Oral Vaccination Protects Against Severe Acute Respiratory Syndrome Coronavirus 2 in a Syrian Hamster Challenge Model

J Infect Dis. 2022 Jan 5;225(1):34-41. doi: 10.1093/infdis/jiab561.


Background: Vaccines that are shelf stable and easy to administer are crucial to improve vaccine access and reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission around the world.

Methods: In this study, we demonstrate that an oral, adenovirus-based vaccine candidate protects against SARS-CoV-2 in a Syrian hamster challenge model.

Results: Hamsters administered 2 doses of VXA-CoV2-1 showed a reduction in weight loss and lung pathology and had completely eliminated infectious virus 5 days postchallenge. Oral immunization induced antispike immunoglobulin G, and neutralizing antibodies were induced upon oral immunization with the sera, demonstrating neutralizing activity.

Conclusions: Overall, these data demonstrate the ability of oral vaccine candidate VXA-CoV2-1 to provide protection against SARS-CoV-2 disease.

Keywords: COVID; SARS-CoV-2; hamster; mucosal; oral vaccine.

MeSH terms

  • Adenovirus Vaccines / administration & dosage*
  • Adenovirus Vaccines / immunology
  • Animals
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 / prevention & control*
  • COVID-19 / virology
  • COVID-19 Vaccines / administration & dosage*
  • COVID-19 Vaccines / immunology
  • Cricetinae
  • Mesocricetus*
  • SARS-CoV-2
  • Spike Glycoprotein, Coronavirus
  • Vaccination


  • Adenovirus Vaccines
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines
  • Spike Glycoprotein, Coronavirus