunogenic and generally well tolerated.