COVID-19 IN CHILDREN: ANTIBODY RESPONSE INDUCED BY INFECTION AND VACCINATION, HYBRID IMMUNITY AND LONG-TERM SYMPTOMS

ARRUVITO LOURDES

Congreso; Reunión Anual de Sociedades de Biociencias SAIC-SAI-FAIC-SAFIS; 2022

Children and youth infected with SARS-CoV-2 frequently show an asymptomatic or mild disease contrasting with other viral respiratory infections which can induce a severe disease. It has been suggested that children develop an earlier and more robust innate immune response upon SARS-CoV-2 infection compared with adults. The possible contribution of a more efficient adaptive immune response to the favorable outcome of pediatric COVID-19 has not yet been determined. Here, we show that in response to SARS-CoV-2 infection, children developed a higher and more sustained antibody response compared with adults. When measured at 7-17 months after infection, both the titers of IgG antibodies directed to the spike protein of SARS-CoV-2, and the plasma neutralising activity against the Wuhan original variant and the VOCs Delta and Omicron were higher in children compared with adults. We also found that vaccination with two-doses of the inactivated BBIBP-CorV vaccine or the mRNA vaccines BNT162b2 and mRNA-1273 further increased the plasma neutralising activity against Delta and Omicron in previously infected children. The special signature of the antibody response in children upon SARS-CoV-2 infection may provide some degree of immune advantage compared to adults in terms of adaptive immunity. This observation together with the ability of the current anti-SARS-CoV2 vaccines to further enhance the antibody response against VOCs including Delta and Omicron in previously infected children, may inform vaccination strategies in the pediatric population.While long COVID is widely recognized in adults, its existence in children is more controversial. We also studied the long-term symptoms and associated risk factors for persistent symptoms beyond 3 months of COVID-19 in pediatric population. Almost 30% of children that suffered COVID-19 reported at least one persistent symptom. Compared with the control group, SARS-CoV-2 infection in children increased 3 to 6 folds the risk of having headache, dizziness, loss of taste, dyspnea, cough, fatigue, muscle pain and loss of weight. Loss of smell was only reported in infected children. Finally, older age, symptomatic COVID-19 and comorbidities were predictor variables significantly associated with a higher risk of developing long-term symptoms. Pediatric long COVID is a new condition that requires urgent public health policies.