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Use of whole genome sequencing to estimate the contribution of immune evasion and waning immunity on decreasing COVID-19 vaccine effectiveness

As the number of cases and deaths among vaccinated and unvaccinated people rose following the introduction of the Delta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the summer of 2021, concerns regarding variant-specific immune evasion surfaced [1, 2]. While some studies found vaccine effectiveness against Delta was lower than previously circulating variants (such as Alpha) [3–11], other studies found the differences were likely driven by waning levels of protection, not variant-specific immune evasion [12–17].

Household transmission dynamics of seasonal human coronaviruses

Household transmission studies inform how viruses spread among close contacts, but few characterize household transmission of endemic coronaviruses. Our study highlights the need for large household studies to inform household transmission, the challenges in estimating household transmission probabilities from asymptomatic individuals, and implications for controlling endemic CoVs.

Assessment of a mass balance equation for estimating community-level prevalence of COVID-19 using wastewater-based epidemiology in a mid-sized city

Wastewater-based epidemiology (WBE) has emerged as a valuable epidemiologic tool to detect the presence of pathogens and track disease trends within a community. WBE overcomes some limitations of traditional clinical disease surveillance as it uses pooled samples from the entire community, irrespective of health-seeking behaviors and symptomatic status of infected individuals. WBE has the potential to estimate the number of infections within a community by using a mass balance equation, however, it has yet to be assessed for accuracy.

Reliable estimation of SARS-CoV-2 anti-spike protein IgG titers from single dilution optical density values in serologic surveys

Reliable and scalable seroepidemiology methods are needed to estimate SARS-CoV-2 incidence and monitor the dynamics of population-level immunity as the pandemic evolves. We aimed to evaluate the reliability of SARS-CoV-2 normalized ELISA optical density (nOD) at a single dilution compared to titers derived from serial dilutions. We conducted serial serosurveys within a community-based cohort in Salvador, Brazil. Anti-S IgG ELISA (Euroimmun AG) was performed with 5 serial 3-fold dilutions of paired sera from 54 participants.

Tracking coronavirus in wastewater

UF researchers track COVID-19 trends in an island community’s wastewater. The approach has broad implications as a public health surveillance tool.

Severe Acute Respiratory Syndrome Coronavirus 2 Delta Vaccine Breakthrough Transmissibility in Alachua County, Florida

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant has caused a dramatic resurgence in infections in the United Sates, raising questions regarding potential transmissibility among vaccinated individuals. Delta infection transmissibility and general viral RNA quantification patterns in vaccinated individuals suggest limited levels of sterilizing immunity that need to be considered by public health policies. In particular, ongoing evaluation of vaccine boosters should specifically address whether extra vaccine doses curb breakthrough contribution to epidemic spread.

Animal alphacoronaviruses found in human patients with acute respiratory illness in different countries

Here we review the existing evidence of animal alphacoronaviruses (Alphacoronavirus 1 species) circulating in human patients with acute respiratory illness. Thus far, the viruses similar to canine, feline and porcine alphacoronaviruses (including the most recent CCoV-HuPn-2018 and HuCCoV_Z19) have been detected in humans in Haiti, Malaysia, Thailand, and USA. The available data suggest that these viruses emerged in different geographic locations independently and have circulated in humans for at least 20 years.