Frequency of Lymphopenia in Infants with COVID-19; Vaccination Dilemma

Abstract Objective Although coronavirus disease 2019 (COVID-19) is mainly a respiratory system disease, many hematological abnormalities have been reported. Due to the application of primary immunization in infancy, our study aimed to examine the relationship between lymphopenia frequency and duration of lymphopenia in infants with COVID-19. Methods The files of infants hospitalized with the diagnosis of COVID-19 in the Pediatric Pandemic Service of Istanbul Medical Faculty between January 2020 and October 2022 were evaluated retrospectively. Demographic characteristics, leukocyte, lymphocyte count, comorbidity, hospitalization, and lymphopenia recovery time were recorded. Results In this study, 93 infants with COVID-19 were included. Lymphopenia was detected in 62 of these patients (n = 62/93, 66.7%). The 47.3% of the patients were female (n = 44) and the mean age was 6 ± 3.42 months. Comorbidities were detected in the 33% of the patients. Lymphopenia resolved in an average of 11 days. While the mean hospitalization period of patients with lymphopenia was 3.6 ± 2.9 (minimum: 1 and maximum: 15) days, the mean hospitalization period of patients without lymphopenia was 2.5 days. Leukopenia (p: 0.014) and lymphopenia (p: 0.005) were more common in infants with chronic disease. Similarly, the duration of hospitalization and recovery from lymphopenia were statistically significantly longer (p: 0.016). A statistically significant correlation was found between the duration of lymphopenia recovery and the duration of hospitalization (p: 0.001). Conclusion Although we found lymphopenia as a common finding in infancy in our study, it was not observed frequently enough to require the postponement of the vaccination program due to its short duration. Vaccination should not be delayed due to lymphopenia in infants with COVID-19 to avoid a missed opportunity for vaccination.