Risk Factors for Coronavirus Disease 2019 Hospitalization and Vaccination Impact Among Pediatric Solid Organ...

While vaccination is a key strategy to mitigate the severity of coronavirus disease 2019 (COVID-19) in children, the risk factors for symptomatic, medically attended (hereon referred to as "symptomatic") COVID-19 and the impact of vaccination are not well defined among pediatric solid organ transplant recipients (PSOTR).

PSOTR aged six months through 21 years at 11 centers in the Pediatric Infectious Diseases Transplant Network (PIDTRAN) were analyzed retrospectively for symptomatic COVID-19 between July 2021 and May 2023. Using a Cox proportional hazards model, risk factors associated with COVID-19-associated hospitalization, in-hospital oxygen use, mechanical ventilation, and the impact of COVID-19 vaccination were analyzed.

Of 1370 PSOTR, 410 (29%) had symptomatic COVID-19 infection. Among those with symptomatic infection, 115 (28%) were hospitalized, 35 required in-hospital oxygen, and three required mechanical ventilation. In the study, 45% were unvaccinated against COVID-19. Compared to unvaccinated PSOTR, incompletely vaccinated PSOTR had 56% lower hazard (95% CI 0.26, 0.72, p = 0.001) of COVID-19-associated hospitalization whereas completely vaccinated did not have a statistically significant difference in hazard of hospitalization. Receipt of at least one dose of the bivalent vaccine was also associated with 92.5% lower hazard (95% CI 0.010, 0.55, p = 0.011) of hospitalization. Risk factors for hospitalization included chronic kidney disease, underlying heart disease, neurodevelopmental delay, and lymphocytopenia.

Most PSOTR with symptomatic COVID-19 did not require hospitalization or respiratory support. Several comorbidities and lymphocytopenia are associated with severe COVID-19 in PSOTR. COVID-19 vaccination, mostly, protected PSOTR against COVID-19-associated hospitalization, but vaccine uptake among PSOTR was low.