Refereed journal article or data article (A1)

Strong Neutralizing Antibody Responses to SARS-CoV-2 Variants Following a Single Vaccine Dose in Subjects With Previous SARS-CoV-2 Infection

List of Authors: Ekström Nina, Haveri Anu, Solastie Anna, Virta,Camilla, Österlund Pamela, Nohynek Hanna, Nieminen Tuomo, Ivaska Lauri, Tähtinen Paula A., Lempainen Johanna, Jalkanen Pinja, Julkunen Ilkka, Palmu Arto A., Melin Merit


Publication year: 2022

Journal: Open Forum Infectious Diseases


Journal acronym: OPEN FORUM INFECT DI

Volume number: 9

Issue number: 12

Number of pages: 9

ISSN: 2328-8957

eISSN: 2328-8957



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Background: Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection primes the immune system; thus individuals who have recovered from infection have enhanced immune responses to subsequent vaccination (hybrid immunity). However, it remains unclear how well hybrid immunity induced by severe or mild infection can cross-neutralize emerging variants. We aimed to compare the strength and breadth of antibody responses in vaccinated recovered and uninfected subjects.

Methods: We measured spike-specific immunoglobulin (Ig)G and neutralizing antibodies (NAbs) from vaccinated subjects including 320 with hybrid immunity and 20 without previous infection. From 29 subjects with a previous severe or mild infection, we also measured NAb responses against Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2), and Omicron (B.1.1.529/BA.1) variants following vaccination.

Results: A single vaccine dose induced 2-fold higher anti-spike IgG concentrations and up to 4-fold higher neutralizing potency of antibodies in subjects with a previous infection compared with vaccinated subjects without a previous infection. Hybrid immunity was more enhanced after a severe than a mild infection, with sequentially decreasing NAb titers against Alpha, Beta, Delta, and Omicron variants. We found similar IgG concentrations in subjects with a previous infection after 1 or 2 vaccine doses.

Conclusions: Hybrid immunity induced strong IgG responses, particularly after severe infection. However, the NAb titers were low against heterologous variants, especially against Omicron.

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Last updated on 2023-17-03 at 15:58