Should Australia reopen international borders?

With the beginning of the COVID-19 pandemic, most countries closed their borders to international travelers earlier this year to prevent infected people from entering and spreading the community. Many international borders remain closed or severely restricted due to quarantine measures in order to interrupt the transmission chain of coronavirus 2 (SARS-CoV-2) with severe acute respiratory syndrome. The virus has infected nearly 39 million people in almost every country in the world.

Australian scientist Jessica Liebig of the Commonwealth Scientific and Industrial Research Organization (CSIRO), along with colleagues from the Queensland University of Technology and the University of New South Wales, examined the risks associated with reopening international borders for travelers to Australia. Your study with the title: “Should the international borders open again? The effects of travel restrictions on the COVID-19 import risk ”will be published on the preprint server medRxiv *.

background

In less than three months, the SARS CoV-2 spread to over 100 countries via international travel. A pandemic was declared by the World Health Organization (WHO) on March 11, 2020. The authors write that this led many nations to refuse entry to international travelers.

The researchers added that this ban and restriction on international travel have serious economic consequences. This economic loss can be quantified, but other parameters such as unemployment and social impact have not been examined. They stated that two factors determine the expected number of COVID-19 imports into a country. These are:

• Incoming travel volume
• Incidence rates of the disease in the countries of origin

Estimated Daily COVID-19 Imports. The model estimates that between January 1 and May 30, 2020, taking into account the current travel restrictions (solid line), a total of 6,003 COVID-19 cases were imported into Australia. Without travel restrictions, a total of 48,715 cases would have been imported in the same period (dashed line). The shaded values ​​indicate the 95% confidence interval of our estimates, which was obtained by averaging over 100 model runs.

Scenario in Australia

Australia is an island country and most of the incoming international travel is by air. The researchers wrote that the first case was discovered on the 25th^th In January 2020 and a week after that, some border closings came into force. Soon the number of cases increased until stricter restrictions on international travel were put in place.

Travel restrictions from Iran, South Korea and Italy were introduced on Jan.^st, 5^th, and 11^th from March 2020. All foreign travelers have been banned from entering Australia for 20 years^th March 2020.

In Australia, the researchers wrote, “border control” gathers all information about people entering the nation and this is published in an anonymous database. For this study, the team collected the number of passengers who would have come to the nation had it not been for travel bans. They used a mathematical model called “SARIMA models (Seasonal Auto-Regressive Integrated Moving Average)”. They also gathered the incidence of COVID-19 cases using the information on the European Center for Disease Prevention and Control (ECDC) website.

Study design

The team developed a comprehensive framework for modeling daily COVID-19 imports, taking into account various international travel restrictions. Each of these levels corresponded to the import of cases and the incidence of new cases. Finally, they calculated and assessed the effectiveness of the travel bans introduced by the Australian government.

When estimating the travel volume, it was initially assumed that there were no travel restrictions. This was based on incoming travel data based on the five year history from January 2015 to December 2019. Then speculation began based on the travel restrictions the Australian government had put in place in the COVID-19 situation. They examined the impact of travel restrictions (or none) between January 1 and June 30, 2020.

Results

The results showed that international travel bans in Australia reduced imports of COVID-19 cases into the country by 87.68 percent (between 83.39 and 91.35 percent) between January and June 2020. The overall results of the study were:

• The travel restrictions allow Australia to cut COVID-19 imports from China by 94.45 percent (between 91.77 and 96.32 percent) during the study period
• 1,938 fewer cases were imported from China
• In February, 19.57 percent of the expected number of Australian citizens / residents returned from China
• COVID-19 imports from Iran have declined 32.81 percent (14 new cases have been imported) since restrictions were imposed from that country on March 1
• COVID-19 imports from South Korea have declined 94.41 percent since restrictions were imposed from that country on March 5. A total of 433 fewer cases were imported from South Korea.
• 5.49 percent of Australian citizens or residents returned to Australia in March.
• COVID-19 imports from Italy have declined 77.9 percent since restrictions were imposed from that country on March 5. A total of 994 fewer cases were imported from Italy.
• Between 21^st March and April 30, between 15 and 22 cases per day were imported.
• Between May and June, the average decrease was three cases per day.
• The largest proportion of imported COVID-19 cases were from the United Kingdom (1,579 cases average).
• The second largest source was the United States of America with an average of 957 cases.

Conclusions and implications

This study showed that case import rates were due to overseas travel to Australia and what it would be like if there were no travel restrictions. The researchers concluded: “The authorities can take the information provided into account when planning a gradual reopening of international borders.”