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. 2022 Sep 30:12:100221.
doi: 10.1016/j.jvacx.2022.100221. eCollection 2022 Dec.

Immunogenicity to SARS-CoV-2 Omicron variant among school-aged children with 2-dose of inactivated SARS-CoV-2 vaccines followed by BNT162b2 booster

Napaporn Chantasrisawad  1   2   3 , Thanyawee Puthanakit  1   2 , Katesiree Kornsitthikul  4 , Peera Jaru-Ampornpan  5 , Monta Tawan  2 , Pariya Matapituk  4 , Jiratchaya Sophonphan  2 , Suvaporn Anugulruengkitt  1   2 , Auchara Tangsathapornpong  6 , Apirat Katanyutanon  7 ; KIDSBOOST study team*
Affiliations

Immunogenicity to SARS-CoV-2 Omicron variant among school-aged children with 2-dose of inactivated SARS-CoV-2 vaccines followed by BNT162b2 booster

Napaporn Chantasrisawad et al. Vaccine X. .

Abstract

Background: A primary series of 2-dose SARS-CoV-2 vaccines based on an ancestral strain generate inadequate neutralizing antibodies against the SARS-CoV-2 Omicron variant. This study aimed to describe the immune response from giving healthy school-aged children who previously received 2 inactivated vaccines an mRNA BNT162b2 booster.

Methods: Healthy children aged 5-11 years who received 2 doses of CoronaVac or Covilo were enrolled and received 10 µg BNT162b2 intramuscularly. Neutralizing antibody against Omicron variant was measured at pre-booster and 14-21 days post-booster by surrogate virus neutralization test (sVNT, %inhibition) and pseudovirus neutralization test (pVNT, ID50). Antibody responses were compared with a parallel cohort of children who received 2 doses of BNT162b2 3 weeks apart.

Results: From April to May 2022, 59 children with a mean age (SD) of 8.5 years (1.7) were enrolled: 20 CoronaVac and 39 Covilo recipients. The median interval from the primary series was 49 days (IQR 33-51). After booster, the geometric means (GMs) of sVNT and pVNT were 72.2 %inhibition (95 %CI 67.2-77.6) and 499 (95 %CI 399-624), respectively. The proportion of children with sVNT against Omicron strain ≥68 %inhibition increased from none to 70.2 %. The geometric mean ratio (GMR) of sVNT and pVNT compared with a parallel cohort were 4.3 and 12.2, respectively. The GMR of sVNT and pVNT between children who received booster dose at >6-week interval were 1.2 (95 %CI 1.1-1.3). and 1.8 (95 %CI 1.2-2.7) compared with 4-6 weeks interval.

Conclusion: A regimen of 2-dose of inactivated vaccine followed by BNT162b2 booster dose elicited high neutralizing antibody against the Omicron variants in healthy school-aged children.

Keywords: BNT162b2; Booster vaccination; Inactivated COVID-19 vaccine; SARS-CoV-2 antibody; School-aged children.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
GMs of sVNT against the Omicron variant (BA.1) (A) and GMs of pVNT against the Omicron variant (BA.2) (B) at day 14 after a BNT162b2 booster following the primary series with SARS-CoV-2 inactivated vaccine among school-aged children. P-value from t-test; PZ = BNT162b2 (Comirnaty, Pfizer-BioNTech), sVNT = surrogate virus neutralization test, pVNT = pseudovirus neutralization test, GMs = geometric means.
Fig. 2
Fig. 2
Local and systemic reactogenicities within 7 days after a BNT162b2 booster in children.
See this image and copyright information in PMC

References

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