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Home » Vaccines » “More ‘real-world’ efficacy studies are needed”

Adrian Wildfire

Scientific Director, SGS Life Sciences

Leading vaccine expert Adrian Wildfire outlines the changes needed to ensure more vaccines coming into the market do ‘what they say on the tin’.

Discussing the immediate need for more effective vaccines – designed to combat seasonal epidemics like influenza and the SARS-CoV-2 epidemic currently circling the globe – has perhaps never been so timely.

In some respects, this was seen before with the SARS outbreak in 2003 and Swine Flu in 2009/10 – yet vaccine efficacy for influenza has been in steady decline since 2005.

“There is a long-standing issue with seasonal epidemic influenza, the biggest threat to human health on a yearly basis,” notes Adrian Wildfire, SGS Life Sciences’ Scientific Director.

“It’s concerning that ourvaccine industry is struggling to provide a product which gives the population the necessary protective index. More research should happen at the pre-clinical and early clinical modelling.”

“There is only 15%* efficacy for some strains of influenza, an all-time low and an indication of where the industry is at currently.”

Why are vaccines failing, you may ask? The picture as to why our current vaccines simply aren’t  improving fast enough is complex.”

Vital measures of ‘real-world’ efficacy are often overlooked. Can the vaccine block transmission by reducing shedding and, for those infected, do they remain well?

There are 2 ways of measuring vaccine success:

  • does the patient get better?
  • does the virus disappear?

“You want the pathogen health to be as bad as possible and the host health to be as good as possible – you can often best measure these in human challenge studies.”

Vaccination programmes, should be measured on whether the numbers of people catching the virus are going down and whether patient symptomology decreases across the board.

“It’s known that once an infected person is ill enough to require admitting to hospital, the chances of severe disease and death climbs dramatically. Measuring recovery rates here is not very representative of a vaccine’s efficacy.

In the SGS Clinical Patient Unit, we model lots of new approaches to tackle infectious diseases. We can measure endpoints for both viral and host efficacy in healthy individuals who do not have co-infections or co-morbidities, and provide a clearer picture of likely outcomes in the community. New ways of delivering vaccines to patients, such as crystal patches attached to the skin, may well enable inoculation en masse to be simplified in future, and are easy to model in controlled environments, such as in human challenges studies (CHIM) where participants are deliberately exposed to infectious agents in order to directly measure effects.”

Modelling in humans to judge the value of interventions is essential prior to late phase studies, as animal models may provide a poor prediction of efficacy in the field. Our CHIM unit has modelled this recently in two studies and provided solid evidence for candidate choices.”

Vaccines development is a long process, and for the safety of the population, no step should be avoided, and clinical trials remain one of the vital components to ensure vaccine safety and efficacy.


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