Covid-19: What does 'flattening the curve' mean?


  • Malaysia
  • Sunday, 22 Mar 2020

Asking people to work from home and closing schools are part of the mitigation phase of a pandemic, which Malaysia is now experiencing. — YAP CHEE HONG/ The Star

With 553 cases as of March 16 (2020) noon and an unprecedented jump from 41 new cases on March 14 (2020) to 190 new cases on March 15 (2020), the Government issued the movement control order (MCO) on March 16 (2020) with the sole intention of slowing down the spread of Covid-19.

Although this is going to cause great inconvenience to the public and a huge economic loss to the nation, there is simply no choice, as we have to reduce the number of new cases quickly.

Any outbreak of an infectious disease has a ramping-up period, followed by a peak of intensity, then a decline, giving a bell-shaped curve (See graphic below).

The height of the curve is the maximum number of cases resulting from the infection and this number may well be above what the healthcare system in any country can cope with.

Malaysia is presently at the ramping-up stage and we do not know when the peak will be reached.

However, before that happens, we must do everything we can to “flatten the curve”.

The main aim of “flattening the curve” is to prevent a sharp peak of cases and spread out the infection over a longer period of time so that the healthcare system will not be overwhelmed.

The number of new infections may not be reduced significantly overall, and there is even the possibility of the pandemic lasting slightly longer.

It is a delicate balance of managing the pandemic with limited resources for critical patient care.

With only about 1,000 adult ICU (intensive care unit) beds in the country, we will definitely find it hard to cope with the increase if Covid-19 is allowed to peak in a short time.

Even now, without Covid-19, public hospitals are already stretched with ill patients needing ventilators, according to senior consultant paediatrician Datuk Dr Amar Singh HSS.

Thankfully, the Government is going to buy more ventilators in anticipation of a surge in Covid-19 patients.

Using mathematical modelling of epidemics can help in defining the features of a particular spread of infection.

Studies in Wuhan, China, and elsewhere showed that the average reproduction number (Ro) of Covid-19 is about 3.

This means that three persons can be infected by one contact case with Covid-19, as compared to the annual influenza with an Ro of just over one.

Should Ro be above one, the infection is expected to spread, while at values less than one, an infection can be expected to fizzle out.

What we need to do to stop the pandemic is to reduce the Ro to below one by breaking the chain of transmission so that patients are not infecting others.

Basically, this can be accomplished by social distancing through containment and mitigation – two well-tried public health methods that worked with SARS (severe acute respiratory syndrome), MERS (Middle East respiratory syndrome) and influenza A(H1N1).

Containment involves the rapid identification of cases, placing infected persons in isolation and contact tracing so that contacts of an infected person can be put under observation.

Containment works well if the number of cases are manageable and healthcare services are able to cope with contact tracing.

However, when we have an incident like the Masjid Jamek Sri Petaling tabligh gathering, where there were about 16,000 people, including 1,500 foreigners involved, this will be very tough to manage.

The Health Ministry has classified the current situation as a late containment phase.

However, we are now moving into the mitigation phase where schools and other educational institutions are closed; travel restrictions enforced; all government and private premises are closed, except those involved in essential services; and people are asked to work from home.

Of course, everyone wants to know how long the pandemic will last and how soon the MCO can be lifted, so that life can return to normal.

After all, daily paid workers in particular need their pay cheque.

China has shown us that aggressive methods like locking down millions of people can reduce the number of cases from tens of thousands to a mere two digits a day in just three months.

We have the means and the tools, as well as political commitment, but do we have the determination?

This is the time for people to make personal sacrifices for the greater good.

It is not easy to live with social distancing and social isolation, as humans are basically social creatures.

However, we are living in difficult times and we need to make hard decisions, like cancelling events, trips, and even weddings.

As a collective society, we need to band together in an effort to protect our communities.

This pandemic can only come to an end if we individually intervene and make a difference together.

We cannot afford not to!

Emeritus Professor Datuk Dr Lam Sai Kit is an Academy of Sciences Malaysia senior fellow and Universiti Malaya research consultant. For more information, email starhealth@thestar.com.my. The information provided is for educational purposes only and should not be considered as medical advice. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.

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