Globally, this flu season has been one of the worst in recent years. In the US, the Centers for Disease Control and Prevention (CDC) has officially declared an epidemic, meanwhile figures from Public Health England (PHE) suggested a sharp rise in flu hospital admissions in the country.

Part of the problem is that a new flu vaccine has to be developed every year, with the World Health Organisation (WHO) identifying the main strains it believes will circulate the Northern Hemisphere the following winter. As the NHS explains, work begins on these vaccines in March and they are made available in the UK from September.

While this means that the flu vaccine should protect patients from the main types of flu that year, it also means that its effectiveness can change every year.

Director of the Worldwide Influenza Centre laboratory in London, Dr John McCauley, told Sky News that this year's vaccine is "considered of moderate effectiveness, which means 30-40% of cases will be avoided among people who have the vaccine."

But work is being undertaken by a UK company to produce the world's first universal flu vaccine. This would stop the need for new flu vaccines being produced every year.

Vaccitech, a private spin-off of Oxford University, has just closed a Series A fundraising round that amounted to a total of GBP20m (EUR22.5m). The round was co-led by GV (the venture capital arm of Google's parent Alphabet Inc), Oxford Sciences Innovation, and Sequoia China, joined by Neptune Ventures.

In addition to this funding, the company has already started a two-year Phase 2 clinical trial investigating its patented universal flu vaccine, MVA-NP+M1. So far, the safety of the vaccine has successfully been tested for across 145 people.

The company is now testing the vaccine's efficacy in a world-first trial involving 862 people aged 65 and older, with researchers estimating this trial will be complete by October 2019. Participants will receive the regular flu vaccine in addition to either the new universal jab or a placebo shot. If the results show the new vaccine increases protection against flu when compared to the annual jab, the vaccine could progress to final Phase 3 trials.

Vaccitech's vaccine differs from current flu shots as it uses proteins found in the core of the virus, as opposed to those on the surface, as they are more stable than the surface proteins. This will then boost T-cells that are already familiar with flu, instead of stimulating antibodies.

Speaking to Reuters, Vaccitech CEO, Tom Evans, commented: "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. This could be a game-changer in a very competitive market."

Evans believes that, if all goes well, the shot could potentially be ready for launch in 2023, although he noted that 2024 or 2025 could be more realistic.

Discussing Google's interest in Vaccitech, GV's general partner, Tom Hulme, said: "Vaccitech's world class team have achieved an incredible amount with relatively little funding to date – the T-cell responses to the company's viral vector platforms are among the highest that have been achieved in man – we look forward to it being applied to tackle multiple human diseases."

Universal flu isn't the only disease on Vaccitech's agenda. The company is also working on creative a vaccine for prostate cancer, investigating Middle East Respiratory Syndrome (MERS), and vaccines for HPV and HBV.