Quantifying heterogeneities in arbovirus transmission: Description of the rationale and methodology for a prospective longitudinal study of dengue and Zika virus transmission in Iquitos, Peru (2014-2019).

Current knowledge of dengue virus (DENV) transmission provides only a partial understanding of a complex and dynamic system yielding a public health track record that has more failures than successes. An important part of the problem is that the foundation for contemporary interventions includes a series of longstanding, but untested, assumptions based on a relatively small portion of the human population; i.e., people who are convenient to study because they manifest clinically apparent disease. Approaching dengue from the perspective of people with overt illness has produced an extensive body of useful literature. It has not, however, fully embraced heterogeneities in virus transmission dynamics that are increasingly recognized as key information still missing in the struggle to control the most important insect-transmitted viral infection of humans. Only in the last 20 years have there been significant efforts to carry out comprehensive longitudinal dengue studies. This manuscript provides the rationale and comprehensive, integrated description of the methodology for a five-year longitudinal cohort study based in the tropical city of Iquitos, in the heart of the Peruvian Amazon. Primary data collection for this study was completed in 2019. Although some manuscripts have been published to date, our principal objective here is to support subsequent publications by describing in detail the structure, methodology, and significance of a specific research program. Our project was designed to study people across the entire continuum of disease, with the ultimate goal of quantifying heterogeneities in human variables that affect DENV transmission dynamics and prevention. Because our study design is applicable to other Aedes transmitted viruses, we used it to gain insights into Zika virus (ZIKV) transmission when during the project period ZIKV was introduced and circulated in Iquitos. Our prospective contact cluster investigation design was initiated by detecttion of a person with a symptomatic DENV infection and then followed that person's immediate contacts. This allowed us to monitor individuals at high risk of DENV infection, including people with clinically inapparent and mild infections that are otherwise difficult to detect. We aimed to fill knowledge gaps by defining the contribution to DENV transmission dynamics of (1) the understudied majority of DENV-infected people with inapparent and mild infections and (2) epidemiological, entomological, and socio-behavioral sources of heterogeneity. By accounting for factors underlying variation in each person's contribution to transmission we sought to better determine the type and extent of effort needed to better prevent virus transmission and disease.

Exploring perceived risk for COVID-19 and its role in protective behavior and COVID-19 vaccine hesitancy: a qualitative study after the first wave.

BACKGROUND: The novel coronavirus pandemic (COVID-19) has had severe impacts on morbidity and mortality globally. METHODS: This study was set in rural central Kentucky and included participants recruited from public spaces. Fifteen qualitative interviews about personal experiences during the COVID-19 pandemic were conducted by phone from July 3 to July 24, 2020. Interviews were recorded, transcribed, and coded using a grounded theory approach. RESULTS: Participants who perceived COVID-19 to be a severe risk tended to have personal health concerns and therefore reported taking protective measures for themselves. A slightly smaller proportion of participants reported taking measures to protect others (particularly family). A minority of participants had an ambivalent attitude towards the risk and only took measures if required. COVID-19 vaccine acceptability was low with most participants expressing concerns regarding their need for a vaccine, safety of this vaccine, the value of personal rights, or future vaccine supply. CONCLUSIONS: Most participants perceived some risk of COVID-19 and took steps to prevent infections in themselves and others. Mandates for mask use in certain locations were additionally useful for those who had an ambivalent attitude towards the risk of illness. There was surprisingly little connection between perceiving COVID-19 risk and a desire for the COVID-19 vaccine. In this setting, vaccine acceptability was low, with vaccine concerns outweighing perceived potential benefits. In conclusion, because the risk was often constructed in terms of worries for themselves and others, the framing of health education materials for protective behaviors in these terms may be effective. Furthermore, future COVID-19 vaccine education should address vaccine knowledge and concerns, such as the need for a vaccine and its safety, and emphasize how a vaccination would reduce their chances of severe disease if they were to get sick.