Peter J. Davidson

Bio: Peter J. Davidson is an academic researcher from University of California, San Diego. The author has contributed to research in topics: Opioid overdose & Population. The author has an hindex of 30, co-authored 81 publications receiving 3571 citations. Previous affiliations of Peter J. Davidson include Christchurch Hospital & University of California, San Francisco.

Opioid Overdose Prevention Programs Providing Naloxone to Laypersons - United States, 2014.

Abstract: Drug overdose deaths in the United States have more than doubled since 1999. During 2013, 43,982 drug overdose deaths (unintentional, intentional [suicide or homicide], or undetermined intent) were reported. Among these, 16,235 (37%) were associated with prescription opioid analgesics (e.g., oxycodone and hydrocodone) and 8,257 (19%) with heroin. For many years, community-based programs have offered opioid overdose prevention services to laypersons who might witness an overdose, including persons who use drugs, their families and friends, and service providers. Since 1996, an increasing number of programs provide laypersons with training and kits containing the opioid antagonist naloxone hydrochloride (naloxone) to reverse the potentially fatal respiratory depression caused by heroin and other opioids. In July 2014, the Harm Reduction Coalition (HRC), a national advocacy and capacity-building organization, surveyed 140 managers of organizations in the United States known to provide naloxone kits to laypersons. Managers at 136 organizations completed the survey, reporting on the amount of naloxone distributed, overdose reversals by bystanders, and other program data for 644 sites that were providing naloxone kits to laypersons as of June 2014. From 1996 through June 2014, surveyed organizations provided naloxone kits to 152,283 laypersons and received reports of 26,463 overdose reversals. Providing opioid overdose training and naloxone kits to laypersons who might witness an opioid overdose can help reduce opioid overdose mortality.

Gender differences in sexual and injection risk behavior among active young injection drug users in San Francisco (the UFO Study).

Abstract: Female injection drug users (IDUs) represent a large proportion of persons infected with HIV in the United States, and women who inject drugs have a high incidence of hepatitis B virus (HBV) and hepatitis C virus (HCV) injection. Therefore, it is important to understand the role of gender in injection risk behavior and the transmission of blood-borne virus. In 2000–2002, 844 young (<30 years old) IDUs were surveyed in San Francisco. We compared self-reported risk behavior between 584 males and 260 female participants from cross-sectional baseline data. We used logistic regression to determine whether demographic, structural, and relationship variables explained increased needle borrowing, drug preparation equipment sharing, and being injected by another IDU among females compared to males. Females were significantly younger than males and were more likely to engage in needle borrowing, ancillary equipment sharing, and being injected by someone else. Females were more likely than males to report recent sexual intercourse and to have IDU sex partners. Females and males were not different with respect to education, race/ethnicity, or housing status. In logistic regression models for borrowing a used needle and sharing drug preparation equipment, increased risk in females was explained by having an injection partner who was also a sexual partner. Injecting risk was greater in the young female compared to male IDUs despite equivalent frequency of injecting. Overlapping sexual and injection partnerships were a key factor in explaining increased injection risk in females. Females were more likely to be injected by another IDU even after adjusting for years injecting, being in a relationship with another IDU, and other potential confounders. Interventions to reduce sexual and injection practices that put women at risk of contracting hepatitis and HIV are needed.

Community-Based Opioid Overdose Prevention Programs Providing Naloxone — United States, 2010

