Relative infectiousness of SARS-CoV-2 vaccine breakthrough infections, reinfections, and primary infections. Academic Article uri icon

Overview

abstract

  • SARS-CoV-2 breakthrough infections in vaccinated individuals and in those who had a prior infection have been observed globally, but the transmission potential of these infections is unknown. The RT-qPCR cycle threshold (Ct) value is inversely correlated with viral load and culturable virus. Here, we investigate differences in RT-qPCR Ct values across Qatar's national cohorts of primary infections, reinfections, BNT162b2 (Pfizer-BioNTech) breakthrough infections, and mRNA-1273 (Moderna) breakthrough infections. Our matched-cohort analyses of the randomly diagnosed infections show higher mean Ct value in all cohorts of breakthrough infections compared to the cohort of primary infections in unvaccinated individuals. The Ct value is 1.3 (95% CI: 0.9-1.8) cycles higher for BNT162b2 breakthrough infections, 3.2 (95% CI: 1.9-4.5) cycles higher for mRNA-1273 breakthrough infections, and 4.0 (95% CI: 3.5-4.5) cycles higher for reinfections in unvaccinated individuals. Since Ct value correlates inversely with SARS-CoV-2 infectiousness, these differences imply that vaccine breakthrough infections and reinfections are less infectious than primary infections in unvaccinated individuals. Public health benefits of vaccination may have been underestimated, as COVID-19 vaccines not only protect against acquisition of infection, but also appear to protect against transmission of infection.

authors

  • Abu-Raddad, Laith Jamal
  • Chemaitelly, Hiam Souheil
  • Ayoub, Houssein H
  • Tang, Patrick
  • Coyle, Peter
  • Hasan, Mohammad R
  • Yassine, Hadi M
  • Benslimane, Fatiha M
  • Al-Khatib, Hebah A
  • Al-Kanaani, Zaina
  • Al-Kuwari, Einas
  • Jeremijenko, Andrew
  • Kaleeckal, Anvar Hassan
  • Latif, Ali Nizar
  • Shaik, Riyazuddin Mohammad
  • Abdul-Rahim, Hanan F
  • Nasrallah, Gheyath K
  • Al-Kuwari, Mohamed Ghaith
  • Butt, Adeel A
  • Al-Romaihi, Hamad Eid
  • Al-Khal, Abdullatif
  • Al-Thani, Mohametabd H
  • Bertollini, Roberto

publication date

  • January 27, 2022

Research

keywords

  • 2019-nCoV Vaccine mRNA-1273
  • BNT162 Vaccine
  • COVID-19

Identity

PubMed Central ID

  • PMC8795418

Scopus Document Identifier

  • 85123815213

Digital Object Identifier (DOI)

  • 10.1016/j.eclinm.2020.100651

PubMed ID

  • 35087035

Additional Document Info

volume

  • 13

issue

  • 1