Are we close to developing a variant-proof Covid-19 vaccine?

Efforts to develop a “holy grail” vaccine that would be effective against all future Covid variants are under way but it could be years until such a jab is ready for widespread use.

Although new Covid vaccines can now be developed within weeks to protect against an emerging variant, scientists hope to develop a single vaccine that would work against any conceivable mutation of Covid-19.

The first wave of vaccines were designed to neutralise the original viral strain, originally identified in Wuhan. Scientists are now working to develop a jab that would offer long-term immunity, whatever new variants come along.

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However, how quickly they can achieve this is another question. For generations, scientists have struggled in vain to create a broadly protective vaccine against mutations of influenza.

Trials for a “variant-proof” booster vaccine began in Manchester last year. Bolton-based couple Andrew and Helen Clarke, aged 63 and 64 respectively at the time, were the first trial participants to receive the new jab

The Coalition for Epidemic Preparedness Innovations (CEPI) has launched a $200m research programme to explore vaccines that provide broad protection against future variants, said Vaccines Today in December.

One promising jab in development with UK-based biotech company DIOSynVax, headed by University of Cambridge professor Jonathan Heeney, is set to receive up to £32m in funding from CEPI, The Times reported.

It is one of several potential jabs that seeks to “target parts of the virus that are less likely to mutate”, the paper said. If Heeney’s team can identify “immutable” parts of the virus, it means it would be plausible that a vaccine “could protect not only against variants but also against new and emerging coronaviruses in the future”.

The vaccine uses “different technology” to other leading jabs. Previous vaccines have introduced the coronavirus spike protein into the body in the hope that we learn to “recognise” the spike protein of the virus and fight it off. But this method “incentivises” the virus to evolve to evade protection by changing its spike.

“All the vaccines we are still using now are based on the Wuhan sequence from January 2020,” said Heeney. “No wonder we are having to boost and boost and boost, because we are losing efficacy as the virus moves away from that sequence.”

By using a “different design of protein” DIOSynVax hopes its vaccine can be used to “provide variant-proof protection, but also potentially be kept ready to use in the event of another coronavirus pandemic”, said The Times. It could also possibly be delivered through using a “tweaked” Pfizer or Oxford vaccine platform.

CBS News reported last month that T-cells generated as part of the body's natural immune response to the common cold may provide a breakthrough. Researchers at Imperial College London said a study could help scientists create vaccines that remain more effective against new variants of the coronavirus.

They found that 26 people who were exposed to Covid-19 but did not fall ill had significantly higher cross-reactive T-cells, generated by previous common colds, than those who did become ill with Covid.

“The fact that (the T-cells) can attack the internal proteins of each of these related viruses [COVID-19 variants] means that they give what’s called a broad cross-protection,” Professor Aljit Lalvani said. “That’s in sharp contrast to the surface spike protein, which is the target of antibodies induced by [current] vaccines.”

He said the study’s results are “a definitive green light” to develop a “T-cell inducing vaccine to internal core proteins, which should protect against current and future variants”.

Meanwhile, across the Atlantic, the US military is also testing a vaccine designed to protect against all variants, reported Quartz.

The Spike Ferritin Nanoparticle (SpFN) vaccine was successfully tested on animals last year and phase one trials had positive results that are under review, said one of the team. Next, it will undergo phase two and phase three trials where researchers can determine its efficacy.

Elsewhere in the US, Barton Haynes, director of the Human Vaccine Institute at Duke University School of Medicine, and his team are working on a vaccine that triggers neutralising antibodies and other immune responses to all the Sars-Cov-2 variants to date. Haynes hopes it will also work against variants that appear in the near future.

However, a variant-proof jab is not expected any time soon. Cepi’s aim is to have proof of concept for such a jab “in the 2023 timeframe”. Melanie Saville, director of vaccine research and development, told the FT it would then take another year or two to be licensed for use.

Therefore, for a truly protective vaccine, “we’re really looking in the timeframe of 2024 to 2025… so it is a long haul”, she added. Anthony Fauci, US president Joe Biden’s chief medical adviser, agreed that it will take a while. “You’re not going to hit a home run the first time up, that’s for sure,” he said.