Abstract: Drug overdose death rates have increased steadily in the United States since 1979. In 2008, a total of 36,450 drug overdose deaths (i.e., unintentional, intentional [suicide or homicide], or undetermined intent) were reported, with prescription opioid analgesics (e.g., oxycodone, hydrocodone, and methadone), cocaine, and heroin the drugs most commonly involved (1). Since the mid-1990s, community-based programs have offered opioid overdose prevention services to persons who use drugs, their families and friends, and service providers. Since 1996, an increasing number of these programs have provided the opioid antagonist naloxone hydrochloride, the treatment of choice to reverse the potentially fatal respiratory depression caused by overdose of heroin and other opioids (2). Naloxone has no effect on non-opioid overdoses (e.g., cocaine, benzodiazepines, or alcohol) (3). In October 2010, the Harm Reduction Coalition, a national advocacy and capacity-building organization, surveyed 50 programs known to distribute naloxone in the United States, to collect data on local program locations, naloxone distribution, and overdose reversals. This report summarizes the findings for the 48 programs that completed the survey and the 188 local programs represented by the responses. Since the first opioid overdose prevention program began distributing naloxone in 1996, the respondent programs reported training and distributing naloxone to 53,032 persons and receiving reports of 10,171 overdose reversals. Providing opioid overdose education and naloxone to persons who use drugs and to persons who might be present at an opioid overdose can help reduce opioid overdose mortality, a rapidly growing public health concern. Overdose is common among persons who use opioids, including heroin users. In a 2002–2004 study of 329 drug users, 82% said they had used heroin, 64.6% had witnessed a drug overdose, and 34.6% had experienced an unintentional drug overdose (4). In 1996, community-based programs began offering naloxone and other opioid overdose prevention services to persons who use drugs, their families and friends, and service providers (e.g., health-care providers, homeless shelters, and substance abuse treatment programs). These services include education regarding overdose risk factors, recognition of signs of opioid overdose, appropriate responses to an overdose, and administration of naloxone. To identify local program locations and assess the extent of naloxone distribution, in October 2010 the Harm Reduction Coalition e-mailed an online survey to staff members at the 50 programs then known to distribute naloxone. Follow-up e-mails and telephone calls were used to encourage participation, clarify responses, and obtain information on local, community-based programs. The survey included questions about the year the program began distributing naloxone, the number of persons trained in overdose prevention and naloxone administration, the number of overdose reversals reported, and whether the totals were estimates or based on program data. The survey also asked questions regarding the naloxone formulations currently distributed, any recent difficulties in obtaining naloxone, and the program’s experience with naloxone distribution. Staff members at 48 (96%) of the 50 programs completed the online survey. Since the first program began distributing naloxone in 1996, through June 2010, the 48 responding programs reported providing training and distributing naloxone to an estimated 53,032 persons (program range: zero to 16,220; median: 102.5; mean: 1,104.8).* From the first naloxone distribution in 1996 through June 2010, the programs received reports of 10,171 overdose reversals using naloxone (range: zero to 2,385; median: 32; mean: 211.9).† During a recent 12-month period, respondents distributed an estimated 38,860 naloxone vials (Table).§ Using data from the survey, the number of programs beginning naloxone distribution each year during 1996–2010 was compared with the annual crude rates of unintentional drug overdose deaths per 100,000 population from 1979 to 2008 (Figure 1) (1). FIGURE 1 Annual crude rates* of unintentional drug overdose deaths and number of overdose prevention programs distributing naloxone — United States, 1979–2010 TABLE Number of opioid overdose programs/local programs, naloxone vials provided in a recent 12-month period, program participants overall, and overdose reversals, by program size — United States, 1996–2010 The 48 responding programs were located in 15 states and the District of Columbia. Four responding programs provided consolidated data for multiple local, community-based programs. Three state health departments, in New York, New Mexico, and Massachusetts, provided data for 129 local programs (65, 56, and eight, respectively); a nongovernmental organization in Wisconsin provided data on a statewide operation with 16 local programs. In all, the 48 responding programs provided data for 188 local opioid overdose prevention programs that distributed naloxone (Figure 2). Nineteen (76.0%) of the 25 states with 2008 drug overdose death rates higher than the median and nine (69.2%) of the 13 states in the highest quartile (1) did not have a community-based opioid overdose prevention program that distributed naloxone (Figure 2). FIGURE 2 Number (N = 188) and location* of local drug overdose prevention programs providing naloxone in 2010 and age-adjusted rates† of drug overdose deaths§ in 2008 — United States For a recent 12-month period, the 48 responding programs reported distributing 38,860 naloxone vials, including refills (range: zero to 12,070; median: 97; mean: 809.6).¶ Overdose prevention programs were characterized as small, medium, large, or very large, based on the number of naloxone vials distributed during that period. The six responding programs in the large and very large categories distributed 32,812 (84.4%) of the naloxone vials (Table). Twenty-one (43.7%) responding programs reported problems obtaining naloxone in the “past few months” before the survey. The most frequently reported reasons for difficulties obtaining naloxone were the cost of naloxone relative to available funding and the inability of suppliers to fill orders.**

Structural violence and structural vulnerability within the risk environment: Theoretical and methodological perspectives for a social epidemiology of HIV risk among injection drug users and sex workers

Abstract: The transmission of HIV is shaped by individual-environment inter­actions. Social epidemiologic approaches thus seek to capture the dynamic and reciprocal relationships of individual-environment interactions in the production and reduction of risk. This presents considerable methodological, theoretical and disciplinary challenges. Drawing upon four research case studies, we consider how methods and concepts in the social and epidemiologic sciences might be brought together towards understanding HIV risk as an effect of social, cultural and political condition. The case studies draw upon different combinations of methods (qualitative, ethnographic and quantitative) and disciplines (sociology, anthropology and epidemiology) in different social contexts of HIV vulnerability (street settings in Russia, Serbia and North America and a cross-border setting in Mexico) among a range of marginalised high-risk populations (injection drug users and female and transvestite sex workers). These case studies illustrate the relevance of the social science concepts of “structural violence” and “structural vulnerability” for a social epidemiology of HIV risk. They also explore how social epidemiologic work can benefit from the mixing of social science methods and theories. We contend that social epidemiology cannot advance in its understanding of structural vulnerability without embracing and relying upon ethnographic and qualitative approaches. We put ­forward the linked concepts of “structural violence,” “structural vulnerability” and “risk environment” as building blocks for a theory-informed social epidemiology of HIV risk among marginalised populations.

Immunosuppressive networks in the tumour environment and their therapeutic relevance

Abstract: It is well known that many tumours are potentially immunogenic, as corroborated by the presence of tumour-specific immune responses in vivo. Nonetheless, spontaneous clearance of established tumours by endogenous immune mechanisms is rare. Therefore, the focus of most cancer immunotherapies is to supplement essential immunogenic elements to boost tumour-specific immunity. Why then has tumour immunotherapy resulted in a generally poor clinical efficiency? The reason might lie in the increasingly documented fact that tumours develop diverse strategies that escape tumour-specific immunity.

Immunosuppressive Strategies that are Mediated by Tumor Cells

Abstract: Despite major advances in understanding the mechanisms leading to tumor immunity, a number of obstacles hinder the successful translation of mechanistic insights into effective tumor immunotherapy. Such obstacles include the ability of tumors to foster a tolerant microenvironment and the activation of a plethora of immunosuppressive mechanisms, which may act in concert to counteract effective immune responses. Here we discuss different strategies employed by tumors to thwart immune responses, including tumor-induced impairment of antigen presentation, the activation of negative costimulatory signals, and the elaboration of immunosuppressive factors. In addition, we underscore the influence of regulatory cell populations that may contribute to this immunosuppressive network; these include regulatory T cells, natural killer T cells, and distinct subsets of immature and mature dendritic cells. The current wealth of preclinical information promises a future scenario in which the synchronized blockade of immunosuppressive mechanisms may be effective in combination with other conventional strategies to overcome immunological tolerance and promote tumor regression.