Sheer scale of China’s COVID risk justifies pre-flight testing

I saw Pope Benedict at World Youth Day in Sydney in 2008. I was swept up in the enthusiasm of the young crowd and briefly joined them walking to the gathering. Soon I was called in to help investigate a major respiratory outbreak at a school gymnasium where scores of Catholic youth were sleeping (and coughing), crowded cheek-by-jowl, a half-arm touch apart.

That investigation, led by Sydney University’s Professor Dominic Dwyer, later to be Australia’s only representative on the World Health Organisation investigation of the origins of COVID in China, made fascinating findings: all four variants of influenza were present (A H1, A H3 and the 2 B lineages), indicating a large array of flu viruses had arrived with the pilgrims from around the world and multiplied in a crowded setting.

Up close and personal ... the crowds greeting Pope Benedict XVI at World Youth Day in Sydney in 2008.Credit: AP

Touch is a human need. Australia has just celebrated New Year enthusiastically and intimately, with hugs and kisses, and we are ardently hopeful of a better year in 2023, having adapted to living with COVID with minimal restrictions.

Controversy has arisen, however, with the revelation that Chief Health Officer Paul Kelly is at odds with the federal government he advises. He has questioned the need for its intervention to insist that travellers from China, in particular, are tested for COVID before their departure, a move that I have promoted.

With tens of millions of cases in China, I contend that a new subvariant is almost inevitable. It is in the nature of an RNA virus to mutate and change. So screening could detect and reduce importation of such a variant.

I agree with aspects of Paul Kelly’s position: China currently does not have any known novel subvariants of Omicron while we do have high levels of community immunity to such subvariants. And the trend is towards milder disease, albeit of a more transmissible virus.

Public health decision-making remains complex and contestable, but it is more and better informed by science, including epidemiology, vaccinology, immunology, modelling and machine learning. Predicting the future is very difficult and great minds will differ. Kelly concludes that our risk is low. I agree with the government’s approach in applying an abundance of caution.

But the question becomes whether China should be singled out for this caution. What happened with the 2008 World Youth Day is potentially repeated by every planeload of arrivals that comes to Australia, especially from the northern hemisphere winter – be it China, Europe or the US. Our decision about pre-flight testing of travellers from China alone may miss an influx of new viruses from other countries.

But the difference is the sheer scale. No other country but China could do social experiments on such a huge scale: from a five-year leap forward to a one-child policy, then a zero-COVID approach – newly reversed and replaced by a torrent of disease. Conservative estimates suggest 100 million cases in the past month – ample opportunity for a new subvariant, unknown to Australia, to emerge.

Just over a year ago, the first Omicron variant spread from South Africa around the world in just a few days. A soup of subvariants has since ensued, ones such as BF.7, BQ.1.1 and XBB (extra bad boy!), supplanting earlier varieties through better binding to human cells, immune evasion and increased transmissibility. Australia and China are both rife with similar COVID subvariants, so transmissible that most infections occur through the air as well as by human touch.

And yet human touch remains vital. Because of COVID control measures, elderly vulnerable people have died alone. I was prevented from visiting my dying sister by border restrictions into Queensland. Many families around the world have suffered for the past three years without being able to hug and kiss close and vulnerable relatives.

Humans have always drawn strength from touch. Before the 1800s, monarchs of England and France were thought to be imbued with the healing touch, miraculous physicians who could especially heal TB infection of glands in the neck (called scrofula). Pretty handy if true, given TB was the biggest killer in the 1800s. My own family was severely afflicted, four close female relatives dying of the disease in the first half of the 1900s. They included my aunt and her baby daughter who were buried, through poverty, in the same casket, after having slept in the same bed.

Queen Elizabeth came first to Australia in 1954. Her gloved hand touched the mother of Kim Beazley before it was realised both Kim and his mother, Betty, had been brewing polio; Kim developed temporary paralysis. Human immunoglobulin containing antibodies to polio was sourced and apparently given to members of the royal household. Vaccination for polio only became available later that year – and the Queen soon had her children, including the then-Prince Charles, vaccinated– as an example to the realm.

Once more, we reach to prevention in its various forms, such as vaccination, testing and isolation. I am delighted that Australian research, with which I am involved, is using a new form of vaccine applied to the skin. It’s already in phase II human trials; a painless patch stimulates our immune system efficiently without the need of a cold chain or a needle. A true healing touch.

Before flights from China touch down, we must pay attention to the limited intelligence on cases and deaths shared by China. The new testing measures for travellers from China will still allow most people to travel. Chinese New Year arrives in a few weeks and will be marked by a mass migration both within and from China, with orders of magnitude more infections there than in Europe or the US.

China need not be offended by our stance as it imposes testing on incoming travellers, too. Our approach should slow the spread of a potential new variant, giving time to prepare: genome sequencing and determining the likely effectiveness of current therapies and vaccines. As the year of the Tiger draws to a close, the COVID problem can recede too, as we take effective public health measures.

Robert Booy is an honorary professor at the University of Sydney’s Institute of Infectious Diseases. He acknowledges advice on virology from Professor Gary Grohmann.

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