Comparative Effectiveness of Coronavirus Vaccine in Preventing Breakthrough Infections among Vaccinated Persons Infected with Delta and Alpha Variants

Details

• Alternative Title:
  Emerg Infect Dis
• Personal Author:
  Kislaya, Irina ; Rodrigues, Eduardo Freire ; Borges, Vítor ; Gomes, João P. ; Sousa, Carlos ; Almeida, José P. ; Peralta-Santos, André ; Nunes, Baltazar
• Corporate Authors:
  PT-COVID-19 Group2
• Description:
  We developed a case-case study to compare mRNA vaccine effectiveness against Delta versus Alpha coronavirus variants. We used data on 2,097 case-patients with PCR-positive severe acute respiratory syndrome coronavirus 2 infections reported in Portugal during May-July 2021. We estimated the odds of vaccine breakthrough infection in Delta-infected versus Alpha-infected patients by using conditional logistic regression adjusted for age group and sex and matched by the week of diagnosis. We compared reverse-transcription PCR cycle threshold values by vaccination status and variant as an indirect measure of viral load. We found significantly higher odds of vaccine breakthrough infection in Delta-infected patients than in Alpha-infected patients (odds ratio 1.96 [95% CI 1.22-3.14]), suggesting lower effectiveness of the mRNA vaccines in preventing infection with the Delta variant. We estimated lower mean cycle threshold values for the Delta cases (mean difference -2.10 [95% CI -2.74 to -1.47]), suggesting higher infectiousness than the Alpha variant.
• Subjects:
  Alpha Variant Breakthrough Infections Comparative Effectiveness Of Coronavirus Vaccine In Preventing Breakthrough Infections Among Vaccinated Persons Infected With Delta And Alpha Variants Coronavirus Disease Covid-19 Covid-19 Vaccines Delta Variant Humans Mrna Vaccines Portugal Research Respiratory Infections Sars-Cov-2 Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination Vaccine-Preventable Diseases Vaccines, Synthetic Viruses Zoonoses

  More +
• Source:
  Emerg Infect Dis. 2022; 28(2):331-337
• Pubmed ID:
  34876242
• Pubmed Central ID:
  PMC8798697
• Document Type:
  Journal Article
• Volume:
  28
• Issue:
  2
• Collection(s):
  Emerging Infectious Diseases
• Main Document Checksum:
  urn:sha256:81c768a426c50e542b8ca158de967548ebd5168ff64caa80a8f2e8edf852991f
• Download URL:
  https://stacks.cdc.gov/view/cdc/114552/cdc_114552_DS1.pdf
• File Type:
  [PDF - 929.96 KB ]