The National:

AT the start of current pandemic, the World Health Organisation and others advised that restricting international travel was not an effective way to stop the spread of SARS-CoV-2, the virus that causes Covid-19. We now know that they were wrong.

The deadliest infectious disease event of the last century, the 1918-19 Spanish Influenza pandemic, was propagated by the main form of mass transportation at the time: sea travel during the closing stages of World War I.

This century’s biggest pandemic (so far) has in turn been spread by international air travel. Numerous research studies in the countries hardest hit by Covid-19 (for example the United Kingdom, United States, and Brazil) have arrived at the same findings regarding importation. The virus arrives in hundreds or thousands of separate events, and from these is seeded to spread throughout the entire population.

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At the start of this pandemic, I was involved in research looking at the arrival of SARS-CoV-2 in Scotland. Researchers from the University of Edinburgh and Glasgow, alongside NHS colleagues, examined epidemiologic and viral genomic data to understand how Covid-19 arrived here. Sequencing of the coronavirus allows us to classify it within lineages (subgroups of the virus) and identify where it arrived from, and work out how it spreads in time and space. We found that the virus had been introduced at least 283 separate times, mainly from continental Europe, and most commonly from Italy.

I believe that we could have avoided this first wave in Scotland. The novel coronavirus was first reported to the WHO on January 3, 2020. By the January 14 we knew that there was human to human transmission, and by the February 9 there were reports of it being spread by attendees at international conferences, in this case a business meeting in Singapore.

Despite this large conferences were still being held in Scotland at the end of February. By February 21 we knew that SARS-CoV-2 was spreading within Italy. But in Scotland we were too slow to act: advice was issued to self-isolate after returning from travel to selected parts of Northern Italy only, and not from Italy as a whole, four days later. Only on March 10 did the Scottish Government advise all international travellers to self-isolate on return from travel abroad. And only in early June did the UK Government start to enforce these quarantine rules.

The findings from our research were presented by the Scottish chief medical officer on June 9 and also made publicly available at this point. The first lockdown, although painful in a number of ways, and extended for longer in Scotland than in England, was highly effective.

By some days in July we were down to just two confirmed Covid-19 cases in the entire country. Further research, conducted by my academic and NHS colleagues, suggests that there were only a handful of viral lineages left at this point in Scotland, each causing a small number of cases. But by September we were back to rising case counts. The source of these new cases? Travel again, this time from England and continental Europe.

Screening travellers is not enough. We know that airport screening is resource intensive, and often ineffective due to the incubation time of the virus. The countries that have handled this pandemic best are those that have been able to secure and control the passage of people across their borders. Taiwan, Australia and New Zealand, to pick from the small number of countries that have managed to keep case counts relatively low, introduced stringent travel restrictions from the start of the pandemic.

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Most importantly, they adopted measures to ensure that new arrivals complied with quarantine regulations. Their low case rates and tight handle on cases allows them to act quickly and decisively to investigate and contain outbreaks. In August, when a cluster of four cases was detected in Auckland, New Zealand, this city of 1.6 million people went into lockdown for 19 days. This strategy has proven highly successful: The last case of community transmission in New Zealand was on the November 18; all cases since then have been imported by travellers returning from abroad, and contained on arrival.

In contrast in a Scotland with (at last count) 2529 cases a day, this degree of disease surveillance and control remains a distant dream. More vaccines will be arriving soon, but so far only around 100,000 adults in Scotland have been vaccinated, leaving 4.3m unprotected.

By May we may well have vaccinated those over 50 and the most vulnerable but we are unlikely to have full (adult) population coverage until late summer or the autumn. Even these optimistic schedules are contingent on vaccine availability: manufacturers are already struggling to keep up with demand. In addition, as yet we have no clinical trials to guide vaccinating the 1m children and young people in Scotland.

READ MORE: Calls to close borders as UK Covid cases hit new record high

Given that we can’t rely on vaccines to get us out of our current dire situation, let’s learn from our previous mistakes, and take lessons from those who have handled the pandemic best.

Let’s continue to restrict travel, including from England, unless it is absolutely essential, as outlined by the First Minister yesterday. Let’s strictly enforce breaches of travel quarantine. Let’s think hard about continuing these travel restrictions beyond lockdown, until national case numbers are so low that we can effectively investigate and contain local outbreaks. Let’s aim to seamlessly transition from a Scotland with very low case numbers, to one where everyone is vaccinated. Let’s minimise unnecessary death and disruption to healthcare and education, and make sure that this lockdown is the last one we have to endure.