By Tamura Kenji, senior staff writer
The government’s Go To Travel campaign was likely a major factor behind the surge in COVID-19 cases in Hokkaido last autumn, according to an analysis of the genome sequences of the novel coronavirus.
That comes as the central government is considering reviving the tourism promotion campaign as early as January.
It will likely become necessary for the government to assess past outbreaks and then draw up stronger anti-virus measures before resuming the program.
A team of researchers from Keio University, Hokkaido University and the Japan Anti-Tuberculosis Association’s Research Institute of Tuberculosis analyzed the genome sequences of the virus.
The information was obtained from samples taken in and outside Hokkaido between June and December 2020. The team also used an international database to make detailed comparisons.
The researchers studied subtle differences in the genome sequences to project how the virus likely spread in the northernmost main island.
The results show that different types of the virus from what was then dominant in Hokkaido came into the island at least eight times between July and November last year and then spread there by replacing existing strains.
The strain of the virus responsible for the bulk of the surge in infections in Hokkaido in autumn 2020 apparently came from the Kinki region at the end of September that year, according to the researchers.
They also found that many strains of the virus had been brought into Hokkaido from Tokyo and other parts of the greater Tokyo metropolitan area since October last year, likely accounting for five of the eight instances.
The Go To Travel campaign started on July 22, 2020. Trips to and from Tokyo were added to the program in October that year.
Data from the Japan Tourism Agency shows the number of travelers staying overnight in Hokkaido plunged in spring last year due to a COVID-19 state of emergency.
But the number of overnight visitors from the Kinki region in September that year rebounded to about 60 percent of that from a year earlier. The figure for October 2020 was roughly 80 percent of what it was a year ago.
The data also shows the number of overnight visitors from the Tokyo metropolitan area in October last year returned to about 80 percent of the level seen a year earlier.
In Hokkaido, new COVID-19 cases began rising around the latter half of October 2020 with many reports of cluster infections at hospitals and facilities for elderly people.
“More people started coming to Hokkaido after Tokyo was added to the travel program,” said a member of the research team. “That apparently helped spread the virus further.”
Sapporo, which is the capital of Hokkaido, and Osaka were removed from the campaign in late November 2020 following a spike in new infections. The central government had halted the program nationwide by the end of December.
When it resumes the campaign, the government plans to ask users to show proof of vaccinations or negative COVID-19 test results.
But no scientific studies have been conducted to assess the effectiveness of such measures in preventing the spread of the virus.
“We’ve seen many cases where infections spread after more people started traveling from virus hotspots to regional areas,” said Koji Wada, a professor of public health at the International University of Health and Welfare. “If the government wants to resume the travel program, it should require users to travel only with their family members and avoid travel on weekends and consecutive holidays to prevent the spread of the virus.”
The study was published in the journal Travel Medicine and Infectious Disease: (https://www.sciencedirect.com/science/article/pii/S1477893921002519?via%3Dihub).