npj Vaccines (Dec 2022)

Comparing hybrid and regular COVID-19 vaccine-induced immunity against the Omicron epidemic

  • Lei Huang,
  • Francisco Tsz Tsun Lai,
  • Vincent Ka Chun Yan,
  • Franco Wing Tak Cheng,
  • Ching Lung Cheung,
  • Celine Sze Ling Chui,
  • Xue Li,
  • Eric Yuk Fai Wan,
  • Carlos King Ho Wong,
  • Ivan Fan Ngai Hung,
  • Chak Sing Lau,
  • Ian Chi Kei Wong,
  • Esther Wai Yin Chan

DOI
https://doi.org/10.1038/s41541-022-00594-7
Journal volume & issue
Vol. 7, no. 1
pp. 1 – 9

Abstract

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Abstract Evidence on the effectiveness of COVID-19 vaccines among people who recovered from a previous SARS-CoV-2 infection is warranted to inform vaccination recommendations. Using the territory-wide public healthcare and vaccination records of over 2.5 million individuals in Hong Kong, we examined the potentially differential risk of SARS-CoV-2 infection, hospitalization, and mortality between those receiving two homologous doses of BNT162b2 or CoronaVac versus those with a previous infection receiving only one dose amid the Omicron epidemic. Results show a single dose after a SARS-CoV-2 infection is associated with a lower risk of infection (BNT162b2: adjusted incidence rate ratio [IRR] = 0.475, 95% CI: 0.410–0.550; CoronaVac: adjusted IRR = 0.397, 95% CI: 0.309–0.511) and no significant difference was detected in the risk of COVID-19-related hospitalization or mortality compared with a two-dose vaccination regimen. Findings support clinical recommendations that those with a previous infection could receive a single dose to gain at least similar protection as those who received two doses without a previous infection.