Breastfeeding Initiation Rates and COVID-19 Outcomes: An Ecological Study of U.S. Counties
Faculty Mentor
Professor Jian Zhang
Location
Russell Union Ballroom
Type of Research
On-going
Session Format
Poster Presentation
College
Jiann-Ping Hsu College of Public Health
Department
Biostatistics Epidemiology & Environmental Health Sciences
Abstract
Objective: Although animal studies suggest that long-term, maternally acquired cellular immunity may exist, epidemiologic evidence is limited. To explore the potential for long-term maternal immune protection, we examined COVID-19 disease burden across U.S. communities with varying breastfeeding initiation rates, adjusting for county-level sociodemographic characteristics, geographic features, healthcare workforce density, mask-wearing behavior, vaccination coverage, and political context.
Methods: Using data from 3,210 U.S. counties and county equivalents from March 1, 2020, through February 28, 2022, we calculated daily COVID‑19 incidence, mortality, and case‑fatality rates. Adjusted rate ratios (RRs) were estimated for counties with low (< 73%) and moderate (73–88%) breastfeeding initiation rates (BFIR) compared with counties with high BFIR (≥89%), controlling for county-level characteristics relevant to COVID-19 transmission and mitigation.
Results: Counties with low BFIR experienced substantially higher COVID‑19 mortality during major national surges, reaching 10 deaths per million on January 8, 2021 (winter surge) and September 1, 2021 (Delta surge) - a pattern not observed in high‑BFIR counties. Associations differed by rurality. Low‑BFIR rural counties consistently exhibited higher daily incidence and mortality than high‑BFIR rural counties, particularly during the pre-vaccine era. At the peak of the largest pre-vaccine wave (January 8, 2021), adjusted RRs for daily incidence and mortality in low‑BFIR rural counties were 1.36 (95% CI: 1.30–1.42) and 1.65 (1.19–2.30), respectively. In urban areas, case‑fatality rates were significantly higher in low‑BFIR counties across nearly all major surges, with RRs of 1.39 (1.18–1.65) during the 2020 summer surge, 1.45 (1.23–1.70) during the 2020 winter surge.
Conclusions: Because most COVID-19 morbidity and mortality occurred in adults, the observed associations are consistent with the possibility of long-term maternal immune influences. These ecological findings raise the possibility that breastfeeding may contribute to long-term immune protection against emerging infectious pathogens, underscoring the need for individual-level studies.
Program Description
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Start Date
4-23-2026 2:00 PM
End Date
4-23-2026 4:00 PM
Recommended Citation
Kengne, Francis B., "Breastfeeding Initiation Rates and COVID-19 Outcomes: An Ecological Study of U.S. Counties" (2026). GS4 Student Scholars Symposium. 161.
https://digitalcommons.georgiasouthern.edu/research_symposium/2026/2026/161
Breastfeeding Initiation Rates and COVID-19 Outcomes: An Ecological Study of U.S. Counties
Russell Union Ballroom
Objective: Although animal studies suggest that long-term, maternally acquired cellular immunity may exist, epidemiologic evidence is limited. To explore the potential for long-term maternal immune protection, we examined COVID-19 disease burden across U.S. communities with varying breastfeeding initiation rates, adjusting for county-level sociodemographic characteristics, geographic features, healthcare workforce density, mask-wearing behavior, vaccination coverage, and political context.
Methods: Using data from 3,210 U.S. counties and county equivalents from March 1, 2020, through February 28, 2022, we calculated daily COVID‑19 incidence, mortality, and case‑fatality rates. Adjusted rate ratios (RRs) were estimated for counties with low (< 73%) and moderate (73–88%) breastfeeding initiation rates (BFIR) compared with counties with high BFIR (≥89%), controlling for county-level characteristics relevant to COVID-19 transmission and mitigation.
Results: Counties with low BFIR experienced substantially higher COVID‑19 mortality during major national surges, reaching 10 deaths per million on January 8, 2021 (winter surge) and September 1, 2021 (Delta surge) - a pattern not observed in high‑BFIR counties. Associations differed by rurality. Low‑BFIR rural counties consistently exhibited higher daily incidence and mortality than high‑BFIR rural counties, particularly during the pre-vaccine era. At the peak of the largest pre-vaccine wave (January 8, 2021), adjusted RRs for daily incidence and mortality in low‑BFIR rural counties were 1.36 (95% CI: 1.30–1.42) and 1.65 (1.19–2.30), respectively. In urban areas, case‑fatality rates were significantly higher in low‑BFIR counties across nearly all major surges, with RRs of 1.39 (1.18–1.65) during the 2020 summer surge, 1.45 (1.23–1.70) during the 2020 winter surge.
Conclusions: Because most COVID-19 morbidity and mortality occurred in adults, the observed associations are consistent with the possibility of long-term maternal immune influences. These ecological findings raise the possibility that breastfeeding may contribute to long-term immune protection against emerging infectious pathogens, underscoring the need for individual-level studies.
