Offline: Preparing for a vaccine against COVID-19

The Lancet
Jul 25, 2020 Volume 396 Number 10246 p213-290, e6-e11


Offline: Preparing for a vaccine against COVID-19
Richard Horton
The results of two randomised trials reported this week in The Lancet give great encouragement to the view that a vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can be produced within the next 18 months. There are no guarantees. But the evidence is hopeful. Pedro Folegatti and colleagues from The Jenner Institute at the University of Oxford used a chimpanzee adenovirus viral vector expressing SARS-CoV-2 spike protein to create a vaccine given by a single intramuscular injection. The ChAdOx1 nCoV-19 vaccine, tested in five trial sites in the UK, was safe and well tolerated, and led to striking findings of both humoral and cellular immune responses. This candidate vaccine is now undergoing phase 3 trials in Brazil, South Africa, and the UK. Feng-Cai Zhu and colleagues completed a single-centre phase 2 randomised trial in Wuhan, China, using a recombinant adenovirus type-5-vectored COVID-19 vaccine. They found rapid onset of an immune response within 14 days, with evidence of humoral and cellular immune responses by day 28. This vaccine was also safe and well tolerated. There were signs that it produced a poorer immune response in older recipients. As the vaccine enters phase 3 trials, a second dose will be considered for this group to boost their immunity. These results are unquestionable breakthroughs in the global response to the COVID-19 pandemic.