Details

Autor(en) / Beteiligte

• Ntoumi, Francine
• Kremsner, Peter G

Titel

Vaccination with fractional doses: promise or illusion?

Ist Teil von

• The Lancet infectious diseases, 2022-09, Vol.22 (9), p.1258-1259

Ort / Verlag

London: Elsevier Ltd

Erscheinungsjahr

2022

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• The study design of this clinical trial was based on findings from a phase 2a controlled human malaria infection (CHMI) study assessing vaccine efficacy in adults,2 and from a study evaluating the effect of a change in the vaccine regimen on the quality of antibody responses.3 The phase 2a CHMI studies in malaria-naive adults showed that a regimen containing a delayed third or fourth fractional dose, or both, of RTS,S confers numerically increased protection against malaria compared with the standard RTS,S regimens upon challenge. [...]although Samuels and colleagues aimed to show a meaningful difference between the regimens containing the fractionated doses compared with the standard regimen, statistically there was no difference in efficacy between the different regimens in the CHMI studies or in the current trial in African children. The real immune response history of children cannot be easily assessed with simple antibody measurements but is rather more complex.4 CHMI is done by direct venous inoculation of 3200 purified,5 cryopreserved, fully infectious Plasmodium falciparum sporozoites and has become a gold standard for assessing vaccine candidates, drugs, and naturally acquired immunity.