SARS-CoV-2 infections in households in a peri-urban community of Lima, Peru: A prospective cohort study

Investigating SARS-CoV-2 Incidence and Morbidity in Ponce, Puerto Rico: Protocol and Baseline Results From a Community Cohort Study

BACKGROUND

A better understanding of SARS-CoV-2 infection risk among Hispanic and Latino populations and in low-resource settings in the United States is needed to inform control efforts and strategies to improve health equity. Puerto Rico has a high poverty rate and other population characteristics associated with increased vulnerability to COVID-19, and there are limited data to date to determine community incidence.

OBJECTIVE

This study describes the protocol and baseline seroprevalence of SARS-CoV-2 in a prospective community-based cohort study (COPA COVID-19 [COCOVID] study) to investigate SARS-CoV-2 infection incidence and morbidity in Ponce, Puerto Rico.

METHODS

In June 2020, we implemented the COCOVID study within the Communities Organized to Prevent Arboviruses project platform among residents of 15 communities in Ponce, Puerto Rico, aged 1 year or older. Weekly, participants answered questionnaires on acute symptoms and preventive behaviors and provided anterior nasal swab samples for SARS-CoV-2 polymerase chain reaction testing; additional anterior nasal swabs were collected for expedited polymerase chain reaction testing from participants that reported 1 or more COVID-19-like symptoms. At enrollment and every 6 months during follow-up, participants answered more comprehensive questionnaires and provided venous blood samples for multiantigen SARS-CoV-2 immunoglobulin G antibody testing (an indicator of seroprevalence). Weekly follow-up activities concluded in April 2022 and 6-month follow-up visits concluded in August 2022. Primary study outcome measures include SARS-CoV-2 infection incidence and seroprevalence, relative risk of SARS-CoV-2 infection by participant characteristics, SARS-CoV-2 household attack rate, and COVID-19 illness characteristics and outcomes. In this study, we describe the characteristics of COCOVID participants overall and by SARS-CoV-2 seroprevalence status at baseline.

RESULTS

We enrolled a total of 1030 participants from 388 households. Relative to the general populations of Ponce and Puerto Rico, our cohort overrepresented middle-income households, employed and middle-aged adults, and older children (P<.001). Almost all participants (1021/1025, 99.61%) identified as Latino/a, 17.07% (175/1025) had annual household incomes less than US $10,000, and 45.66% (463/1014) reported 1 or more chronic medical conditions. Baseline SARS-CoV-2 seroprevalence was low (16/1030, 1.55%) overall and increased significantly with later study enrollment time (P=.003).

CONCLUSIONS

The COCOVID study will provide a valuable opportunity to better estimate the burden of SARS-CoV-2 and associated risk factors in a primarily Hispanic or Latino population, assess the limitations of surveillance, and inform mitigation measures in Puerto Rico and other similar populations.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/53837.

The dynamics and determinants of specific systemic and mucosal antibody responses to SARS-CoV-2 in three adult cohorts in the Ecuadorian Andes: a study protocol

Introduction

There are limited longitudinal data on the systemic and mucosal antibody responses to SARS-CoV-2 from Latin America, a region severely affected by COVID-19, and where vaccine strategies have been implemented during the evolving pandemic.

Objective

To evaluate determinants of seroprevalence and changes in levels of anti-SARS-CoV-2 antibodies longitudinally in adults with different levels of exposure to SARS-CoV-2 (defined a priori as low, medium, and high based on presumed occupational risk), in two Andean cities in Ecuador.

Methods

Longitudinal cohort study of 1,000 adults aged 18 years and older with questionnaire data and sample collection done at 0, 3, 6, and 12 months during the period 2020-2023. Observations collected included WHO-ISARIC questionnaire and peripheral blood and saliva samples for measurement of IgG and IgA antibodies, respectively. Planned analyses are tailored to the longitudinal nature of the outcomes defined by participants' antibody levels and aim at estimating their average trends with time since infection in each of the occupational groups, adjusted for demographics and calendar-time levels of SARS-CoV-2 infection in the general population. The latter reflect the impact of the national control measures such as vaccinations and movement restrictions.

