Hong Kong researchers conducted a new study and found that lockdowns may not end until we have a COVID-19 vaccine.

According to the study, which is based on the Chinese experience, nations eagerly waiting to end the lockdown will have to be extremely cautious, monitor new cases and adjust the controls until there is a vaccine available to prevent COVID-19, the disease caused by the new coronavirus.

In China, officials implemented aggressive controls over daily life throughout the lockdown, ending the first wave of COVID-19; however, there is still a danger of a second wave, the researchers noted.

Lead researcher Prof. Joseph T Wu of the University of Hong Kong said, “While these control measures appear to have reduced the number of infections to very low levels, without herd immunity against COVID-19, cases could easily resurge as businesses, factory operations, and schools gradually resume and increase social mixing, particularly given the increasing risk of imported cases from overseas as COVID-19 continues to spread globally.”

Chinese authorities have pushed the reproductive number from two or three to below one, which is effectively shrinking the epidemic.

The reproductive number is the number of people on average that one person with COVID-19 will infect.

However, the researchers cautioned that the reproductive number is likely to increase again if lockdown is ended too quickly and the lifting of controls is extensive. They say countries should keep a close watch on what is happening.

Wu explained, “Although control policies such as physical distancing and behavioral change are likely to be maintained for some time, proactively striking a balance between resuming economic activities and keeping the reproductive number below one is likely to be the best strategy until effective vaccines become widely available.”

The study, published in the medical journal Lancet, found that the death rate in China is now much lower than before. For instance, in Hubei province, where the outbreak began, the death rate is 1 percent, which previously had a death of 6 percent.

Senior study author Prof. Gabriel Leung of the University of Hong Kong said, “Even in the most prosperous and well-resourced megacities like Beijing and Shanghai, healthcare resources are finite, and services will struggle with a sudden increase in demand.”

“Our findings highlight the importance of ensuring that local healthcare systems have adequate staffing and resources to minimize COVID-related deaths,” he added.

The researchers analyzed the local Health Commission data of confirmed coronavirus cases from mid-January to February 29 in Beijing, Shanghai, Shenzhen, Wenzhou and the 10 provinces outside Hubei.

Ending the lockdown too quickly would allow the rate of infections to rise again, which could incur both health and economic loss.

The researchers explained, “Striking a balance between allowing economic activities and keeping controls tight enough to prevent a rise in infections is likely to be the optimal strategy until effective vaccines become widely available, despite the fact that control policies, including social distancing, behavioral change, and public awareness will probably be maintained for some time.”

Globally, the coronavirus has affected more than 1,518,700 and killed over 88,500 so far. The United States health officials have reported 435,128 confirmed cases and 14,795 deaths so far.