In several countries, thrombotic events after vaccination with ChAdOx1 nCoV-19 have led to heterologous messenger RNA (mRNA) boosting. We tested the antibody response to SARS-CoV-2 spike protein four weeks after heterologous priming with the ChAdOx1 (ChAd) vector vaccine followed by boosting with BNT162b2(ChAd/BNT), comparing data of homologous regimen (BNT/BNT, ChAd/ChAd) subjects positive for SARS-CoV-2 after the first dose of BNT162b2 (BNT1dose/CoV2) and convalescent COVID-19. Methods: healthy subjects naïve for SARS-CoV-2 infection were assessed for serum IgG anti-S-RBD response 21 days after priming (T1), 4 (T FULL ) and 15 (T 15W ) weeks after booster dose. Results: The median IgG anti-S-RBD levels at T FULL of Chad/BNT group were significantly higher than the BNT/BNT group and ChAd/ChAd. Those of BNT/BNT group were significantly higher than ChAd/ChAd. IgG anti-S-RBD of BNT1dose/CoV2 group were similar to BNT/BNT, ChAd/BNT and ChAd/Chad group. The levels among COVID-19 convalescents were significantly lower than ChAd/BNT, BNT/BNT, ChAd/Chad and BNT1dose/CoV2. The proportion of subjects reaching an anti-S-RBD titer >75 AU/mL, correlated with high neutralizing titer, was 94% in ChAd/BNT and BNT/BNT, 60% in BNT1dose/CoV2, 25% in ChAd/ChAd and 4.2% in convalescents. At T 15W the titer of ChAd/BNT was still significantly higher than other vaccine schedules, while the anti-S-RBD decline was reduced for ChAd/ChAd and similar for other combinations. Conclusion: Our data highlight the magnitude of IgG anti-S-RBD response in ChAd/BNT dosing, supporting the current national guidelines for heterologous boosting
【저자키워드】 COVID-19, vaccination, immunogenicity, BNT162b2, ChAdOx1, Heterologous, 【초록키워드】 SARS-CoV-2, IgG, Vaccine, SARS-COV-2 infection, mRNA, SARS-CoV-2 spike protein, convalescent, homologous, booster dose, ChAdOx1 nCoV-19, Neutralizing titer, regimen, Messenger RNA, subject, first dose, combinations, naïve, priming, serum IgG, positive, significantly lower, thrombotic event, highlight, tested, proportion, median, correlated, magnitude, significantly higher, healthy subject, the antibody response, was reduced, national guideline, of BNT162b2, were assessed, 【제목키워드】 response, ChAdOx1 nCoV-19,