COVID-19 vaccine trials do not assess severe disease
Thursday October 22nd 2020
Mass vaccination could be introduced against COVID-19 without any evidence indicating it could save lives, an expert warns today.
None
of the current COVID-19 trials are designed to tell us if they can save
lives or reduce hospitalisations, according to the report in The BMJ.
Associate editor Peter Doshi says although several vaccine trials are now in phase 3 stage, those for which details have been released are evaluating only the mild version of the disease.
Vaccine manufacturers have done little to dispel the notion that severe COVID-19 was what was being assessed, he argues.
He said in the Moderna trial, hospitalisations are described as a “key secondary endpoint” in statements to the media - but its chief medical officer Dr Tal Zaks told The BMJ that their trial lacks adequate statistical power to assess that endpoint.
Because most people with symptomatic COVID-19 infections experience only mild symptoms, even trials involving 30,000 or more patients would turn up relatively few cases of severe disease, writes Doshi.
“Hospitalisations and deaths from COVID-19 are simply too uncommon in the population being studied for an effective vaccine to demonstrate statistically significant differences in a trial of 30,000 people,” he adds. “The same is true regarding whether it can save lives or prevent transmission: the trials are not designed to find out.”
Dr Zaks says that Moderna’s trial will not demonstrate prevention of hospitalisation because the size and duration of the trial would have to be increased to collect the necessary data.
He says the trial, like that of Pfizer and Johnson and Johnson, aims to detect a relative risk reduction of at least 30% in participants developing lab-confirmed COVID-19, consistent with FDA and international guidance.
Dr Zaks says the COVID-19 vaccine trial is similar influenza vaccines in that they protect against severe disease better than mild disease.
“To Moderna, it’s the same for COVID-19: if their vaccine is shown to reduce symptomatic COVID-19, they will feel confident it also protects against serious outcomes,” Doshi writes.
However, Doshi points out that few of the current vaccine trials are designed to find out if there is a benefit in the elderly and says if the frail elderly are not enrolled into vaccine trials in sufficient numbers “there can be little basis for assuming any benefit against hospitalisation or mortality.”
He asks why Doshi why children, immunocompromised people and pregnant women have largely been excluded; if the right primary endpoint has been chosen; if safety is being adequately evaluated; and if gaps in our understanding of how our immune system responds to COVID-19 are being addressed.
“The COVID-19 vaccine trials may not have been designed with our input, but it is not too late to have our say and adjust their course. With stakes this high, we need all eyes on deck,” he argues.
Doshi P. Will COVID-19 vaccines save lives? Current trials are not designed to tell us. The BMJ 22 October 2020
https://www.bmj.com/content/371/bmj.m4037
* Photo above: New art exhibition at Addenbrooke's Hospital, Cambridge, features the work of staff, patients and the public.
Tags: Flu & Viruses | Pharmaceuticals | World Health
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