scorecardresearch
Follow Us:
Monday, January 18, 2021

Travel restrictions effective in countries with low number of COVID-19 cases: Lancet study

The study also suggests that travel restrictions may have been most effective during the early stages of the pandemic, and the measures are unlikely to be effective when the virus is already spreading rapidly within a country

By: PTI | New Delhi | December 8, 2020 1:20:40 pm
Researchers used detailed flight data to compare the number of expected COVID-19 cases arriving from international flights with the number of infections arising from transmission within individual countries. (AP Photo)

Travel restrictions are effective in countries with low numbers of COVID-19 cases, or that have strong travel links with nations experiencing high rates of the viral infection, according to a study published in The Lancet Public Health journal.

The study also suggests that travel restrictions may have been most effective during the early stages of the pandemic, and the measures are unlikely to be effective when the virus is already spreading rapidly within a country.

“We recognise that these measures carry a high economic and social cost, so it is important that governments use travel restrictions in a targeted way,” said Professor Mark Jit from the London School of Hygiene and Tropical Medicine, who led the study.

“Before introducing restrictions, they should take into account local infection figures, epidemic growth rates, and the volume of travellers arriving from countries heavily-affected by the virus,” Jit explained.

The researchers used detailed flight data to compare the number of expected COVID-19 cases arriving from international flights with the number of infections arising from transmission within individual countries.

They produced estimates of international travellers in May and September 2020 based on two scenarios.

One scenario used flight data for the same months in 2019, assuming no reduction in travel numbers, and the other scenario was based on the expected reduction in passenger numbers.

ALSO READ| Americans have begun planning post-vaccine travel; know the places they want to visit

Numbers of COVID-19 cases and infection rates were estimated using a mathematical model that adjusts recorded cases to take account of asymptomatic and unreported infections.

Results were determined based on how imported COVID-19 cases would affect local epidemic growth rates, using country-specific reproduction number, or R number, estimates.

Where imported cases accounted for more than 10 per cent of infections within individual countries, they were considered to have a major impact on growth of the epidemic, the study found.

The work estimated that when imported cases accounted for less than 10 per cent, their impact on the growth of the epidemic is usually small, while those below 1 per cent would have an almost undetectable effect on epidemic size.

The researchers noted that had there been no travel restrictions or reduction in travel volumes in May 2020, the imported COVID-19 cases would account for more than 10 per cent of infections in the majority of countries included in the analysis, the researchers said.

Imported cases would account for no more than 10 per cent of infections in 34 out of 136 countries, and less than 1 per cent in four, they said.

According to the estimates based on expected passenger numbers in May 2020, imported cases would have contributed to more than 10 per cent of total incidence in 74 countries, less than 10 per cent of total incidence in 62 countries, and to less than 1 per cent in eight countries.

However, by September 2020, had there been no travel restrictions or reduction in travel volumes, imported cases would account for more than 10 per cent of infections in only a small number of countries.

Imported cases account for less than 10 per cent of infections in 106 out of 162 countries, and less than 1 per cent in 21, the researchers said.

ALSO READ | Planning a trip in the future? Survey reveals top trends for 2021

According to the estimates based on expected passenger numbers in September 2020, travel restrictions would have contributed to more than 10 per cent of infections in only 37 countries, less than 10 per cent in 125 countries and less than 1 per cent in only 44 countries.

The findings indicate that international travel restrictions were most effective at limiting local transmission of the virus during earlier stages of the pandemic, said the researchers, adding this is because imported cases led to outbreaks in countries with very few or no existing cases.

For more lifestyle news, follow us: Twitter: lifestyle_ie | FacebookIE Lifestyle | Instagram: ie_lifestyle

📣 The Indian Express is now on Telegram. Click here to join our channel (@indianexpress) and stay updated with the latest headlines

For all the latest Lifestyle News, download Indian Express App.

Advertisement
Advertisement
Advertisement
Advertisement