A data driven change-point epidemic model for assessing the impact of large gathering and subsequent movement control order on COVID-19 spread in Malaysia

Abstract

The second wave of COVID-19 in Malaysia is largely attributed to a four-day mass gathering held in Sri Petaling from February 27, 2020, which contributed to an exponential rise of COVID-19 cases in the country. Starting from March 18, 2020, the Malaysian government introduced four consecutive phases of a Movement Control Order (MCO) to stem the spread of COVID-19. The MCO was implemented through various non-pharmaceutical interventions (NPIs). The reported number of cases reached its peak by the first week of April and then started to reduce, hence proving the effectiveness of the MCO. To gain a quantitative understanding of the effect of MCO on the dynamics of COVID-19, this paper develops a class of mathematical models to capture the disease spread before and after MCO implementation in Malaysia. A heterogeneous variant of the Susceptible-Exposed-Infected-Recovered (SEIR) model is developed with additional compartments for asymptomatic transmission. Further, a change-point is incorporated to model disease dynamics before and after intervention which is inferred based on data. Related statistical analyses for inference are developed in a Bayesian framework and are able to provide quantitative assessments of (1) the impact of the Sri Petaling gathering, and (2) the extent of decreasing transmission during the MCO period. The analysis here also quantitatively demonstrates how quickly transmission rates fall under effective NPI implementation within a short time period. The models and methodology used provided important insights into the nature of local transmissions to decision makers in the Ministry of Health, Malaysia.

COVID-19 in Malaysia: Descriptive Epidemiologic Characteristics of the First Wave

“…Similarly, the first wave lasted for a shorter duration compared to the second ( n = 206 days) and third ( n = 468 days) [ 37 ]. The first wave occurred as a result of imported cases entering Malaysia from China and Singapore, while subsequent waves occurred as a result of mass gathering events and introduction of new variants of concern [ 7 , 38 ]. With regard to disease transmissibility, the first wave reported much lower disease transmissibility (R 0 = 0.9) compared to the second (highest R t = 3.4) and third (highest R t = 1.72) [ 7 ].…”

“…With regard to disease transmissibility, the first wave reported much lower disease transmissibility (R 0 = 0.9) compared to the second (highest R t = 3.4) and third (highest R t = 1.72) [ 7 ]. In addition, the outbreak control measures transitioned from containment (first wave) to mitigation strategies during subsequent COVID-19 waves in Malaysia [ 38 ]. Containment measures such as early detection, isolation/quarantine and extensive contact tracing were effective in controlling the outbreak during the first wave as there were low case numbers, the majority of which were imported cases that were identified, tested, and isolated early.…”

“…In addition, the extensive contact tracing performed enabled the quarantine of close contacts and detection of additional cases, which subsequently prevented local transmissions. During subsequent waves of COVID-19, mitigation strategies were instituted, as there were more cases with higher disease transmissibility that were attributed to mass gathering events [ 7 , 38 ] and the introduction of new variants of concern.…”

Modified susceptible–exposed–infectious–recovered model for assessing the effectiveness of non-pharmaceutical interventions during the COVID-19 pandemic in Seoul

“…Nonlinearity is related to the heterogeneous disease characteristics of the population, which are characterized by probability distributions for susceptibility and infectivity. Dass et al (2021) explained how the resulting epidemic model that includes heterogeneity leads to the power transmission dynamics. Novozhilov (2012) also showed that the power-law function can be inferred from heterogeneous susceptible, infectious, and recovered models.…”

Sarawak Covid-19: Effects of Pre-Festival Mobility and Festival Gatherings

“…For instance, in Malaysia, there are two significant mass gathering events which have led to the second and third waves of the outbreak in the nation. The first was the Tabligh gathering event (Che Mat et al, 2020;Dass et al, 2021) and the other was the Sabah election (Lim et al, 2021), which was held on the 26 September 2020. Unlike Peninsular Malaysia and Sabah, the region of Sarawak was spared from the third wave of the outbreak.…”