Incidence and Associated Factors of COVID-19 Infection among Newborns: A Cross-Sectional Study in Thailand

Abstract

Background and Rationale: COVID-19 is the pandemic that has significantly impacted disease control measures, daily life, and healthcare services. Pregnant women and newborns are vulnerable populations at increased risk of severe illness and adverse outcomes. This study aimed to identify the incidence and associated factors of newborn COVID-19 infection. Understanding these would benefit in developing effective strategies to mitigate the risks associated with COVID-19 infection during pregnancy and infancy.
Methodology: This cross-sectional quantitative study utilized data from a country-wide reporting system of pregnant and postpartum women infected with COVID-19 and their newborns in Thailand. The study included 6,048 newborns born to infected mothers from December 2020 to May 2022. The outcome was the incidence of newborns infected with COVID-19. The exposure factors were mothers’ characteristics including age, nationality, vaccination status, gestational age at infection detection and at delivery, the severity of COVID-19 infection, delivery mode, and newborns’ characteristics including birth weight, mother-newborn separation after birth, and infant feeding. Multivariable logistic regression was used to examine associations between characteristics and newborn COVID-19 infection.
Results: The proportion of newborns infected with COVID-19 was relatively low (6.4%). Maternal age was associated with infection risk, with newborns of mothers aged 20-34 years (adjusted odds ratio: AOR = 0.60, 95%CI: 0.43-0.81) and ≥ 35 years (AOR = 0.64, 95%CI: 0.44-0.93) having a lower likelihood of infection compared to the youngest age group. Newborns of mothers known of infection during postpartum had a higher likelihood of infection (AOR = 3.75, 95% CI: 2.16-6.51). The severity of COVID-19 infection in mothers was inversely associated with newborn infection risk (AOR = 0.67, 95% CI: 0.47-0.96). Term newborns had a lower likelihood of being infected with COVID-19 (AOR = 0.49, 95% CI: 0.29-0.84) compared to preterm newborns. Complete separation of mother and newborn after birth was associated with the lowest likelihood of infection (AOR = 0.18, 95% CI: 0.11-0.30). Newborns who were fed breast milk substitutes, or a combination of substitutes and maternal milk had a higher likelihood of infection (AOR = 4.16, 95% CI: 2.32-7.45) compared to those directly breastfed or fed with expressed breastmilk.
Conclusion: This study contributes to the understanding of newborn COVID-19 infection and its risk factors in Thailand. The relatively low proportion of infected newborns and the identified factors provide guidance for preventive measures and optimizing care during the pandemic. Continued research is needed to further explore these factors and address knowledge gaps for effective prevention and management strategies.