Omicron variant susceptibility to neutralizing antibodies induced in children by natural SARS-CoV-2 infection or COVID-19 vaccine

Emerg Microbes Infect. 2022 Dec;11(1):543-547. doi: 10.1080/22221751.2022.2035195.


The novel SARS-CoV-2 Omicron variant may increase the risk of re-infection and vaccine breakthrough infections as it possesses key mutations in the spike protein that affect neutralizing antibody response. Most studies on neutralization susceptibility were conducted using specimens from adult COVID-19 patients or vaccine recipients. However, since the paediatric population has an antibody response to SARS-CoV-2 infection that is distinct from the adult population, it is critical to assess the neutralization susceptibility of pediatric serum specimens. This study compared the neutralization susceptibility of serum specimens collected from 49 individuals of <18 years old, including 34 adolescent BNT162b2 (Pfizer-BioNTech) vaccine recipients, and 15 recovered COVID-19 patients aged between 2 and 17. We demonstrated that only 38.2% of BNT162b2 vaccine recipients and 26.7% of recovered COVID-19 patients had their serum neutralization titre at or above the detection threshold in our live virus microneutralization assay. Furthermore, the neutralizing antibody titer against the Omicron variant was substantially lower than those against the ancestral virus or the Beta variant. Our results suggest that vaccine recipients and COVID-19 patients in the pediatric age group will likely be more susceptible to vaccine breakthrough infections or reinfections due to the Omicron variant than previous variants.

Keywords: COVID-19 vaccine; Omicron variant; SARS-CoV-2; neutralizing antibody; variant of concern.

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • BNT162 Vaccine
  • COVID-19 Vaccines
  • COVID-19*
  • Child
  • Child, Preschool
  • Humans
  • SARS-CoV-2
  • Vaccination


  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines
  • BNT162 Vaccine

Supplementary concepts

  • SARS-CoV-2 variants

Grants and funding

This work was supported by Health and Medical Research Fund: [Grant Number COVID1903010, Project 1]; Hong Kong Collaborative Research Fund (CRF) 2020/21 and the CRF Coronavirus and Novel Infectious Diseases Research Exercises: [Grant Number C7149-20G]; Consultancy Service for Enhancing Laboratory Surveillance of Emerging Infectious Diseases and Research Capability on Antimicrobial Resistance for Department of Health of the HKSAR.