Second-wave warning:
Veteran computer scientist Yuen Poovarawan yesterday warned that while the country has managed to curb the domestic spread of coronavirus, the risk of a second wave remains.
Assoc Prof Yuen, a senior member of Kasetsart University’s Department of Computer Engineering, said that the ability of the disease to spread can be described as the reproduction number, or the R-value.
“One infected person can spread the disease to two people, who then spread it to four others, who continue to spread it to eight others, and so on. The rate can vary because some of them can be superspreaders, but the point is that our intervention can reduce the R-value.
“The World Health Organization estimates that the reproduction number of Covid-19 stands at 1.4-2.5. However, social distancing and public health measures can diminish the number,” he told a webinar organised by the foreign pharmaceutical company Abbott yesterday.
The virtual forum was organised on the theme of “Covid-19 and Computing Science: A Passion of Learning with Imagination”.
“Scientists calculate the reproduction number backwards by using data of people dying, being hospitalised, or testing positive for the coronavirus. If the R-value is lower than one, the disease will soon peter out,” explained Assoc Prof Yuen.
He said the country intervened to curtail the outbreak two months ago rather than let nature take its course, illustrating the flattened red curve [the infected population] on the chart.
“On March 16, the government issued six measures to reduce the soaring R-value. Then it invoked the emergency decree on March 26 and imposed a night curfew on April 3. All of these have been done to flatten the curve, but if we let our guard down, there will be a second, third and fourth wave,” he said.
In the uncontrolled model, the red curve will rise exponentially, then flatten over time once the majority of the population have been infected and developed immunity naturally. However, Assoc Prof Yeun said it takes longer than two or three months to reach the peak of an outbreak.
“In Thailand, we saw a surge of coronavirus cases from the boxing stadium and night entertainment venues, but we imposed lockdown and social distancing measures to mitigate the spread of the disease,” he said.