Alliance for Pandemic Preparedness

May 12, 2021

Antibody Responses After a Single Dose of ChAdOx1 NCoV-19 Vaccine in Healthcare Workers Previously Infected with SARS-CoV-2

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  • [Pre-print, not peer-reviewed] Sera of participants with detectable spike antibodies produced by natural infection had higher levels of anti-SARS-CoV-2 spike IgG antibodies against the wild-type strain and variants of concern (B.1.1.7, B.1351, and P.1) at least one week after a single dose of the Oxford-Astrazeneca vaccine (n=83) compared to sera from a mixed group of seronegative and seropositive participants at least 2 weeks after the second dose of the Pfizer-BioNTech vaccine (n=149; 36 with previous infection and 113 without). Similarly, levels of pseudo-neutralizing spike-ACE2 blocking antibodies against the wild-type strain and variants of concern were also higher among seropositive individuals with a single dose of the Oxford-Astrazeneca vaccine compared to a mixed group of seronegative and seropositive vaccine recipients after 2 doses of the Pfizer-BioNTech vaccine. [editorial note: Previous studies have clearly established that seropositive individuals receiving mRNA vaccines have much higher antibody titers after vaccination compared to seronegative individuals receiving the same vaccine. Since the authors of this preprint analyzed a combined group of seronegative and seropositive individuals receiving an mRNA vaccine, the editors advise caution in interpreting the data from this preprint].

Havervall et al. (May 11, 2021). Antibody Responses After a Single Dose of ChAdOx1 NCoV-19 Vaccine in Healthcare Workers Previously Infected with SARS-CoV-2. Pre-print downloaded May 12 from https://doi.org/10.1101/2021.05.08.21256866