Thursday, March 5, 2020

Lessons from published lab results on COVID-19 patients' samples in Singapore

Report by : Gan Yung Chyan
                 / KUCINTA SETIA

Image courtesy : Roslan Rahman / AFP via Getty Images

There are now laboratory research studies on many COVID-19 (covid, in short) patients' blood, stool and respiratory samples.

According to the article "Epidemiologic Features and Clinical Course of Patients Infected With SARS-CoV-2 in Singapore" by the National Centre for Infectious Diseases Director Leo Yee Sin and other experts, Singaporean lab research specialists have discovered the virus SARS-CoV-2 (covi, in short) in patients' blood, stool and respiratory samples but none in urine samples. The first 18 covid patients including 16 Chinese nationals and 2 Singaporeans are treated with liponavir-ritonavir, a drug that is traditionally used to treat AIDS.

Respiratory samples are obtained through nasopharyngeal swabs done on the back of the patients' throats and noses.

There are side effects on four out of five covid patients treated with liponavir-ritonavir such as nausea, vomiting and / or diarrhoea and there are "abnormal liver function test results" on three covid patients. Researchers note only one patient completed the 14-day treatment course as a result of these side effects.

Covi was detected in stool of 50 per cent of the patients and in whole blood 8 per cent of the patients.

Further, according to the article, the experts have found that covid and sars have similarities: 

1. The incubation period is similar. Patients develop pneumonia from the first week to the second week of onset.

2. Children are rarely infected. There are very mild symptoms of covid in 3 Singaporean patients aged 6 months, 1 year old and 2 years old.

However, experts also found that the amount of covi is not directly proportional to the severity of symptoms. In the early stage of infection, covid patients have the highest levels of viral content in the body when symptoms are minimal, and then gradually decrease, which is exactly the opposite in the development of sars.

Experts believe that this may be because the patient’s symptoms are not directly caused by the virus, but the body’s response to the virus. Therefore, when the body produces white blood cells to fight the virus, more symptoms will appear, such as cough, fever, etc., and covi is gradually decreasing.


The article also points out that the relationship between the amount of virus and the strength of infectivity needs further study. However, experts call for people not to take covi lightly when they have mild symptoms, and they should take active measures to prevent the spread of the virus such as washing hands diligently.

In addition, patients infected with covid may have mild symptoms, and may be asymptomatic. Asymptomatic transmission is the virus transmission method that everyone is most worried about.

Dale Fisher, chairman of the WHO Global Epidemic Alert Network, told the media that the covid patents' throats must have covi but if there were no symptoms, without coughing, the virus would be unlikely to spread. In other words, to spread covi widely, infected people must cough (make or spit out the virus).


This means that even if people who have just been infected with covid have a high amount of virus in their bodies, they may have low infectivity because they are asymptomatic. Unless it is due to a meal gathering or close physical contact, asymptomatic people are unlikely to spread the virus in the community.

The research article "Epidemiologic Features and Clinical Course of Patients Infected With SARS-CoV-2 in Singapore" is published by JAMA Journal, a US medical science journal and available online at the JAMA Network Coronovarius Research Center for perusal.

As of 6 March 2020, Singapore has 117 confirmed covid cases, among which seven patients are in critical condition. There are no deaths.

Refs : 

Epidemiologic Features and Clinical Course of Patients Infected With SARS-CoV-2 in Singapore, Leo Yee Sin etal., JAMA,
https://jamanetwork.com/journals/jama/fullarticle/2762688

New research: this type of person carries SARS-CoV-2 most (in Chinese)
https://www.ntdtv.com/b5/2020/03/05/a102792332.html

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