Covid-19: Travel Restrictions Are Largely Ineffective

Covid-19: Travel Restrictions are Largely Ineffective

It is perhaps a little unlikely that many subscribers will be attentive readers of the “Lancet”: the world’ leading medical journal.

Earlier in the month it published the results of research, based around the London School of Hygiene and Tropical Medicine, which shows that travel restrictions have only a very limited effect on the spread of disease.

The research is both welcome and highly relevant and interestingly was financed in part by the British government and the European Commission.

What might be of more interest could whether either party will take action based on the findings.

The methodology in summary:

✓ concentrated on two time periods, May and September

✓ used country data from the Open Sky Database notably avoiding the use of actual passenger numbers

✓ developed a Bayesian modelling framework to combine with Covid prevalence from source countries.

The study concluded that:

✓ in May imported cases were likely to have accounted for a high proportion of incidence in many countries where epidemics were close to the exponential tipping point

✓ in September the reverse was the case.

The project examined likely outcomes by country had there been no restrictions in place:

Further, based on their estimates of 2020 travel volumes in September imported cases represented:

✓ no more than 10% of incidence in 125 countries and

✓ less than 1% in 44 countries.

The findings do not suggest an end to international travel limitations. Rather they indicate that such measures need to be deployed selectively based upon incidence levels country by country and especially focusing on travellers from the most infected areas.

On the other hand in both New Zealand and China in September where incidence was very low, imported infections would heave posed a real threat.

Follow this link to the research summary:
https://www.thelancet.com/journals/lanpub/article/PIIS2468-2667(20)30263-2/fulltext

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