RESUMEN
Objective: To compare the immune response of hybrid immunity - arising from SARS-CoV-2 infection and mRNA BNT162b2 vaccination - to that of 2-doses of vaccine. Methods: In a subanalysis of BNT162b2 vaccine trial in 5 to 11-year-old children, There were 179 children who had hybrid immunity compared with 134 children with solely 2-dose vaccine. The immunological outcome was a surrogate virus neutralization test (sVNT) against the Omicron strain, BA.1, (%inhibition). An sVNT level ≥68 % inhibition was considered as protective immune response. Results: From February to April 2022, 179 children had COVID-19 natural infection resulting in hybrid immunity included: Group1;prior vaccination(n = 17), Group2;after the first dose(n = 61), and Group3;after the second dose(n = 97). The proportion of children with protective immune response was higher in Group 3 and Group 1 - 61.9 % and 58.8 %, compared to 36.1 % and 34.3 % in Group 2 and comparator group (2 doses of vaccine), respectively. The geometric mean % inhibition of sVNT was higher in Group 1 (68.5, 95 %CI 55.5-84.6) and Group 3 (63.5, 95 %CI 55.5-72.6), followed by comparator group (49.6, 95 %CI 44.8-54.9) and Group 2 (42.1, 95 %CI 34.6-51.3), p < 0.001. Conclusions: Immune response that arises from BNT162b2 vaccine after natural infection and infection after 2 doses of BNT162b2 was higher than infection after partially-vaccinated children.
RESUMEN
This study aimed to assess long COVID, and describe immunogenicity against Omicron variants following BNT162b2 vaccination. A prospective cohort study was conducted among children (aged 5-11) and adolescents (aged 12-17) who had SARS-CoV-2 infection from July to December 2021 (Delta predominant period). Long COVID symptoms were assessed by questionnaires at 3 months after infection. Immunogenicity was evaluated by using a surrogate virus-neutralizing antibody test (sVNT) against the Omicron variant. We enrolled 97 children and 57 adolescents. At 3 months, 30 children (31%) and 34 adolescents (60%) reported at least one long COVID symptom, with respiratory symptoms prevailing (25% children and 32% adolescents). The median time from infection to vaccination was 3 months in adolescents and 7 months in children. At 1 month following vaccination, in children who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 86.2% inhibition (71.1-91.8) and 79.2% inhibition (61.5-88.9), respectively (p = 0.26). Among adolescents who received one-dose and two-dose BNT162b2 vaccines, the median (IQR) sVNT against Omicron was 64.4% inhibition (46.8-88.8) and 68.8% inhibition (65.0-91.2) (p = 0.64). Adolescents had a higher prevalence of long COVID than children. Immunogenicity against the Omicron variant after vaccination was high and did not vary between one or two doses of the vaccine in either children or adolescents.
RESUMEN
Adolescents with underlying diseases are at risk of severe COVID-19. The immune response of BNT162b2 may be poor among immunocompromised adolescents. We aim to describe immunogenicity of mRNA BNT162b2 among adolescents who are immunocompromised or have chronic diseases. We recruited adolescents 12-18 years of age; group A impaired-immunity (post-transplantation, cancer, on immunosuppressive drugs) and group B chronic diseases. A two-dose regimen of BNT162b2 was given. Immunogenicity was determined by surrogate virus neutralization test (sVNT) and IgG against receptor-binding domain (RBD). From August to October 2021, 312 adolescents, with a median age (IQR) of 15 years (13.7-16.5), were enrolled (group A 100, group B 212). The geometric means (GMs) of sVNT (% inhibition) against Delta strain and anti-RBD IgG (BAU/mL) after the 2nd dose among group A were: post-transplantation recipients 52.9 (95% CI 37.7-74.2) and 233.6 (95% CI 79-690.6); adolescents with cancer 62.3 (95% CI 29.2-133.1) and 214.9(95% CI 34.2-1348.6); and adolescents with other immunosuppressive conditions 66.7 (95% CI 52.4-84.8) and 849.8 (95% CI 393.4-1835.8). In group B were: adolescents living with HIV 98 (95% CI 97.3-98.8) and 3240.3 (95% CI 2699-3890.2), and adolescents with other chronic disease 98.6 (95% CI 98.3-98.9) and 3818.5 (95% CI 3490.4-4177.4). At day 90, immunity declined; among impaired-immunity participants were 43.9 (95% CI 30.8-62.4) and 178.7 (95% CI 91.2-350.1) and adolescents with chronic diseases were 90.6 (95% CI 88.4-92.8) and 1037.1 (95% CI 933.3-1152.5). In conclusion, adolescents with impaired immunity had a poor response to 2-doses of BNT162b2, additional dose should be considered. Adolescents with chronic diseases had excellent response but immunity waned after 3 m, booster dose may be required.