The characteristics of COVID-19 transmission from case to high-risk contact, a statistical analysis from contact tracing data

EClinicalMedicine

Nichapat Sangkaew¹  Kristina Stosic²  Chayanon Phucharoen³ 

[1] COVID-19 Joint Force Operation Centre (Phuket Province), Phuket, Thailand;Corresponding author at: Faculty of Hospitality and Tourism, Prince of Songkla University (Phuket campus), Phuket, Thailand.;Faculty of Hospitality and Tourism, Prince of Songkla University (Phuket Campus), Phuket, Thailand;

关键词: COVID-19;    Household transmission;    Quarantine;    Probability of infection;   

DOI  :  

来源: DOAJ

【 摘 要 】

Background: As of 24th of August 2020, the number of global COVID-19 confirmed cases is nearly 24 million. In the same period, the number of recorded infections in Thailand has remained at approximately 3300. This paper explores the specifics of COVID-19 or SARS-CoV-2 transmissions in Phuket, Thailand's second most visited tourist destination Methods: High-risk contacts recorded by Phuket Provincial Public Health Office were analysed using the Probit model to investigate the risk factors for transmission from confirmed COVID-19 cases to their high-risk contacts. The analysis was further focused on the impact of quarantine measures in state provided facilities on contacts’ probability of infection. Findings: 15.6% of 1108 high-risk contacts were found to be infected, and they accounted for 80% of 214 confirmed cases in Phuket till 29th April 2020. Moreover, 10.68% of all high-risk contacts were confirmed to be infected before the quarantine, and 4.55% after the policy was enforced. In addition, a contact who lived within the same household with a confirmed case was 25% more exposed to infection when compared to a contact who did not share a household. Interpretation: Results confirmed that the quarantine policy, which mandated individual isolation in the state provided facilities for all high-risk contacts, diminished contact's chance of infection from the confirmed cases, especially in the epicenter districts. Our findings confirmed that sharing accommodation with an infected case, and exposure to a case with several documented secondary transmission, generally increased the SARS-CoV-2 infection probability. Finally, some confirmed cases do exhibit a higher risk of spreading SARS-CoV-2 to their contacts compared to a typical confirmed case. Further studies of high reproduction groups of infected patients are recommended. Funding: No funding was received for this research.

【 授权许可】

Unknown