A study by a group of researchers at Harvard University has suggested that Indonesia should have confirmed cases of the novel coronavirus already, considering the high air travel volume from Wuhan, the epicenter of the outbreak in China, to the country.
The study, carried out by researchers at the Harvard T.H. Chan School of Public Health, revealed that Indonesia’s zero confirmed cases “may suggest the potential for undetected cases in these locations given the expected connection before travel control measures were implemented”.
However, the study has not been peer-reviewed. It was published on pre-print server medRxiv on Wednesday.
The finding was based on estimates of air travel volume from Wuhan to international destinations and a generalized linear regression model to the predict imports of novel coronavirus cases across 26 locations.
With an average daily number of passengers of about 100 people, the model showed that Indonesia should have confirmed one to 10 cases of the novel coronavirus infection.
Apart from Indonesia, researchers also found that Cambodia and Thailand had confirmed cases lower than the model predicted. As of Saturday, Thailand has confirmed 25 cases of infection, while Cambodia had reported one case.
Meanwhile, Vietnam has reported the same number of cases as the study expected. Singapore had also followed suit as the number of confirmed cases in the country was the same as the study’s 95 percent upper-bound interval at the time it was conducted.
“We recommend that outbreak surveillance and control capacity should be rapidly strengthened in those locations lying below the 95 percent [prediction interval] lower bound to ensure cases are detected if occurring and avoid the emergence of self-sustained transmission,” researchers said in the study.
Another study conducted by researchers at United States-based non-profit research institute RTI International in collaboration with researchers from Harvard University, the University of Oxford and the University of Toronto, also showed that Indonesia should be on alert and expect new cases.
The study, published on RTI’s website, was carried out by regarding Twitter activity as a proxy for human mobility to predict the spatio-temporal spread of the 2019 novel coronavirus at a global level.
Researchers collected tweets produced during the time period when exposure to the coronavirus first occurred up until travel into and out of Wuhan was restricted.
They further filtered the database to include users posting at least two tweets on two days consecutively within the area of Wuhan to make sure that the user was physically in the city. The selected users were then reviewed to determine whether they had traveled outside of Wuhan based on the geolocation data of each tweet.
“Our main message to health officials is […] to draw up plans to sensitize the population and health providers to the possible emergence of 2019 novel coronavirus, particularly in patients with a history of travel to Wuhan,” said Richard Reithinger, the global health vice president of RTI, as quoted on RTI’s website.
Indonesia has suspended flights to and from Wuhan following the city’s lockdown since Jan. 24. The government also imposed a travel ban to and from mainland China on Wednesday in response to the outbreak.
Authorities have also enforced health screenings at hundreds of entry points across the archipelago.