Covid-19 is a return to the days of smallpox and typhus – Professor Hugh Pennington

Scientists moved quickly to identify this new strain of coronavirus, which has some similarities with ‘19th-century diseases’ that were feared until modern medicine intervened, writes Professor Hugh Pennington.

The USNS Comfort hospital ship in New York is a throwback to the 1860s when two British warships were used as hospital ships in Lndon during a smallpox outbreak (Picture: Kena Betancur/Getty Images)

Was it possible to predict the current pandemic? No. The new virus, officially called Sars-CoV-2, causing the disease called Covid-19, emerged without doubt by chance when a bat coronavirus got into another animal (probably a pangolin) and then became able to infect humans. Virus mutations and gene swapping almost certainly played important parts in its evolution.

Such events are unpredictable by their very nature. And even when we prepare for possible pandemics caused by microbes with which we are familiar they often spring surprises. Much of our response to Covid-19 builds on pre-existing plans to combat influenza.

The UK Pandemic Plan in the early 2000s assumed that the next pandemic would be caused by a bird virus, that it would originate in China, that it would build momentum there before arriving here, that it would spread throughout the UK within one to two weeks, and that it would cause between 55,000 and 750,000 deaths.

But, when it came in 2009, the virus had not read the plan. It came from pigs. It originated in Mexico. Only four days elapsed between its identification there and its arrival in the UK, it did not spread rapidly to all population centres but affected the West Midlands of England and the Clyde Valley earlier than other areas, and not more than 460 suffered a fatal infection.

Coronaviruses infect many warm-blooded animals, including humans, pigs, dogs, cats, rabbits, mice, rats, cows, turkeys and chickens, as well as bats, but they usually stick to only one species. The most frequent infection caused by human coronaviruses is the common cold. They cause about 20 per cent of them.

How coronavirus got its name

We know very little about them from the medical point of view because the illnesses they cause are so trivial that studying them and testing for them has been deemed to be a waste of time. They were discovered in 1966 at St Thomas’ Hospital in London by the brilliant electron microscopist, June Almeida.

Born in Glasgow, she had built her career in Canada. She had a hand in naming them “coronaviruses”; the knobs on the ends on the spikes jutting out of the virus particle surface gave them a crown-like appearance.

Until Sars (severe acute respiratory syndrome) appeared in 2002, human coronaviruses were curiosities only of interest to academic molecular virologists studying their unusual RNA genomes. It was just as well that they had built up this knowledge; it came in very handy when the Sars virus was grown in March 2003 from patients in Hong Kong, New York, and Vietnam.

The first cases of Sars had almost certainly occurred in Guangdong Province in China in November 2002, and the Chinese authorities had kept quiet about them. The World Health Organisation was not alerted until February 2003. Once the new viruses had been isolated in March, it set up an unprecedented collaboration between scientists around the world and on 16 April the Sars virus was conclusively identified as a new coronavirus. But by then the virus had spread world-wide. The epidemic lasted until July 2003. It infected 8,096 people in 29 countries, and had a fatality rate of 9.6 per cent, a good deal higher than Covid-19.

Speedy response in China this time

Sars taught a bitter lesson to the Chinese authorities. It was obvious that secrecy about an epidemic and denials of its existence are policies doomed to fail. Eventually the virus will win.

On 26 December 2019, four unusual cases of pneumonia were noticed at a hospital in Wuhan. Three more were found in the same hospital the next day. A patient with the same kind of pneumonia had samples taken from deep in the lungs. A virus from them was grown in tissue cells in the laboratory. Under the electron microscope, it had knobs on the ends of its surface spikes, just like the viruses seen by June Almeida.

An assay looking for the RNA of coronaviruses related to Sars was positive. It was sequenced using state-of-the-art US and British sequencing machines. It was a new coronavirus – the one that causes Covid-19. The sequence information was published globally on 12 January, and test kits using this information had been developed within 24 hours.

The speed of response of the Chinese doctors and scientists was remarkable, even if it was likely that Sars was very high on the list of causes of the severe clusters of pneumonia. It is probable that if a new coronavirus had emerged in the UK we would have been extremely lucky to identify it with such speed. To be fair, we don’t have the same bats as in China and our butchers don’t sell pangolins. But coronaviruses in various species are not rare here.

Hospital ships are not a new idea

Covid-19 evolved in the 21st century but in many ways is a 19th-century disease in terms of our ability to cope with it. Despite typhus being a bacterial disease transmitted by lice, the similarities are striking. The brand new Louisa Jordan hospital under construction in Glasgow commemorates the Scottish nurse who was one of many healthcare workers who died of it during the Serbian epidemic in 1915, in which more than 150,000 perished.

Just as with Covid-19 today, at that time there were no specific treatments and no vaccine. And another similarity is the marked effect of age on the outcome of infection. Most children recover from typhus, whereas in the over 60s about 60 per cent die.

Another virus illness that shares similarity with Covid-19 is smallpox. I declare an interest as one of the select band of virologists who have handled the virus in the laboratory.

Like Covid-19 (and Sars before), it specialised in infecting hospital health care workers; 19 per cent of cases in the 45 outbreaks in Europe between 1950-1971 were in hospital staff, many of them fatal.

And in the big outbreak in 1881, London didn’t build a Nightingale Hospital but rented two wooden warships built in the 1860s – the 91-gun Atlas and the 50-gun Endymion – from the Admiralty and converted them into hospital ships moored in the Thames. A particular problem was trying to stop delirious patients jumping overboard. Whether this will be a problem with the 1,000-bed hospital ship USNS Comfort moored off New York today, only time will tell.

Hugh Pennington is emeritus professor of bacteriology at the University of Aberdeen

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