Safety and immunogenicity of heterologous boosting with orally aerosolised or intramuscular Ad5-nCoV vaccine and homologous boosting with inactivated vaccines (BBIBP-CorV or CoronaVac) in children and adolescents: a randomised, open-label, parallel-controlled, non-inferiority, single-centre study.

BACKGROUND: Heterologous booster immunisation with orally administered aerosolised Ad5-nCoV vaccine (AAd5) has been shown to be safe and highly immunogenic in adults. Here, we aimed to assess the safety and immunogenicity of heterologous booster immunisation with orally administered AAd5 in children and adolescents aged 6-17 years who had received two doses of inactivated vaccine (BBIBP-CorV or CoronaVac). METHODS: We did a randomised, open-label, parallel-controlled, non-inferiority study to assess the safety and immunogenicity of heterologous booster immunisation with AAd5 (0·1 mL) or intramuscular Ad5-nCoV vaccine (IMAd5; 0·3 mL) and homologous booster immunisation with inactivated vaccine (BBIBP-CorV or CoronaVac; 0·5 mL) in children (aged 6-12 years) and adolescents (aged 13-17 years) who had received two doses of inactivated vaccine at least 3 months earlier in Hunan, China. Children and adolescents who were previously immunised with two-dose BBIBP-CorV or CoronaVac were recruited for eligibility screening at least 3 months after the second dose. A stratified block method was used for randomisation, and participants were stratified by age and randomly assigned (3:1:1) to receive AAd5, IMAd5, or inactivated vaccine. The study staff and participants were not masked to treatment allocation. Laboratory and statistical staff were masked during the study. In this interim analysis, adverse events within 14 days and geometric mean titre (GMT) of serum neutralising antibodies on day 28 after the booster vaccination, based on the per-protocol population, were used as the primary outcomes. The analysis of non-inferiority was based on comparison using a one-sided 97·5% CI with a non-inferiority margin of 0·67. This study was registered at ClinicalTrials.gov, NCT05330871, and is ongoing. FINDINGS: Between April 17 and May 28, 2022, 436 participants were screened and 360 were enrolled: 220 received AAd5, 70 received IMAd5, and 70 received inactivated vaccine. Within 14 days after booster vaccination, vaccine-related adverse reactions were reported: 35 adverse events (in 13 [12%] of 110 children and 22 [20%] of 110 adolescents) in 220 individuals in the AAd5 group, 35 (in 18 [51%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 13 (in five [14%] of 35 children and eight [23%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. Solicited adverse reactions were also reported: 34 (13 [12%] of 110 children and 21 [10%] of 110 adolescents) in 220 individuals in the AAd5 group, 34 (17 [49%] of 35 children and 17 [49%] of 35 adolescents) in 70 individuals in the IMAd5 group, and 12 (five [14%] of 35 children and seven [20%] of 35 adolescents) in 70 individuals in the inactivated vaccine group. The GMTs of neutralising antibodies against ancestral SARS-CoV-2 Wuhan-Hu-1 (Pango lineage B) in the AAd5 group were significantly higher than the GMTs in the inactivated vaccine group (adjusted GMT ratio 10·2 [95% CI 8·0-13·1]; p<0·0001). INTERPRETATION: Our study shows that a heterologous booster with AAd5 is safe and highly immunogenic against ancestral SARS-CoV-2 Wuhan-Hu-1 in children and adolescents. FUNDING: National Key R&D Program of China.

[Expression of Dnajb13 and its involvement in the apoptosis of spermatogenic cells in the testis of the mouse with cryptorchidism].

OBJECTIVE: To study the mRNA and protein expressions of Dnajb13 and its localization in the testis of the mouse with cryptorchidism and its association with the apoptosis of spermatogenic cells. METHODS: The localization of Dnajb13 in the spermatogenic cells of 8-week-old mice was detected by immunohistochemistry. The model of unilateral cryptorchidism was surgically established in the mice and verified by TUNEL, flow cytometry and morphological observation. The apoptosis of the spermatogenic cells was analyzed and the mRNA and protein expressions of Dnajb13 in both cryptorchid and healthy testes were determined by quantitative polymerase chain reaction (qPCR), Western blot and immunohistochemistry at 1, 2, 3, 4, 5, 6, 9 and 15 days after modeling. RESULTS: Immunohistochemistry showed that Dnajb13 was localized in the elongated spermatids at steps 9－16 of spermiogenesis in the testis tissue of the healthy mice. TUNEL and flow cytometry manifested that the round spermatids at step 1 and primary spermatocytes in miosis were most sensitive to elevated temperature. After modeling, apoptosis was first observed in the round spermatids at steps 1－8, which were decreased from 17.09% to 6.52% (P < 0.05), then in the spermatids during metamorphosis at steps 9－16, and then in the primary spermatocytes. At 3 days after surgery, the expression of Dnajb13 mRNA in the cryptorchid testis was 1.6 times higher than that in the healthy one (P < 0.05) and decreased at 4 days, 1.2 times that of the normal. The expression of the Dnajb13 protein exhibited no significant change at 1－3 days, but a 0.68-fold reduction at 4 days (P < 0.05) and a 0.4-fold reduction at 9 days. Immunohistochemical staining revealed the expression of the Dnajb13 protein in the apoptotic multinucleated giant cells at 6 days. CONCLUSIONS: Dnajb13 is localized in the spermatids during metamorphosis and in the tails of mature sperm in adult mice, involved in sperm metamorphosis and sperm flagellum formation, and expressed in apoptotic multinucleated giant cells in the cryptorchid testis, which may be associated with the apoptosis of round spermatids at stages Ⅵ－Ⅷ.