AUTHOR=Søraas Arne , Grødeland Gunnveig , Granerud Beathe Kiland , Ueland Thor , Lind Andreas , Fevang Børre , Murphy Sarah L. , Huse Camilla , Nygaard Anders Benteson , Steffensen Anne Katrine , al-Baldawi Huda , Holberg-Petersen Mona , Andresen Lise Lima , Ågnes Camilla , Ranheim Trine , Schanke Ylva , Istre Mette , Dahl John Arne , Chopra Adity , Dudman Susanne , Kaarbø Mari , Andersen Jan Terje , Vaage Eline Benno , Tran Trung The , Vaage John Torgils , Michelsen Annika E. , Müller Fredrik , Aukrust Pål , Halvorsen Bente , Dahl Tuva B. , Holter Jan Cato , Lund-Johansen Fridtjof 

TITLE=Breakthrough infections with the omicron and delta variants of SARS-CoV-2 result in similar re-activation of vaccine-induced immunity

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.964525

DOI=10.3389/fimmu.2022.964525

ISSN=1664-3224

ABSTRACT=Background: Results showing that sera from double vaccinated individuals have minimal neutralizing activity against Omicron have been interpreted as indicating the need for a third vaccine dose for protection. However, there is little information about early immune responses to Omicron infection in double vaccinated individuals.

Methods: We measured inflammatory mediators, antibodies to the SARS-CoV-2 spike and nucleocapsid proteins, and spike peptide-induced release of interferon gamma in whole blood in 52 double-vaccinated individuals infected with Omicron, in 18 infected with Delta, and in 14 healthy controls. The median time points for the first and second samples were 7 and 14 days after symptom onset, respectively.

Findings: Infection with Omicron or Delta led to a rapid and similar increase in antibodies to the receptor-binding domain (RBD) of Omicron protein and spike peptide-induced interferon gamma in whole blood. Both the Omicron- and the Delta-infected patients had a mild and transient increase in inflammatory parameters. 

Interpretation: The results suggest that two vaccine doses are sufficient to mount a rapid and potent immune response upon infection in healthy individuals with the Omicron variant.

Funding: The study was funded by the Oslo University Hospital, and by grants from The Coalition for Epidemic Preparedness Innovations, Research Council of Norway (no 312780, 324272), South-Eastern Norway Regional Health Authority (no 2019067, 2021071, 10357, 2021047, 33612, 2021087, 2017092), EU Horizon 2020 grant no 848099, a philantropic donation from Vivaldi Invest A/S owned by Jon Stephenson von Tetzchner, and The European Virus Archive Global.