[EXPERT REACTION] What makes COVID-19 so dangerous?

As the number of COVID-19 cases continue to rise worldwide, we asked experts on the risks and dangers of the virus:

“What makes COVID-19 so dangerous?” 

EXPERT REACTION

Dr Taznim Begam Mohd Mohidin, Virologist & Senior Lecturer at the Institute of Biological Sciences, Faculty of Science, University Malaya, said: 

“COVID-19 is a threat due to many reasons. The current fatality rate of COVID-19 is estimated to be about 4% and this means that COVID-19 is so much more deadlier than the seasonal flu. 

An infected person who does not show any symptom is able to pass on the virus to another person from the time he is infected until he is fully cured. Also, an infected person will only be tested if he shows symptoms or if the person had close contact with a diagnosed person. This lengthens the time taken to identify and isolate COVID-19 cases before they spread the virus to others.

Currently, there is no drug to effectively treat COVID-19. Vaccine to provide protection against COVID-19 infection is being developed and may be ready in 12 months.”

Dr Jasmine Khairat, Virologist & Senior Lecturer at Institute of Biological Sciences (ISB) Faculty of Science in the University of Malaya, Kuala Lumpur, said:

“The symptoms will be somewhat similar to seasonal flu but its mortality rate as we can see now is much more dire ~4% whereas flu is typically 0.1%. The fact that it is highly infectious, a relatively new strain of virus we have not seen in humans before, able to infect 3 times more people than normal flu, as well as the lack of understanding of the virus makes it dangerous but less so than SARS and MERS.

Dr. Ng Siew Kit, Biochemist & Senior Lecturer at the Advanced Medical and Dental Institute, Universiti Sains Malaysia, said: 

“SARS-CoV-2 (the virus) has several characteristics that fit the bill of a “perfect” virus in this century. That was the reason why WHO and scientists urged strong armed handling even at the early stage of the outbreak.

Aerosol-borne – The major transmission route through aerosol droplets is particular efficient in high-density population

Direct human transmission – Very hard to “break the transmission chain”, as it is much harder trying to control human movements

Long incubation period – At least 14 days or even longer days for viral spread unwittingly

Asymptomatic carriers – Not all infected showed symptoms meant that we will not be able to totally isolate and treat the infected.

No herd immunity – Being a new virus, very few people on Earth have the immunity against SARS-CoV-2. Therefore, everyone can get infected.

Mutation rate – RNA viruses tend to have higher mutation rates compared to DNA viruses, and other pathogens in general.

However, not all hope is lost. SARS-CoV-2 has relatively low mortality when compared to SARS and MERS, of the same coronavirus family. Also, research from earlier SARS and MERS outbreak meant that the scientific community did not start from scratch. Many governments and their advisors have also learned from earlier experiences to better handle virus outbreaks.”

Dr Tan Cheng Siang, Virologist & Head of Centre for Tropical and Emerging Diseases, Faculty of Medicine and Health Sciences, University Malaysia Sarawak, said: 

“SARS-CoV-2 was initially called the novel Coronavirus – 2019 (nCoV-19) which means it was newly discovered. Since it is new, our immune system does not have any immunity against the virus and at the same time overreact, causing the cytokine storm phenomenon, which is often linked to systemic multi-organ failure, pneumonia and eventually death.  

Coronavirus has short protrusions from its body called the spike. The spike acts as a key and the virus can only infect cells which the key can open. Most of the time, the virus keeps itself in a narrow range of animal species as the key cannot open the lock on human cells, preventing the animal-to-human transmission. However, coronavirus is an RNA virus which mutates regularly. Any changes to the gene coding for the spike will be reflected by a micro-structural change to the spike. 

By chance, this new key may be able to open the lock on human cells and cause a zoonotic infection. Zoonoses is a jargon to describe the transmission of animal viruses to humans and vice versa. Changes to the spike is like the duplication of a master key, a perfectly duplicated master key can all locks of the same model causing a sustainable human-to-human transmission, but a poorly duplicated key may be able to only open a limited number of locks causing a non-sustainable human-to-human transmission. 

SARS-CoV-2 which causes COVID-19 is a relative of SARS-CoV-1 which had caused the Severe Acute Respiratory Syndrome (SARS) epidemic back in 2002/03. SARS-CoV-1 has an imperfect key which can open a limited number of locks on human cells. It had caused severe infection in a significant number of victims and killed about 11% of them, limiting its spread. 

SARS-CoV-2 is different. It seems to have the perfectly duplicated master key to open the lock on all humans. The ability to cause asymptomatic infection (no sign of sickness) to mild disease indistinguishable from common cold enables the virus to spread rapidly in stealth. Unfortunately, some infected patients with other underlying health conditions developed severe infection.”

Disclaimer: Science Media Centre Malaysia has collected these comments to provide journalists with a range of expert perspectives on the subject. The views expressed here are personal opinions of the experts. They do not in any way reflect the views of the Science Media Centre or any other organization unless specifically stated.

**You can view all previous posts about COVID-19 here: https://sciencemediacentremalaysia.com/tag/covid-19/