Antibody persistence and safety after heterologous boosting with orally aerosolised Ad5-nCoV in individuals primed with two-dose CoronaVac previously: 12-month analyses of a randomized controlled trial

Abstract

Antibody persistence and safety up to 12 months of heterologous orally administered adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) in individuals who were primed with two-dose inactivated SARS-CoV-2 vaccine (CoronaVac) previously, has not been reported yet. This randomized, open-label, single-centre trial included Chinese adults who have received two-dose CoronaVac randomized to low-dose or high-dose aerosolised Ad5-nCoV group, or CoronaVac group. In this report, we mainly evaluated the geometric mean titres (GMTs) of neutralizing antibodies (NAbs) against live wild-type SARS-CoV-2 virus and omicron BA.4/5 pseudovirus at 12 months after the booster dose and the incidence of serious adverse events (SAEs) till month 12. Of 419 participants, all were included in the safety analysis and 120 (28.64%) were included in the immunogenicity analysis. Serum NAb GMT against live wild-type SARS-CoV-2 was 204.36 (95% CI 152.91, 273.14) in the low-dose group and 171.38 (95% CI 121.27, 242.19) in the high-dose group at month 12, significantly higher than the GMT in the CoronaVac group (8.00 [95% CI 4.22, 15.17], p < 0.0001). Serum NAb GMT against omicron BA.4/5 pseudovirus was 40.97 (95% CI 30.15, 55.67) in the low-dose group and 35.08 (95% CI 26.31, 46.77) in the high-dose group at month 12, whereas the GMT in the CoronaVac group was below the lower limit of detection. No vaccine-related SAEs were observed. Orally administered aerosolised Ad5-nCoV following two-dose CoronaVac priming has a good safety profile and is persistently more immunogenic than three-dose CoronaVac within 12 months after the booster dose. Trial registration: .

Application of “B+1” heterologous boosting strategy for preventing infection of SARS-CoV-2 variants with resistance to broad-spectrum coronavirus vaccines

“…The orally aerosolized Ad5-nCoV is supposed to be able to elicit respiratory mucosal immunity such as secretory IgA, which would play an important role in preventing viral transmission. These results confirmed that heterologous boosting is more effective in eliciting NAb responses than the homologous boosting regimen [ 6 ].…”

Mucosal vaccine-induced cross-reactive CD8+ T cells protect against SARS-CoV-2 XBB.1.5 respiratory tract infection

“…Two nasally delivered, adenoviral-vectored COVID-19 vaccines (iNCOVACC (chimpanzee adenoviral (ChAd)-SARS-CoV-2-S) and Convidecia Air (human Ad5-nCoV-inhaled)) targeting the S protein of the Wuhan-1 strain were approved in late 2022 in India and China, respectively, for use as primary or booster immunizations. Nonetheless, data on the efficacy of these nasally delivered vaccines against transmission 22 , 23 or circulating antigen-shifted Omicron strains are absent.…”

Safety, immunogenicity, and protective effective of inhaled COVID‐19 vaccines: A systematic review and meta‐analysis

“…Full-text screening was performed for 20 articles, of which 5 articles did not meet the eligibility criteria and were excluded. A total of 15 studies [18][19][20][32][33][34][35][36][37][38][39][40][41][42][43] (11 analyzing safety, 13 analyzing immunogenicity, and 3 analyzing effective) were found to meet the inclusion criteria and were included in the systematic review and meta-analysis. The PRISMA flowchart depicted the process of article screening and selection (Figure 1).…”

“…Data are available online for the included studies. [18][19][20][32][33][34][35][36][37][38][39][40][41][42][43]…”