[EXPERT REACTION] Can you get COVID-19 twice?

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One of the most concerning issues with the COVID-19 outbreak is whether those who have had it the first time risk infection a second time and how does it impact their immunity. We asked experts: 

“Can you get COVID-19 twice?”


Associate Prof. Dr. Chan Yoke Fun, Virologist & Senior Lecturer at the Department of Medical Microbiology, Faculty of Medicine, University of Malaya, said:

“We don’t know yet. Some reports from China reported re-infection. There are not enough evidences to prove this. The viability of SARS-CoV-2 detected by Real-time RT-PCR (qRT-PCR) in this patient has not been proven by viral culture. In this case, the virus RNA persists, but the virus is not actively replicating.

A study showed three rhesus macaques did not develop a second infection after recovering from a first exposure to the SARS-CoV-2 and being re-exposed to coronavirus, suggesting that primates are capable of developing protective immunity to the virus.”

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

“Similar like any respiratory virus, anybody with past infection with SARS-CoV may be susceptible to re-infection. Previous study has shown that immune protection for human coronaviruses is short—lived and there is a risk for reinfection among previously exposed populations. However, available scientific evidence has not confirmed that there is a risk of reinfection with SARS-Cov-2, the virus that causes COVID-19.”

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

“This question arose after news reports of reinfection cases in Japan and China. We have to bear in mind that these are news reports and there are speculations whether the patients were truly re-infected or they did not fully recover or whether there was a mistake in one of the tests. 

Scientific studies are needed to confirm whether these claims are indeed true. Tests results are not necessarily accurate and this is why doctors perform tests multiple times to be sure of a result. Studies are needed to check if these patients were really re-infected with the virus or the infections simply persist. 

According to Nobel Laureate Peter Doherty, an infected person is most likely to develop immunity to COVID-19, making re-infection (at the moment) unlikely. It may be more likely that the test results that showed that the patients were clear of the virus were wrong. This may be because the swab was taken at the part where the virus was not detected but instead the virus is deeper in the lungs.

Studies show that there are currently two different versions (strains) of SARS-CoV2 that are circulating. However, this does not mean that these two strains are so different that a person’s immunity to one version cannot confer protection to another version. 

There is much to learn about the novel coronavirus and hence, it is not surprising that for now, information will be changing quickly until we clearly understand the virus.”

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 killed about 4% of those who have been diagnosed with the infection. To look at the bright side, about 96% of the patients recovered and they will be immune to reinfection by the current SARS-CoV-2. Blood obtained from recovered patients has antibodies which can kill the virus and blood transfusion of this sera seems to help COVID-19 patients to recover. We can get the second infection by SARS-CoV-2 only if the virus mutates significantly so that our current immunity cannot kill the updated virus. However, if that happens, past infection does offer some protection against developing severe disease.”

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. 
Bionotes of experts

Associate Prof. Dr. Chan Yoke Fun is a virologist focused on the epidemiology and pathogenesis of enterovirus A71, an emerging virus that causes severe neurological disease. She leads a laboratory with research interests in epidemiology and pathogenesis of emerging viruses such as enterovirus A71, chikungunya, and respiratory viruses. Dr. Chan also served as an Associate Editor of BMC Infectious Diseases and guest editor in PLOS Neglected Tropical Diseases. She has multiple joint publications with collaborators from Asia, Europe, and the USA. With more than 20 years of research experience, she has over 80 publications, her studies have led to a better understanding of how viruses spread and infect humans.

Dr Jasmine Khairat received her PhD and virology training from Monash University Malaysia. Currently, she is a senior lecturer at Institute of Biological Sciences (ISB) Faculty of Science in the University of Malaya, Kuala Lumpur, Malaysia and has been teaching Microbiology courses. Her researches include host-pathogen interactions, virus surveillance, emerging infectious diseases and antiviral studies involving respiratory viruses specifically influenza virus to improve our knowledge in viral pathogenesis.

Dr Tan Cheng Siang is the Head of Centre for Tropical and Emerging Diseases, Faculty of Medicine and Health Sciences, University Malaysia Sarawak. A trained virologist, he has more than 20 years experience in handling infectious viruses, virus isolation and identification, phylogeny, molecular epidemiology, recombinant protein expression and diagnostic tool development. He is also a certified biosafety officer and holds four Certified Professional credentials from the International Federation of Biosafety Associations (IFBA). 

Dr Taznim Begam Mohd Mohidin is a virologist and is currently a Senior Lecturer at the Microbiology Program, Institute of Biological Sciences, Faculty of Science, University Malaya. She received her BSc (Hons) in Microbiology and MSc in Molecular biology from Universiti Putra Malaysia, with research works focusing on Nipah virus. The role of viruses in cancers sparked her interest to pursue her PhD in University Malaya, in which she studied the effects of viral gene silencing in Esptein-Barr virus-associated cancer cells. Dr Taznim’s research interests are in the fields of virology and immunology, particularly on influenza virus, Epstein-Barr virus and innate immunity which includes antiviral defense and inflammation.

**All previous posts about COVID-19 here: https://sciencemediacentremalaysia.com/tag/covid-19/

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