Coronavirus: Threat is rising of diseases passed from animals, warns Oxford vaccine professor

Growing population density, increased international travel and deforestation are believed to be driving the spread of zoonotic-based infections

Researchers think coronavirus jumped from bats to humans via an intermediate animal (AFP/Getty)

The professor behind the Oxford coronavirus vaccine has warned of the rising risk of outbreaks of diseases that pass from animals to humans.

Sarah Gilbert, who is leading the bid to find a jab that gives immunity to coronavirus, believes that the spread of zoonotic diseases has become more likely due to our lifestyles.

In particular, growing population density, increased international travel and deforestation are blamed.

The origins of the coronavirus pathogen remain a mystery but most researchers believe that the virus emerged in bats before jumping across into the human population via another animal.

Other diseases that have spread across the world recently, including Ebola, Sars and the West Nile virus, have also originated in animals – although Covid-19 has proved the most contagious.

The Independent is calling for an international effort to clamp down on the illegal trade of wild animals, which remains one of the greatest threats to future biodiversity. The paper’s Stop The Illegal Wildlife Trade campaign has been backed by conservation charities including Animals Asia, World Animal Protection US and Space for Giants.

According to the World Health Organisation, around a billion cases of illness and millions of deaths occur every year from zoonoses, or zoonotic diseases, while some 60 per cent of emerging infectious diseases that are reported globally have jumped from animals to humans.

The threat posed by these diseases, Professor Gilbert says, is unlikely to diminish in the future as the world becomes more and more globalised.

“Because of the way things have been going in the world, it’s more likely we’ll have zoonotic infections causing outbreaks in the future,” the professor of vaccinology at Oxford University’s Jenner Institute told The Independent.

“Greater population density, greater travel, deforestation – all of these things make it more likely that these outbreaks will happen and then something will spread.”

Last month, experts from the United Nations similarly warned that the number of zoonotic diseases will continue to increase unless action is taken to protect wildlife and preserve the environment.

According to a report by the UN’s Environment Programme and the International Livestock Research Institute, the transfer of pathogens from animals to humans is driven by the deterioration of the natural environment – through land degradation, wildlife exploitation, resource extraction and climate change.

Beyond the threat posed by these diseases, Professor Gilbert, who was involved in the development and testing of a universal flu vaccine, also believes there will be a future outbreak of another potent influenza strain, similar to that seen during the 2017-18 season.

In the US, influenza killed about 80,000 people throughout the 2017-2018 winter, according to the Centres for Disease Control and Prevention, making it one of the deadliest outbreaks in decades.

“There will be another flu pandemic in the future,” said Professor Gilbert. “It will come around again, [but] we don’t know which subtype of flu it will be.

“I was working on a universal flu vaccine that would work against all the types of flu, whether it was H1N1, H3N3, [or] H7N7.” The creation of this one-size-fits-all vaccine, she adds, means “we wouldn’t need to know in advance” about the viral subtype.

There has so far been no approved universal flu vaccine for general use.

“[With] flu there has been several pandemics every century as far back as we can measure things, and there are so many different flu viruses out there – so we can’t ever eradicate flu.

“We’ve eradicated small pox, as it doesn’t exist in animals. We’ve come very close to eradicating polio – a very good result this week: no polio in Africa. That’s huge.

“There are other diseases like measles that could in theory be eradicated as there’s not an animal reservoir. But that doesn’t apply to flu, and flu is in lots of migratory wild birds and we can’t get rid of that reservoir.

“It will continue to start to infect people and then there’ll be another pandemic with a different type of flu we haven’t seen before.”

Professor Gilbert and her team announced this week that trial data for the Oxford vaccine candidate could be presented to regulators soon.

If the latest results from the phase three trials demonstrate high levels of efficacy, and licensing approval is subsequently granted, there is hope that the vaccine, called AZD1222, could be available by the end of the year.

AstraZeneca, which has partnered with Oxford University to manufacture the vaccine, has committed to producing two billion doses by next summer.

Currently, the vaccine is being trialled in tens of thousands of volunteers in the UK, South Africa, Brazil and the US. Other vaccines in development have entered into the same stage, and Professor Gilbert is confident that many of these will deliver positive results.

“I think there’s a very good chance that many of these vaccines will prove effective,” she said. “We’ve seen good levels of neutralising antibodies, we’re seeing strong T cell responses from some of them.

“If this works, other vaccines will also work. We expect there to be multiple vaccines.

“And there are veterinary vaccines against coronaviruses. There are two licensed ones that work: one for a bovine coronavirus and one against an avian coronavirus – and they are widely used. So you can vaccinate against coronaviruses, it’s just that we haven’t done it before in humans.

“So from first principles there’s a very good possibility that we will have vaccines against the coronavirus.

“And if we can make two billion doses of this vaccine and then other manufacturers step up as well, that’s the best solution.”

However, Professor Gilbert admitted that, at this stage, it’s “difficult” to establish how long protection triggered by AZD1222 will last for, and what level of immunity will be achieved.