Covid-19: Where are we on immunity and vaccines?BMJ 2020; 370 doi: https://doi.org/10.1136/bmj.m3096 (Published 05 August 2020) Cite this as: BMJ 2020;370:m3096
- Elisabeth Mahase
- The BMJ
Do the recent vaccine papers tell us anything new?
There was a flurry of excitement last month when two new papers published in the Lancet outlined the early findings from two SARS-CoV-2 vaccine trials.
The first came from the University of Oxford1 and reported that, in a phase I/II trial involving just over 1000 healthy adults (543 given the vaccine, 534 given the meningococcal conjugate vaccine as a control), the vaccine candidate induced strong antibody and T cell immune responses (up to day 56). They reported no serious adverse events.
The ChAdOx1 nCoV-19 vaccine uses an adenovirus vaccine vector and the genetic sequence for the SARS-CoV-2 spike protein. After the vaccine has been administered the spike protein is produced, which primes the immune system to recognise and attack the virus if the vaccinated person is infected in the future. The researchers, led by Sarah Gilbert, professor of vaccinology, have teamed up with AstraZeneca and have already begun phase III trials in England to determine efficacy, as well as in South Africa and Brazil. A US trial should begin later this year.2
The second paper came from researchers in China, who tested their non-replicating adenovirus type-5 vectored vaccine (Ad5-nCoV) on 382 participants (who received either a high or low dose, while 126 people received a placebo).3 This vaccine candidate, developed with CanSino Biologics, uses a weakened human common cold virus to deliver genetic material that codes for …