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Microbes & Immunity Homologous versus heterologous COVID-19 vaccines

Figure 4. The number of vaccination strategies investigated. The vaccine name mentioned before the “/” is the first vaccine dose given (primary vaccination),
and the vaccine name mentioned after is the second dose (booster vaccination). In each combination, the vaccine named first was given as the first dose
and the vaccine named after was administered as the second dose

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to one another (12,906 EU/mL and 14,080 EU/mL, moderate geometric fold rise of 77 and 90, respectively.
respectively). 22 All heterologous vaccination groups had a significantly
In an observational study, Rose et al., reported a higher increase in spike IgG levels compared to the
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higher spike in IgG levels in participants who received homologous CoronaVac/CoronaVac group.
the heterologous ChAd/BNT compared to homologous 3.2.2. Antibodies to the RBD
ChAd/ChAd (783 BAU/mL to 123 BAU/mL). However,
the spike IgG antibody levels were higher in the Similar to the spike in IgG levels, the heterologous
homologous BNT/BNT group at 1,334 BAU/mL. In vaccination regimens generally induced high titers of
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the Com-COV 2 study conducted by Stuart et al., RBD antibodies compared to homologous vaccinations
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groups who received heterologous ChAd/mRNA-1273 (Table 3). In an RCT conducted in Brazil, Borobia
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and ChAd/NVX had higher spike IgG levels (P < 0.05) et al., observed a significant rise in RBD antibody titer
compared to the homologous ChAd/ChAd group with in participants who received heterologous ChAd/BNT
antibody levels of 20,114 ELU/mL, 5,597 ELU/mL and from 71.46 BAU/mL to 7,756.68 BAU/mL 14 days after
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1971 ELU/mL, respectively (Table 3). The heterologous the booster dose. Similarly, in an observational study by
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ChAd/mRNA-1273 and ChAd/NVX groups also showed Firinu et al., participants who received the heterologous
non-inferiority to the homologous group with a GMR of ChAd/BNT (497.6 AU/mL) showed a higher RBD
10.2 and 2.8, respectively. Among the groups who received antibody titer compared to the homologous ChAd (40.015
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heterologous BNT vaccines, the BNT/mRNA-1273 arm AU/mL) and homologous BNT (253.75 AU/mL) groups.
had the highest spike IgG levels at 22,978 ELU/ml and was A Swedish study involving ChAd-primed individuals
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higher compared to the homologous BNT/BNT arm. The receiving an mRNA-1273 booster showed remarkably
heterologous BNT/NVX had lower spike IgG antibody high RBD antibody levels (41680 BAU/mL) compared
levels at 8,874 ELU/ml. A RCT conducted in Brazil to individuals vaccinated with homologous ChAd (1224
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evaluated the immunogenicity of heterologous vaccines in BAU/mL). Another study that investigated vaccine
participants receiving an inactivated vaccine prime with combinations of ChAd with BBV152 showed that the
a mRNA boost or viral vector boost. The anti-spike IgG heterologous ChAd/BBV152 combination elicited higher
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levels for heterologous CoronaVac/BNT were highest with a RBD antibody levels (1,866 BAU/mL) when compared to
geometric fold rise of 152 from baseline, while participants the homologous BBV152 (710 BAU/mL) but was lower than
receiving CoronaVac/Ad 26 and CoronaVac/ChAd had a the homologous ChAd regime (2,260 BAU/mL) regime.
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Volume 1 Issue 2 (2024) 16 doi: 10.36922/mi.3757