A group of British researchers have generated a predictive global risk map for the like spread of Covid-19 over the next three months based on data from 60,000 of the estimated 5 million Wuhan residents who had left the city where the virus emerged before the critical lockdown was imposed.
Data published by Southampton University’s World Pop Project research group used map location data from Chinese tech giant Baidu in combination with international flight itineraries to make the map.
Our updated analyses on @MedArXiv : 'Assessing spread risk of Wuhan novel coronavirus within and beyond China, January-April 2020: a travel network-based modelling study' with Chinese CDC and Bluedot: https://t.co/r0iihEhdnu pic.twitter.com/7krJQq1KxX
— WorldPopProject (@WorldPopProject) February 6, 2020
The paper, published on medRxiv, estimates that a total over 59,912 air passengers left Wuhan to 382 cities outside of mainland China in the days leading up to when the city was quarantines on 23 January. This includes 834 infected individuals.
The website, medRxiv included a note to say that the paper is a pre-print and has yet to be peer-reviewed, adding that given that it includes new medical research that has yet to be evaluated, it should not be used to guide clinal practice.
“Where these travellers went and how high the risk of further spread of the virus within and beyond China remains an open question,” they wrote.
The researchers noted that a majority of the cities that people from Wuhan travelled to were mostly in Asia, though other destinations like the United States and Australia were prominent.
The authors wrote, “The majority of these cities were in Asia, but major hubs in Europe, the US and Australia were also prominent, with strong correlation seen between predicted importation risks and reported cases seen,” wrote the authors.
“Because significant spread has already occurred, a large number of airline travellers (3.3 million under the scenario of 75 per cent travel reduction from normal volumes) may be required to be screened at origin high-risk cities in China and destinations across the globe for the following three months of February to April 2020 to effectively limit spread beyond its current extent,” they explained.
According to the study, the top 10 destinations for traveller from Wuhan include Thailand, Japan, Hong Kong, Taiwan, South Korean, the United States, Malaysia, Singapore Vietnam and Australia.
And in Africa specifically, the countries that topped the list include Egypt, South Africa, Ethiopia, Mauritius, Morocco, Nigeria and Kenya.
The authors concluded that further spread of Covid-19 within China and international exportation is likely to occur.
“All countries, especially vulnerable regions, should be prepared for efforts to contain the 2019-nCoV infection,” they advised.
Alarmingly, molecular virologist Jin Dong-Yan at Hong Kong University’s School of Biomedical Sciences said to AFP that “it is definitely too late”.
“Five million out. That’s a big challenge. Many of them may not come back to Wuhan but hang around somewhere else.
“To control this outbreak, we have to deal with this. On the one hand, we need to identify them. On the other hand, we need to address the issue of stigma and discrimination.”
Quarantines around the world
In efforts to curb further spread of the virus, several countries including the US and Australia have banned travellers from China from entering and warned their own citizens from travelling there.
On 2 February, Singapore imposed a ban on all travellers arriving from mainland China and those who have a China passport. They will also be barred from transiting in Singapore.
However, the restriction does not apply to Singaporeans, Permanent Residents and Long Term Pass holders who have been to China or using a China passport. They will instead be subjected to a leave of absence of 14 days, which health experts think is the incubation period for the virus.
The World Health Organisation’s (WHO) latest situation report on 12 February reported 2,068 new cases around the world in the past day, bring the total number of cases up to 45,171. Most of the confirmed cases—44,730—are in China which has also reported 1114 deaths so far. Another 8,204 cases in China remain in severe condition.
The largest cluster of infection outside of China is the cruise ship Diamond Princess is quarantined just off the coast of Japan in the Yokohama port since. So far, 218 passengers and crew out of the 3,700 onboard have tested positive for Covid-19, including 6 Singaporeans, with 44 cases being confirmed just this morning (13 February).
“Our guests and crew on board Diamond Princess are the focus of our entire global organisation right now and all of our hearts are with each of them,” Princess Cruises president Jan Swartz said in a statement.
“In this unprecedented situation, the Japanese Ministry of Health authorities are working with us collaboratively on additional enhancements, approving new procedures as we adapt our process to the unique challenges of this situation.”