It was reported in the media today (3 Apr) that at least 10 people in Singapore have been infected with the coronavirus from those without showing any symptoms.
This startling fact was reported in a joint paper published on Wed (1 Apr), which was co-authored by Associate Professor Vernon Lee, director of communicable diseases at the Ministry of Health (MOH) and the US Centres for Disease Control and Prevention (CDC).
The study focused on the pre-symptomatic transmission of Sars-CoV-2, the COVID-19 virus. It uncovered cases in Singapore which people were infected by COVID-19 from others not showing any symptoms of the illness at the point of infection.
In such cases, temperature screening would be useless. In fact, these people without symptoms would not even know they were already carrying the virus. They would only realise after symptoms developed in them later. The study suggests there is a need for the government to account for such cases.
Excerpt of cases
In the study, the researchers examined all the COVID-19 infections in Singapore between Jan 23 and March 16 and found that of the 157 locally transmitted cases, 10 could be attributed to pre-symptomatic transmission. That is to say, people were being infected by those who felt well but were already carrying the virus inside them at the point of infection.
Three of the 10 studied were from the Grace Assembly of God and The Life Church and Missions Singapore cluster, and had attended church service on Jan 19 – the same day when a Chinese couple from Wuhan attended. The 2 PRCs did not show any symptoms at the time in the church service. One of the three, a 52-year-old woman, sat in the same seat that one of the PRC tourists had occupied earlier in the day.
In the Safra Jurong cluster, a 54-year-old woman who had been exposed to a confirmed case at the dinner on 15 Feb, attended the same singing class as another woman, 63, on 24 Feb. Both later were diagnosed with COVID-19. The 63-year-old woman was infected with the virus from the 54-year-old without showing any symptoms when they were together in the singing class.
Then there was a Filipino couple, a nurse and her husband who both work in Singapore and came down with COVID-19. The nurse works at the emergency department of Ng Teng Fong General Hospital (NTFGH) in Jurong. The nurse’s husband went to the Philippines on 23 Feb to visit a relative who came down with “pneumonia”. He returned back to Singapore on 2 Mar. The relative then passed away. The Filipino nurse reported onset of symptoms on 8 Mar. She was confirmed to have COVID-19 on the 10th while her husband was confirmed to have the virus on 11th. The man is thought to have passed the infection to his wife, before showing symptoms later.
In another case, a woman, 58, was exposed to a confirmed case on 27 Feb at a singing class. On 1 Mar, she attended a church service, and is thought to have infected a woman, 26, and a man, 29, who were seated one row behind her. The elderly woman later developed symptoms only on 3 Mar, 2 days after attending the same church service as the latter two.
In seven of the 10 cases, pre-symptomatic transmission exposure occurred one to three days before the source patient developed symptoms.
MOH reviewing stance on masks
Meanwhile, Director of Medical Services at the Ministry of Health (MOH), Kenneth Mak, told reporters at a COVID-19 media conference on Tue (31 Mar) that his ministry is looking at medical evidence “very carefully” and is conducting a review of its stance on masks.
“As far as masks are concerned, we are in fact in the process of continuing to review the data that’s available, both in the literature as well as the international experience,” Prof Mak said. He added that recommendations would be made after the review is completed.
Up to this point, the Singapore government has been clear on urging members of the public not to wear masks if they are well.
And with regard to the wearing of masks, PM’s wife, Ho Ching, recently wrote on her Facebook page saying that if two people meet and both wear a mask, it would reduce the risk of COVID-19 infections further (‘MOH reviews stance on masks while PM’s wife Ho Ching says make do with homemade ones‘).
“We don’t need a hospital-grade surgical mask for general public use, as the chances of meeting a really sick patient are low,” she said. “We should save the surgical masks for our healthcare workers.”
She then went on to tell a story that in the early 1900s, a Penangite doctor in China was pushing hard on having the healthcare team wear masks. All they had was a surgical gauze, which is quite porous, folded over a piece of cotton cloth.
Likewise, she asked Singaporeans to “make do” with homemade ones.
“So, we too can make do, and be the 1st line of defence by washing hands, keeping a safe distance, or use a mask as an added safe distance, so as to save our healthcare workers and not overwhelm them with too many patients too suddenly,” said Mdm Ho.