Importance

Understanding the duration and the dynamics of waning immunity to SARS-CoV-2, in the context of exposures to emerging virus variants and immunization, will inform the implementation of targeted public health strategies in the Latin American region.

Ethics and Dissemination

This study will observe the bioethical principles of the Declaration of Helsinki. Informed written consent will be obtained. Samples from participants will be stored for up to three years after which they will be destroyed. The study protocol was approved by the Ecuadorian Ministry of Public Health Ethics Committee for COVID-19 Research. Antibody results will be provided to participants and participating institutions and to the national health authorities.

SARS-CoV-2 self-testing in Peru: a cross-sectional survey of values and attitudes of the general population

OBJECTIVES

To assess the values of and attitudes towards the use of rapid SARS-CoV-2 antigen-detection tests for self-testing in a rural and an urban area in Peru.

DESIGN

Cross-sectional, street-based population survey.

SETTING

A series of over 400 randomly selected street points in Valle del Mantaro and in Lima.

PARTICIPANTS

438 respondents (203 female) participated. They were all older than 17 years and provided informed consent for participation.

INTERVENTION

All respondents answered on the spot, a 35-item questionnaire developed in KoboToolbox.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes of interest were: likelihood to use a SARS-CoV-2 self-test; willingness to pay for a SARS-CoV-2 self-test and likelihood to comply with recommended actions following a positive SARS-CoV-2 self-test result. Bivariate analyses and Poisson regression (PR) analyses were performed to identify significant associations between dependent variables and independent variables pertaining to respondents' characteristics, risk perception and previous experiences with conventional COVID-19 testing.

RESULTS

Of the 438 respondents, 51.49% had previous experience with conventional COVID-19 testing; 20.37% had COVID-19 disease; 86.96% accepted the idea of SARS-CoV-2 self-testing; and, 78.95% would be likely to use it if needed. Almost all (94.75%) would pay for a self-testing device (mean acceptable payment: US$10.4) if it was not provided free of charge by health authorities. Overall, 93.12%, 86.93% and 85.32% would self-isolate, report the results and warn their contacts, respectively. Being a female (adjusted PR 1.05, 95% CI 1.00 to 1.09, p<0.018), having completed secondary education (adjusted PR 1.18, 95% CI 1.02 to 1.37, p<0.024) and expressing likelihood to use self-testing (adjusted PR 1.08, 95% CI 1.01 to 1.16, p<0.0.24) could be predictors of willingness to pay for a self-test.

CONCLUSIONS

Self-testing is perceived as an acceptable approach. Health authorities in Peru should facilitate access to this approach to complement healthcare facilities-led testing efforts for COVID-19. Future research is necessary to understand the impact of self-testing in case detection and pandemic control.

Saliva as a sample type for SARS-CoV-2 detection: implementation successes and opportunities around the globe

INTRODUCTION

Symptomatic testing and asymptomatic screening for SARS-CoV-2 continue to be essential tools for mitigating virus transmission. Though COVID-19 diagnostics initially defaulted to oropharyngeal or nasopharyngeal sampling, the worldwide urgency to expand testing efforts spurred innovative approaches and increased diversity of detection methods. Strengthening innovation and facilitating widespread testing remains critical for global health, especially as additional variants emerge and other mitigation strategies are recalibrated.

AREAS COVERED

A growing body of evidence reflects the need to expand testing efforts and further investigate the efficiency, sensitivity, and acceptability of saliva samples for SARS-CoV-2 detection. Countries have made pandemic response decisions based on resources, costs, procedures, and regional acceptability - the adoption and integration of saliva-based testing among them. Saliva has demonstrated high sensitivity and specificity while being less invasive relative to nasopharyngeal swabs, securing saliva's position as a more acceptable sample type.

EXPERT OPINION

Despite the accessibility and utility of saliva sampling, global implementation remains low compared to swab-based approaches. In some cases, countries have validated saliva-based methods but face challenges with testing implementation or expansion. Here, we review the localities that have demonstrated success with saliva-based SARS-CoV-2 testing approaches and can serve as models for transforming concepts into globally-implemented best practices.