Urgent need for more testing now

Photo: AZHAR MAHFOF/The Star

WE would like to bring readers’ attention to a recent report by a local news portal predicting that 10,000 active cases will occur by Nov 4. The number of active cases already passed 10,000 on Oct 28 (according to the Health Ministry’s Covid-19 portal). Our Covid-19 modelling group, which consists of several applied mathematicians, epidemiologists, public health specialists and a biostatistician, all from major public universities, predicted this earlier in the week.

We analyse a mathematical model of susceptible-infected-recovered-death (SIRD) type to calculate the active cases trajectory, which is predicted by the model till the end of this year; in comparison, we also plot the actual active cases in Malaysia. Overall, we can see that the SIRD model analysis agrees with the number of active cases and the model is able to mimic the trend of infection trajectories of our country’s Covid-19 scenarios. Based on the simulation of this model, we observed that the number of active Covid-19 cases in Malaysia would pass 10,000 cases as soon as Oct 27 or 28, as has happened.

Without proper suppression measures, once active cases achieve this five-digit level, the model predicted an exponential growth characteristic, and the figures will increase more rapidly. This trend is predicted to continue till next year, and this could very possibly overwhelm our healthcare infrastructure and medical resources.

Our observation is verified using a modelling approach that analyses nonlinear trends in the data, and the predicted trend has matched exactly the findings we obtained using the SIRD model. The number of active cases is expected to continue on an exponentially increasing trend under the existing control regime. What is more worrying, the predicted number of total deaths is following this trend also.

Our predictions and forecasts are based on existing data. Data may change in the days to come but the science behind these approaches is formulated to capture persistent trends in the data, and the persistent trend that we are seeing in our results is that the current control measures are not enough to tame the raging spread of infections. Based on the data, we can confidently say that up until Oct 1, Malaysia had everything mostly under control. But from then onwards the virus appears to have the upper hand.

Although our predictions are looking at the “worst case scenario”, we think it’s time to go full throttle with the intervention strategies. Movement control orders (MCO) in red zones must be adhered to more strictly, and quarantines and physical distancing must be taken more seriously because they are paramount if we are to break the chain of infections. We urgently need to reduce the strain on the nation’s medical resources.

We hope our predictions are able to highlight the importance of conducting more tests to detect community transmission and asymptomatic cases in Malaysia. If we increase testing capacity, then more possible cases will be picked up. While the number of cases is likely to increase due to more tests, new data from these tests will provide more information for Covid-19 modelling than what we have now. As a result, infectious disease modellers and epidemiologists would be able to predict more precisely the parameters for Covid-19 infectivity, for example, the reproduction number or R0 (pronounced R-naught, which is a measure of infectivity; an R0 of three, for example, means a person who has the disease will transmit it to an average of three other people, so the lower the R0, the better). The overall reproduction number for the whole country and the state-specific reproduction numbers will guide the control and prevention of Covid-19 not just for the whole country for but also for each state in Malaysia.

A similar strategy was employed by Singapore, which led to high numbers of daily Covid-19 cases initially but which eventually helped the country to curb the spread of infection effectively. This crucial information from community testing will help the Health Ministry to devise an early and effective contact tracing strategy because all newly identified active cases detected could be placed in a 14-day quarantine – a process epidemiologists call isolation – to contain the spread of this disease in the community further.

DR MOHD HAFIZ MOHD, ASSOC PROF DR NOOR ATINAH AHMAD, ASSOC PROF DR KAMARUL IMRAN MUSA & MOHAMMAD SUBHI JAMILUDDIN

Universiti Sains Malaysia