Consultants define key challenges for assessing medical efficacy of COVID-19 vaccines

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Collaboration and standardized approaches to assessing different vaccine efficacy endpoints are key to meaningful comparison of different COVID-19 vaccine candidates to ensure the most effective vaccines are used, say authors of an opinion-based review of the evidence published in The Lancet for infectious diseases.

A vaccine candidate for SARS-CoV-2 could work against infection, disease, or transmission, and a vaccine that can reduce any of these elements could help fight the COVID-19 pandemic. In their essay, the authors highlight the key challenges to assessing the effectiveness of potential COVID-19 vaccines in order to gain insight into the seemingly simple question, “Does this COVID-19 vaccine work?”

The author of the review, Dr. Susanne Hodgson, University of Oxford, UK, said: “It is unlikely that we will see a single vaccine winner in the race against COVID-19. Different technologies bring different benefits that are relevant in different situations. In addition, there will likely be problems, at least.” To manufacture and supply a single vaccine initially on the scale required. A standardized approach to measuring the success of vaccines in clinical trials will be important in order to make meaningful comparisons and effective candidates can be suggested for wider use. “

There are currently 44 candidates in clinical evaluation and an additional 154 in preclinical development, reflecting a range of vaccine technologies. The authors argue that, in order to compare efficacy between these and future candidates, it is important that standardized, quantifiable endpoints are applied to clinical trials of COVID-19 vaccines, and that their limits and risk of bias are understood.

The authors also highlight another challenge: assessing the effectiveness of vaccine candidates in protecting against serious illness and death from SARS-COV-2 infection. They argue that long-term monitoring of recipients of COVID-19 vaccine candidates will be important both to assess efficacy against serious illness and mortality, and to ensure ongoing vaccine safety assessment.

The co-author Dr. Kate Emary of Oxford University, UK, says, “To see if a vaccine protects against severe COVID-19 disease, a clinical study needs to show that people who have been vaccinated with a have significantly fewer cases of serious illness COVID-19 vaccine compared to people who weren’t. However, only a small fraction of those infected with SARS-CoV-2 will develop serious illness, which means an extremely large number of volunteers will be needed in a clinical trial to be enough cases to have a reliable measure of the vaccine’s effectiveness. This means that we will likely not know whether a vaccine will protect against serious disease until it has been used and given to a large population. “

The authors also discuss controlled human infection studies (challenge studies), as they may offer a way to measure the effectiveness of the vaccine if SARS-CoV-2 transmission in the community declines. They argue that while these studies can be the only means of quickly assessing the effectiveness of a vaccine, the relationship between effectiveness in younger people in challenge studies and in older and at-risk populations after vaccine use remains unclear.

They conclude that, in line with the development of novel medical interventions, particularly in this context, it is important to critically evaluate the efficacy results of a SARS-CoV-2 vaccine with scientific accuracy in order to understand their generalizability and clinical significance. They note that some countries may only use COVID-19 vaccines based on safety and immunogenicity data, but the goal of vaccine development is to provide direct evidence of the vaccine’s effectiveness in protecting humans from SARS-CoV-2 infections and – Preserving diseases so that they can be produced by effective vaccines can be selectively scaled up.

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More information:
Susanne H. Hodgson et al., What Makes an Effective COVID-19 Vaccine? An overview of the challenges in evaluating the clinical effectiveness of vaccines against SARS-CoV-2, The Lancet Infectious Diseases (2020). DOI: 10.1016 / S1473-3099 (20) 30773-8

Quote: Experts outline key challenges for evaluating the clinical effectiveness of COVID-19 vaccines (2020, October 28), which will be posted on October 28, 2020 at https://medicalxpress.com/news/2020-10-experts-outline -key-clinical-efficacy.html

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