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.

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.

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.

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.

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.

Immunogenicity and reactogenicity of pneumococcal polysaccharide and conjugate vaccines in alaska native adults 55-70 years of age.

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.

Trends in nephropathy among HIV-infected patients.

BACKGROUND: Nephropathy complicates the course and adversely impacts on the prognosis of HIV-infected patients. We examined trends and correlates of all-cause nephropathy (ACN). METHODS: Correlates of and trends in ACN were examined in the entire Adult/Adolescent Spectrum of HIV Disease longitudinal observational cohort. Patients were enrolled and followed in the cohort for a median period of 3 years between January 1990 and December 2003 in 11 US metropolitan areas. RESULTS: The incidence of ACN rose among HIV-infected individuals through the mid-1990s, then declined. The proportion of patients with ACN at the time of death increased over the study period. Black race, injection-drug use (IDU), indinavir, hypertension, diabetes, decreased CD4+ lymphocyte count, increased viral load, and increased age were all highly associated with ACN. DISCUSSION: Nephropathy represents an important health disparity impacting HIV-infected blacks and IDU with implications for mortality.

Invasive pneumococcal disease caused by nonvaccine serotypes among alaska native children with high levels of 7-valent pneumococcal conjugate vaccine coverage.

CONTEXT: With routine childhood vaccination using heptavalent pneumococcal conjugate vaccine, one concern has been the potential for emergence and expansion of replacement disease caused by serotypes not contained in the heptavalent conjugate vaccine. OBJECTIVE: To determine whether replacement disease is associated with the overall decline in invasive pneumococcal disease among Alaska Native children. DESIGN, SETTING, AND PATIENTS: Alaska statewide longitudinal population-based laboratory surveillance of invasive Streptococcus pneumoniae infections from January 1, 1995, through December 31, 2006. MAIN OUTCOME MEASURES: Incidence and types of pneumococcal disease in children younger than 2 years. RESULTS: In the first 3 years after introduction of routine vaccination with heptavalent pneumococcal conjugate vaccine, overall invasive pneumococcal disease decreased 67% in Alaska Native children younger than 2 years (from 403.2 per 100,000 in 1995-2000 to 134.3 per 100,000 per year in 2001-2003, P<.001). However, between 2001-2003 and 2004-2006, there was an 82% increase in invasive disease in Alaska Native children younger than 2 years to 244.6/100,000 (P = .02). Since 2004, the invasive pneumococcal disease rate caused by nonvaccine serotypes has increased 140% compared with the prevaccine period (from 95.1 per 100,000 in 1995-2000 to 228.6 in 2004-2006, P = .001). During the same period, there was a 96% decrease in heptavalent vaccine serotype disease. Serotype 19A accounted for 28.3% of invasive pneumococcal disease among Alaska children younger than 2 years during 2004-2006. There was no significant increase in nonvaccine disease in non-Native Alaska children younger than 2 years. CONCLUSIONS: Alaska Native children are experiencing replacement invasive pneumococcal disease with serotypes not covered by heptavalent pneumococcal conjugate vaccine. The demonstration of replacement invasive pneumococcal disease emphasizes the importance of ongoing surveillance and development of expanded valency vaccines.

Decline in respiratory syncytial virus hospitalizations in a region with high hospitalization rates and prolonged season.

BACKGROUND: During 1993 to 1996, Alaska Native infants <1 year of age from the Yukon Kuskokwim (YK) Delta in Alaska experienced a respiratory syncytial virus (RSV) hospitalization rate 5 times the U.S. general infant population rate. We describe trends in lower respiratory tract infection (LRTI) and RSV hospitalizations in YK children from 1994 to 2004. METHODS: We abstracted hospital dates, RSV test results and clinical information from the hospital records for YK children <3 years of age hospitalized between July 1994 and June 2004. RESULTS: : The RSV hospitalization rate in YK Delta children <1 year of age decreased from 178 per 1000 infants per year (1994-1997) to 104 per 1000 infants per year (2001-2004) (P < 0.001), and the RSV hospitalization rate for premature infants decreased from 317 to 123 per 1000 infants per year (P < 0.001). The risk reduction for RSV hospitalization was greater in premature (relative risk, 0.39) than in term infants (relative risk, 0.60; P = 0.04). The rate of non-RSV LRTI hospitalizations increased from 153 to 215 per 1000 infants per year (P < 0.001). The median RSV season length was 30.5 weeks. Pneumonia was diagnosed in more than half of RSV admissions. CONCLUSIONS: In YK infants, the RSV hospitalization rate decreased by one-third between 1994 and 2004; however, the overall LRTI hospitalization rate did not change. The median RSV season was twice as long as for the U.S. population. Palivizumab prophylaxis may be responsible for the larger decrease in the RSV hospitalization rate among premature infants; however, the 2001-2004 RSV hospitalization rate among YK infants remained 3 times higher than the U.S. infant rate.