Henry Surendra, Eijkman-Oxford Clinical Research Unit (EOCRU)

International and local media organisations have reported that Indonesia holds one of the highest COVID-19 death rates in the world.

Indonesia’s reported death rate is below Italy’s (10% of confirmed cases), which has recorded the highest number of deaths in the world. But, Indonesia leads among countries in Southeast Asia and its death rate is almost double the global mortality rate of 4.8% based on data from Johns Hopkins University.

As of the end of March, the Indonesian government reported 136 deaths (around 8.9%) out of a total of 1,528 confirmed cases. That means around nine out of 100 people who have contracted COVID-19 have died in Indonesia.

However, the current calculation of the death rate in Indonesia does not reflect the reality on the ground because the number of actual cases in the community is estimated to be higher than the number of confirmed cases.

The percentage of deaths due to COVID-19 in Indonesia should be lower because the country has yet to detect the majority of people (cases) infected with COVID-19.

There are at least three facts that influence the calculation of the percentage of COVID-19 deaths in Indonesia.

1. Very few people have been tested

Indonesia has a population of more than a quarter of a billion. More than eight million people live in its capital Jakarta – the epicentre of the country’s outbreak. But the country has only tested 6,663 people for COVID-19 as of April 1.

So far, the government has only focused on examining people who had been in contact with confirmed patients or who had been travelling to infected areas in the last 14 days and show symptoms such as fever (more than 38℃), cough, sore throat and shortness of breath.

Mathematical modelling by Timothy W Russell and the research team from the London School of Hygiene and Tropical Medicine in the UK estimates Indonesia only detects around 4.5% of the total symptomatic cases in the community.

In other words, there were possibly around 35,000 undetected symptomatic cases in Indonesia by the end of March – assuming the number of cases in Indonesia is doubling every six days as reported Max Roser and team from Oxford University.

The percentage of case findings in Indonesia is meagre when compared to South Korea, which has been able to detect 78% of symptomatic cases by carrying out mass testing.

Russell’s study also reported a low percentage of symptomatic case findings in countries with a high number of deaths, such as Italy, Spain and Iran.

This likely reflects the trend of slow case finding in countries with a high number of deaths, including Indonesia.

Almost three weeks after the first case was announced, the government started mass and rapid testing in Jakarta, West Java and Banten. We may see results form this test drive in the next few weeks.

2. The majority of infections are mild or without symptoms

The World Health Organisation (WHO) reports 80% of people with COVID-19 have mild symptoms (similar to normal flu symptoms) or don’t show symptoms at all. WHO also reports around 15% of cases show severe symptoms, and 5% are critical. Imagine a pyramid where the most critical cases are at the top.

Under Indonesia’s testing protocols, infected people with mild or no symptoms will likely go undetected.

Research done by the Imperial College London also reported the majority of people infected with COVID-19 go undetected because they only experience mild symptoms, unspecific symptoms or don’t experience symptoms at all.

These findings indicate the number of COVID-19 cases reported to date is still very far from the actual number of cases in the community, including in Indonesia.

3. Deaths of patients with underlying chronic illness

The presence of underlying conditions in COVID-19 patients makes it difficult to conclude the cause of death.

It could be that a confirmed COVID-19 patient died from a chronic illness. In general (not during the COVID-19 pandemic), WHO reports six out of ten deaths in the world are due to chronic illness.

To date, there have been no studies that specifically measured mortality rates that were purely caused by COVID-19 in the world.

The majority of deaths in COVID-19 patients occur in patients with underlying conditions such as coronary heart disease, diabetes and high blood pressure.

Research published in The Lancet on March 11, 2020 shows the mortality rate in patients with COVID-19 is higher among elderly people with these pre-existing chronic diseases.

The high prevalence of chronic disease such as coronary heart disease (1.5% of the Indonesian population in 2018 or 4 million individuals), diabetes (1,5% or 4 million) and high blood pressure (34% or 60 million of >18 years old population) can increase the risk of death in people with COVID-19.

More accurate calculation of the COVID-19 fatality rate

To have a more accurate picture, calculating the percentage of deaths should also take into account the diagnostic delay – the length of elapsed time from the date the specimen was taken to the date the laboratory examination was carried out.

The longer the delay of diagnosis, the more positive cases there are that aren’t reported at the time of death rate calculation. So, the percentage of deaths will tend to be higher if this factor is not taken into account.

Additionally, to be able to identify the percentage of pure COVID-19 deaths (without accompanying illnesses), it is necessary to distinguish between the calculation of death in the elderly with the young and differentiate the mortality rate in cases that have accompanying illnesses with those that do not.

Henry Surendra, Postdoctoral fellow (Epidemiologist), Eijkman-Oxford Clinical Research Unit (EOCRU)

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