Determining seropositivity-A review of approaches to define population seroprevalence when using multiplex bead assays to assess burden of tropical diseases.

BACKGROUND: Serological surveys with multiplex bead assays can be used to assess seroprevalence to multiple pathogens simultaneously. However, multiple methods have been used to generate cut-off values for seropositivity and these may lead to inconsistent interpretation of results. A literature review was conducted to describe the methods used to determine cut-off values for data generated by multiplex bead assays. METHODOLOGY/PRINCIPAL FINDINGS: A search was conducted in PubMed that included articles published from January 2010 to January 2020, and 308 relevant articles were identified that included the terms "serology", "cut-offs", and "multiplex bead assays". After application of exclusion of articles not relevant to neglected tropical diseases (NTD), vaccine preventable diseases (VPD), or malaria, 55 articles were examined based on their relevance to NTD or VPD. The most frequently applied approaches to determine seropositivity included the use of presumed unexposed populations, mixture models, receiver operating curves (ROC), and international standards. Other methods included the use of quantiles, pre-exposed endemic cohorts, and visual inflection points. CONCLUSIONS/SIGNIFICANCE: For disease control programmes, seropositivity is a practical and easily interpretable health metric but determining appropriate cut-offs for positivity can be challenging. Considerations for optimal cut-off approaches should include factors such as methods recommended by previous research, transmission dynamics, and the immunological backgrounds of the population. In the absence of international standards for estimating seropositivity in a population, the use of consistent methods that align with individual disease epidemiological data will improve comparability between settings and enable the assessment of changes over time.

Challenges of Managing Skin Diseases in Refugees and Migrants.

"Currently, an estimated 70.8 million individuals worldwide are forcibly displaced due to war, violence, and persecution. Barriers to providing dermatologic care include the large number of affected people, their movement within and across international borders, security issues, and limited access to dermatology expertise and formularies. Screening protocols for skin diseases and sexually transmitted infections differ worldwide, raising the need for shared guidelines to assess migrants' health. This article reviews the literature of skin and sexually transmitted infections in migrants and displaced persons, highlighting the impact of social determinants on skin health and challenges faced in providing care."

Recognizing Vaccine-Preventable Diseases and Managing Outbreaks.

Outbreaks of vaccine-preventable diseases are becoming more common in the United States. Outbreaks of some diseases, such as measles, can be attributed to decreasing vaccination rates. Clinicians need to be aware of the vulnerabilities in their communities. Detection of an outbreak requires familiarity with signs, symptoms, and laboratory findings for these now unusual diseases. Clinicians also need to work with public health officials to identify, treat, and limit the spread of these infections. This article describes the populations most at risk from illnesses associated with sporadic outbreaks, with information on diagnosis, treatment, and ways to limit the spread of infection.

Resurgence of Vaccine-Preventable Disease: Ethics in the Pediatric Emergency Department.

After a decades-long reduction in vaccine-preventable illnesses worldwide, there has been a reappearance of childhood illnesses once thought to be eradicated. This resurgence in illnesses such as polio and measles is a consequence of multifactorial events leading to decreased vaccination rates. A lack of resources in poor and war-torn countries, coupled with increasing global travel, and decisions to delay or defer vaccinations because of inaccurate studies further emphasized by media have combined to result in current state of frequent local and widespread epidemics, specifically the current outbreak of measles. As providers in the pediatric emergency department, we are often the first to encounter children manifesting these diseases. It is imperative that we understand the circumstances leading to these encounters, so that we can have engaged conversations with families, gain an understanding of their motivations, dispel any misinformed beliefs, and encourage positive health behaviors for their children.

Resurgence of Vaccine-Preventable Diseases in Venezuela as a Regional Public Health Threat in the Americas.

Venezuela's tumbling economy and authoritarian rule have precipitated an unprecedented humanitarian crisis. Hyperinflation rates now exceed 45,000%, and Venezuela's health system is in free fall. The country is experiencing a massive exodus of biomedical scientists and qualified healthcare professionals. Reemergence of arthropod-borne and vaccine-preventable diseases has sparked serious epidemics that also affect neighboring countries. In this article, we discuss the ongoing epidemics of measles and diphtheria in Venezuela and their disproportionate impact on indigenous populations. We also discuss the potential for reemergence of poliomyelitis and conclude that action to halt the spread of vaccine-preventable diseases within Venezuela is a matter of urgency for the country and the region. We further provide specific recommendations for addressing this crisis.