mRNA Vaccine Effectiveness Against COVID-19 in Healthcare Personnel: A Study from New York City

Strategic Insights -

A new study conducted by researchers at the Memorial Sloan-Kettering Cancer Center has provided valuable insights into the effectiveness of mRNA vaccines against COVID-19 in healthcare personnel in New York City. The retrospective study examined laboratory-confirmed SARS CoV-2 infections among 13,658 healthcare personnel from November 2020 to August 2021, a period that saw the emergence of the B.1.617.2 (Delta) variant.

Key Takeaways:

  • The study found that overall vaccine effectiveness (VE) was 94.5% in the pre-Delta period, with no hospitalizations occurring among vaccinated healthcare personnel.
  • In the Delta-dominant phase, VE declined to 75.6%, but strong vaccine protection against hospitalization was maintained throughout the study period.
  • Whole genome sequencing of 369 isolates in the pre-Delta period revealed no clade bias for variants of concern/variants of interest specific to post-vaccine infections.
  • The study highlights the importance of ongoing vaccination efforts, particularly in high-risk groups such as healthcare personnel, to prevent COVID-19 hospitalizations.
  • The study's findings have significant implications for public health policy and vaccine decision-making in the context of emerging variants and evolving pandemic dynamics.

Statistics:

  • 13,658 healthcare personnel were included in the study, with 12,379 receiving at least one dose of an mRNA vaccine.
  • The pre-Delta period saw 94.5% vaccine effectiveness, with 369 isolates sequenced for genomic analysis.
  • In the Delta-dominant phase, vaccine effectiveness declined to 75.6%, with 17 hospitalizations and 1 death occurring among unvaccinated healthcare personnel.
  • No hospitalizations occurred among vaccinated healthcare personnel throughout the study period.

Sources:

  • Memorial Sloan-Kettering Cancer Center
  • Clinical Infectious Diseases
  • Oxford Univ Press Inc, Journals Dept
  • Mini Kamboj, Memorial Sloan-Kettering Cancer Center, Dept. of Medicine, Infect Dis
  • Elizabeth Robilotti, Anabella Lucca, Tobias M. Hohl, N. Esther Babady, Karissa Whiting, Alexander Solovyov, Benjamin Greenbaum, Venkatraman E. Seshan, Rebecca Guest, Tracy McMillen, Krupa Jani, Deborah Korenstein, Chester Poon, Suzanne Kelson, Kevin Browne, Scott Freeswick, Denis Ruchnewitz, Michael Lassig, and Marta Luksza.