Safety and immunogenicity of an MF59-adjuvanted spike glycoprotein-clamp vaccine for SARS-CoV-2: a randomised, double-blind, placebo-controlled, phase 1 trial

SPS commentary:

The researchers note that interference with rapid HIV diagnostic tests is a possible barrier to widespread use and highlights the criticality of potential non-spike directed immunogenicity during vaccine development. Studies are ongoing with alternative molecular clamp trimerisation domains to ameliorate this response.

Also published in this issue of the journal are the results of an interim analysis of the first-in-human evaluation of an adjuvanted recombinant protein vaccine against SARS-CoV-2, CoV2 preS dTM (n=441), which found that although the vaccine raised antibodies capable of neutralising wild-type SARS-CoV-2 strains in vitro, it had suboptimal immunogenicity.

According to a commentary, it is not unusual for vaccine development programmes to encounter difficulties, or have a need to revisit the vaccine design or dosing regimen. Importantly, both of these trials have enabled the identification of those aspects of the vaccine composition or production process that require optimisation, enabling product development to resume. It notes that when the world requires vaccines against SARS-CoV-2, diversity in technologies used for production is beneficial, as the likelihood of a limited raw material resource negatively affecting vaccine supply will be reduced, and more existing manufacturing facilities could be brought into use. It adds that although mRNA, adenoviral-vectored, nanoparticle, and inactivated vaccines are now in widespread use, booster doses will probably be required in the future to maintain immunity, and recombinant protein vaccines are known to be effective at boosting pre-existing responses. It suggests that the difficulties ahead might therefore be reduced for these recombinant protein vaccines, which could have an important role in maintaining immunity against SARS-CoV-2.