Leaves outside our office windows in St. James’s are starting to turn colourful. Fall is coming, and so is the second wave of the SARS-CoV-2 virus which has resurged in recent weeks in many countries. Once again, our focus has turned to vaccines for solutions to liberate us from being hostages to COVID-19.
Back in July, we wrote an insight entitled The Race for a COVID-19 Vaccine. Significant progress has been made by scientists since then.
In this document, we provide our latest insights on the status of vaccine development, the likely timing of vaccines available to us, and how vaccines will be rolled out. We also discuss the advances in therapeutic treatment of COVID, and look at promising therapies that can be used to reduce the severity of the disease and thus act as a critical bridge before vaccines arrive. Finally, we provide our perspective on a roadmap for ending the pandemic and returning our lives to normality.
Vaccines: The Current Status of Vaccine Development
According to the World Health Organisation (WHO), as of September 30, there are 192 vaccine candidates in development, more than 40 in clinical evaluation and 10 in phase three (the last stage of clinical development before approval). In our July insight, we introduced different vaccine technology platforms and the characteristics of each. Amongst the 10 most advanced clinical programmes, four are non-replicating viral vector vaccines, three are inactivated vaccines and two are mRNA vaccines. By developing vaccine candidates using different technology platforms, the world will have more shots on goal to obtain one or more efficacious and safe vaccines.
Most Advanced Vaccine Programmes
In the US and Europe, the three most advanced programmes are from Pfizer/BioNTech, Moderna/NIH and AstraZeneca/Oxford University and all are well into their respective phase III trials. In earlier phase1/2 clinical testing, all three vaccine candidates generated neutralising antibodies and antibody titre at levels equal to or greater than those produced by patients who have recovered from COVID-19. All three vaccine candidates generated a T-cell response which is important for our body to fight the infection. These vaccine candidates were well tolerated, whilst side effects were largely mild and moderate, and were transient.
Regulatory Requirements for Vaccine Approval
Phase III clinical trials are much larger in size and include a greater proportion of older people (age >65) and people with increased risk of complication from COVID-19, as well as more diversity in ethnicity and race. Trials are randomised, double-blind and placebo controlled. The test of efficacy is based on statistical analysis of the number of symptomatic infections that have occurred in the vaccinated arm compared to that in the placebo arms. Infections are confirmed by the positive PCR virus (antigen) test and by at least one or two symptoms of COVID-19. The timing of the trial completion is event driven and based on the number of symptomatic infections. The safety of these trials is monitored continuously by the independent Data and Safety Monitoring Board (DSMB).
The trial design has a number of interim analyses to assess the efficacy. At each interim analysis, DSMB will take a look at the trial efficacy data and will either allow the trial to continue or to stop. The latter happens either on the grounds of safety concerns or of efficacy results — for example, if a trial shows overwhelming efficacy, making it unethical to continue with the trial for people on the placebo arm, or if a trial has little chance of meeting the required efficacy end point.
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