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Quantitative Issues in Cancer Research Working Seminar
February 13 @ 1:00 pm - 1:50 pm
Doctoral Student, Department of Biostatistics, Harvard University
“Duration of viral shedding with postvaccination SARS-CoV-2 infections & Linear growth and weight gain from birth to age two: A longitudinal cohort study in Amhara, Ethiopia”
ABSTRACTS: Project 1: Isolation guidelines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are largely derived from data collected prior to the emergence of the delta variant. We followed a cohort of ambulatory patients with postvaccination breakthrough SARS-CoV-2 infections with longitudinal collection of nasal swabs for SARS-CoV-2 viral load quantification, whole-genome sequencing, and viral culture. All delta variant infections in our cohort were symptomatic, compared with 64% of non-delta variant infections. Symptomatic delta variant breakthrough infections were characterized by higher initial viral load, longer duration of virologic shedding by PCR, greater likelihood of replication-competent virus at early stages of infection, and longer duration of culturable virus compared with non-delta variants. The duration of time since vaccination was also correlated with both duration of PCR positivity and duration of detection of replication-competent virus. Nonetheless, no individuals with symptomatic delta variant infections had replication-competent virus by day 10 after symptom onset or 24 hours after resolution of symptoms. These data support US CDC isolation guidelines as of November 2021, which recommend isolation for 10 days or until symptom resolution and reinforce the importance of prompt testing and isolation among symptomatic individuals with delta breakthrough infections.
Project 2: The Sustainable Development Goals set out an ambitious goal to end all forms of malnutrition by 2030. Although there has been a reduction in stunting (low height for age) and wasting (low height for weight), the prevalence of malnutrition in Ethiopia is still high. To improve nutritional outcomes, granular data are needed to determine key time points for growth and weight faltering. The Birhan maternal and child health study in North Shewa Zone in Amhara, Ethiopia, collected longitudinal data used in this study to determine key time points for growth and weight faltering. We investigated growth and weight faltering at birth, four weeks, six, 12 and 24 months. Our findings indicate that median population-level length and weight among children in this population are consistently below global standards from birth to age two. Growth velocity and weight gain was slowest compared to global standards during the neonatal period and after children reached six months of age. The prevalence of stunting was highest at age two (56.7%), whereas the prevalence of wasting was lower and peaked at birth (18.4%). Incidence of stunting increased over time whereas it decreased for wasting. We also found substantial within-individual heterogeneity in anthropometric measurements. Overall, the evidence from this study highlights a chronically malnourished population compared to global standards, with much of the burden driven by growth and weight faltering during the pre- and neonatal periods as well as after 6 months of age. To end all forms of malnutrition, growth and weight faltering in populations such as that in young children in Amhara, Ethiopia needs to be addressed.