Shot in the dark: Why does the flu vaccine vary and is there an alternative approach?
As we embark on a difficult flu season, I look at why infection rates vary so much year on year and the potential universal vaccine one company is progressing through the clinical development stages.
As I sit in the office surrounded by coughing and spluttering, sneezing and wheezing, it came as no surprise to me to find out there has been a surge in flu cases this year. The signs and symptoms of a difficult season ahead for the northern hemisphere became clear after reports landed about the experiences of Australia and New Zealand where hospitals had struggled to cope.
But, why, in this day and age of medical innovation, are we still encountering such variances in infection rates year to year from a seasonal virus and why can the vaccines’ efficacy be such a ‘shot in the dark’?
Part of the reasoning as to why the efficacy of the flu vaccine varies is that the virus itself keeps mutating and there are multiple strains in circulation simultaneously. However, another truth behind the variability is the science of how the flu vaccination is created, which some have described as ‘imprecise’.
Currently, vaccines to combat seasonal flu are created from viral strains that are deemed to be the most likely ones to be in circulation by the World Health Organisation (WHO) — this assessment is performed in February for the northern hemisphere and September for the southern hemisphere. Production of the vaccine is then started a month after the announcement so that it can be ready for the general population just before the winter season begins.
Obviously, this approach means that there is an element of uncertainty about efficacy. If WHO predicts the correct strains then most people who receive the vaccination will be protected. However, if the strains are incorrect, then the proportion of people protected becomes much lower.
So, if there is always an amount of uncertainty with this method, is there another approach that could be used in the creation of a seasonal flu vaccine?
Well, an Oxford University spinout company, Vaccitech, says ‘yes there is’! It has recently secured funding from multiple investors (including the venture capital arm of Google parent company Alphabet, GV) and has already begun its two-year Phase II clinical trial of a universal flu vaccine.1
This universal flu vaccine, which has already been successfully tested for safety in 145 people, is unique from the traditional versions as it uses proteins that are housed within the core of the virus to stimulate the immune system to boost influenza-specific T-cells rather than antibodies. According to the company,2 previous research has demonstrated that these T-cells can help the body to fight more than one type of influenza virus, which in turn should mean more people are protected after receiving the vaccine.
More than 2,000 people aged 65 years and older have been registered at six general practices to take part in the trial over the course of the winter season. Those who participate will be randomised to either receive the current vaccine in addition to a placebo jab or the new universal flu shot. It is expected to be completed in 2019.
“If we get positive data that shows we can affect rates of hospitalisation and illness with influenza then there is no question in my mind that a partner would take this on,” said Vaccitech chief executive, Tom Evans when speaking with Reuters.3 “This could be a game-changer in a very competitive market.”
Although this is not the only universal vaccine for influenza out there, it is the first one that has made it into the second phase of clinical study. So, as we brace ourselves for a rough flu season, this exciting progression offers some hope for a future where less injections are needed and more people can rest easy with greater protection against the virus.
For now, stay healthy,
Felicity
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