May 17, 2022

expert reaction to study looking at mRNA and vector vaccines against variants of concern

A study published in PLOS Medicine looks at antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines.

Prof Penny Ward, Independent Pharmaceutical Physician, and Visiting Professor in Pharmaceutical Medicine at King’s College London, said:

“A study today from the Netherlands exploring binding and neutralising antibody titres following use of various COVID vaccines in the healthcare workforce at the same institution demonstrates once more that antibody titres following the viral vector vaccines tend to be lower than following mRNA vaccines. This has been reported previously and comes as no great surprise. The second observation suggests that the antiviral effect of viral vector vaccines vs virus variants may also be lower than following vaccination with mRNA vaccines has also been suggested by other groups, although, as the authors observe, protection against severe disease following infection/illness caused by these variants is nonetheless still significant. Protective effects of vaccination type, dose and regimen are still being explored for the various vaccines currently in clinical use but based on cumulative experience it seems clear that none of the vaccines successfully prevents infection, mRNA vaccines are more effective vs symptomatic illness but all vaccines protect to a similar extent against hospitalisation/death from COVID notwithstanding the differences in antibody level observed following clinical use. At this point and with the wealth of data available across the many many studies completed and reported, it would be very helpful to pool the data and propose correlates of protection which can be used to qualify vaccines for the future. Indeed it would also be helpful to switch now to investigating the benefit of vaccination with revised strain types – as seems likely to be needed in future – and to consider from this whether immunecorrelates and duration of protection are likely to improve as a result.”

‘Antibody responses against SARS-CoV-2 variants induced by four different SARS-CoV-2 vaccines in health care workers in the Netherlands: A prospective cohort study’ by Marit J. van Gils et al. was published in PLOS Medicine at 19:00 UK time on Tuesday 17 May 2022.

DOI: 10.1371/journal.pmed.1003991

Declared interests

Prof Penny Ward: “I am semi-retired, but I am owner/Director of PWG Consulting (Biopharma) Ltd a consulting firm advising companies on drug and device development. Between December 2016 and July 2019 I served as Chief Medical Officer of Virion Biotherapeutics Ltd, a company developing antiviral treatments for respiratory viral diseases. Previous employee of Roche, makers of tocilizumab (anti IL6 antibody) and CMO of Novimmune, makers of empalumab (anti IFN gamma antibody).”