The risk of pre-symptomatic and asymptomatic transmission of SARS-CoV-2 infections
HKU SPH researchers recently published a paper on Clinical Infectious Diseases in cooperation with China CDC about the role of asymptomatic and pre-symptomatic transmission in spreading SARS-CoV-2 infections. By using the transmission event information collected via contact tracing from mainland China, this paper demonstrated temporal changes in the risk of transmission from index cases who had presented symptoms. It also compared the risk and severity of secondary infections by symptomatic status of the index. They found that around 38% of infections were attributable to exposure before index onset, while onward transmission after onset was less likely to occur and might be less severe from asymptomatic index cases.
Read more about this paper here: