Vaccines (Aug 2022)

Homologous or Heterologous COVID-19 Booster Regimens Significantly Impact Sero-Neutralization of SARS-CoV-2 Virus and Its Variants

  • Rome Buathong,
  • Taweewun Hunsawong,
  • Supaporn Wacharapluesadee,
  • Suriya Guharat,
  • Ratthapat Jirapipatt,
  • Sasiprapa Ninwattana,
  • Nattakarn Thippamom,
  • Anusara Jitsatja,
  • Anthony R. Jones,
  • Kamonthip Rungrojchareonkit,
  • Jindarat Lohachanakul,
  • Rungarun Suthangkornkul,
  • Kedsara Tayong,
  • Chonticha Klungthong,
  • Stefan Fernandez,
  • Opass Putcharoen

DOI
https://doi.org/10.3390/vaccines10081321
Journal volume & issue
Vol. 10, no. 8
p. 1321

Abstract

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We determined the levels of neutralizing antibodies against the SARS-CoV-2 ancestral strain, Delta and Omicron variants of concern (VOCs), in 125 healthcare workers who received CoronaVac as their primary vaccination and later received either a single ChAdOx1 or a combi-nation of two consecutive boosters using either two ChAdOx1 doses or a ChAdOx1 or BNT162b2 as the primary and second boosters, respectively, or two doses of BNT162b2. The titers 12 weeks after primary vaccination were inadequate to neutralize all strains. After a single ChAdOx1 booster, the levels of neutralization at Day 30 varied significantly, with only a small proportion of participants developing neutralizing titers against Omicron at Day 7 and 30. The two doses of ChAdOx1 as the booster induced the lowest activity. A combination ChAdOx1 and BNT162b2 induced greater neutralization than by two doses of ChAdOx1. Two doses of BNT162b2 as the booster had the maximal activity against Omicron VOC.

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