Chinese researchers have found the virus behind COVID-19 seems to spread quicker and easier when economic activity is high.
The SARS-CoV-2 emerged in China's Hubei province late last year, and has killed more than 101,000 people - at least - since then.
Its early spread in January was aided by the 'Chinese Spring Festival Travel Rush', or 'Chunyun', which sees hundreds of millions of people head home to mark the Chinese New Year.
"The virus quickly spread from Wuhan to other parts of China," a new study published online by Chinese scientists reads.
According to official statistics, just over 80,000 Chinese on the mainland ended up infected. Despite its Communist background, China has wider inequality than most Western nations, giving researchers a chance to see how the highly infectious virus might spread in areas of differing wealth.
The new research found 53.9 percent of confirmed infections happened in cities in the top 20 percent of GDP, while only 3.3 percent happened in cities in the bottom 20 percent - the researchers said there was a "very significant positive correlation" between infection rates and economic activity, measured by GDP.
"In areas with high economic development level, the epidemic risk is high, and the more active and strict epidemic prevention measures should be taken," the researchers said, suggesting lockdowns might need to last longer in richer areas than poor.
"Generally speaking, areas with high economic development have relatively higher flow of people and logistics, which also is a way of transmission for viruses. Therefore, during the epidemic period, we should minimise the flow, reduce the aggregation and prevent the virus from spreading among people...
"In developing areas, the risk of epidemic is lower than that of high economic development areas, but low risk is not without risk."
Many countries have implemented lockdowns to stop the spread of COVID-19, which appear to be working - but at the cost of economic activity.