LNSLNS

We thank Dr. Seydel for presenting this interesting approach which was evaluated in a subgroup of the pivotal study that led to approval of the AstraZeneca vaccine. Unfortunately, the group which received an initial lower dose of the vaccine only included 1396 persons; thus, the difference in efficacy with regard to symptomatic SARS-CoV2 infections just missed the significance threshold (p = 0.050) (1). In addition, since the interval between the administration of the first and second dose was longer in the group with reduced initial dose, it was not possible to differentiate between a dose effect and the known effect of improved vaccine protection by a longer interval between two doses of AstraZeneca vaccine.

Ultimately, the approach of using different doses for the first versus the second administration of the vaccine was not taken further, as this strategy would create logistic challenges in large vaccination campaigns. Thus, there is still a lack of larger-scale studies which are needed to reliably demonstrate adequate (or even greater) efficacy.

DOI: 10.3238/arztebl.m2021.0292

Malte Ziemann, Siegfried Görg
Institut für Transfusionsmedizin
Universitätsklinikum Schleswig-Holstein, Lübeck, Germany
malte.ziemann@uksh.de

Conflict of interest
The authors of both contributions declare no conflict of interest.

1.
Voysey M, Costa Clemens SA, Madhi SA, et al.: Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. Lancet 2021; 397: 881–91 CrossRef
2.
Ziemann M, Görg S: Inability to work after corona vaccination in medical staff. Dtsch Arztebl Int 2021; 118: 298–9 VOLLTEXT
1.Voysey M, Costa Clemens SA, Madhi SA, et al.: Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. Lancet 2021; 397: 881–91 CrossRef
2.Ziemann M, Görg S: Inability to work after corona vaccination in medical staff. Dtsch Arztebl Int 2021; 118: 298–9 VOLLTEXT

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