KUALA LUMPUR, Sept 18 — A medical expert has disputed claims that a Public Works Department (JKR) engineer may have contracted Covid-19 upon landing in Kuching, Sarawak, when she tested positive on a test taken minutes after getting off her flight.
Former immediate Sarawak Malaysian Medical Association (MMA) chairman Dr Morni Abu Samat said it is “impossible” for a person to test positive on an RT-PCR test taken just minutes after getting infected by the coronavirus.
He also believes the JKR employee might have been infected in Kuala Lumpur before she flew to Kuching.
“We estimate the incubation period — two weeks’ history,” Dr Morni told CodeBlue.
The incubation period for Covid-19 — which is the time between exposure to the virus, or getting infected, and symptom onset — can be up to 14 days, though, according to the World Health Organization (WHO), the average is five to six days. Studies show that the viral load of SARS-CoV-2, the virus that causes Covid-19, peaks around the time symptoms show or a few days after.
The newly reported Covid-19 case yesterday of the JKR engineer — who tested positive in Kuching after flying from Kuala Lumpur — has left the public in confusion, as both federal and Sarawak state authorities did not classify her as a local case either in Kuching or Kuala Lumpur, according to their 14-day moving charts of new local infection within the past 14 days. Both Kuala Lumpur and Kuching officially remain green zones, free of new local coronavirus cases reported within the past fortnight.
The Ministry of Health (MOH) suspects that the JKR engineer had contracted Covid-19 in Kuching, while the Sarawak state government claimed she was infected before entering the state.
Sarawak Minister for Local Government and Housing Dr Sim Kui Hian said Sarawak’s State Disaster Management Committee (SDMC) simply reported what was advised by the Sarawak state health department, which is under the federal MOH.
“The same agency also reports to MOH. It is very strange for different departments within MOH to have very different interpretations, leaving us wondering which of the departments in the MOH is competent,” Dr Sim, a cardiologist, told CodeBlue.
Former MMA president Dr Milton Lum said the likelihood of getting a Covid-19 infection depended on the infected person’s viral load and the duration of one’s exposure to that infected person.
“The officer could have got the infection in KL, Kuching, and on the flight to Kuching,” Dr Lum told CodeBlue.
MOH yesterday classified the JKR Malaysia employee — who is from Cheras, Kuala Lumpur — as a local Sarawak case, identified through screening at Sarawak’s international gates, according to Health director-general Dr Noor Hisham Abdullah’s statement. The Sarawak state government, however, has classified Patient 701 as an imported case (Sarawak uses its own Covid-19 patient designation separate from MOH).
“However, there is no information provided on the accuracy of the RT-PCR tests in Kuching and in Kuala Lumpur. No information about the number of samples taken for testing in Kuching and Kuala Lumpur,” Dr Lum said.
“The public may recall that there have been instances when the RT-PCR tests on passengers were negative at KLIA but positive at Kuching airport.”
It is to be noted that SDMC has highlighted several Covid-19 cases which previously tested negative on the antigen rapid test at the Kuala Lumpur International Airport (KLIA), but later tested positive on the gold-standard RT-PCR test upon landing in Sarawak.
Dr Lum mentioned that contact tracing among close contacts of the JKR engineer may help the authorities to figure out the source of Covid-19 infection, which may eventually provide an answer to where possibly she contracted the virus.
“Contact tracing and testing of the officer’s contacts, which could include genetic analysis, would provide an answer as to where she got the infection,” Dr Lum said.
At the same time, Dr Lum also emphasised that it cannot be assumed that an asymptomatic person is less infectious, as there are reports of superspreaders who were asymptomatic persons. SDMC said yesterday that the JKR engineer did not show symptoms of Covid-19.
Dr Morni stated that the higher the cycle threshold (Ct), the lower the viral load and the infection is less contagious.
Based on a study conducted in South Korea, when the Ct value of a specific gene is lower, it means there are more genes existing in the sample. However, there is no fixed or permanent Ct cut-off value. It varies based on each diagnostic reagent, even for the same gene.
“We have this Ct value noted in the result. It means that if there is a high Ct value, the number of cycles carried out to replicate the DNA of the virus until it is detectable, less likely to be infectious based on available PKB (pejabat kesihatan bahagian) data. If the Ct value is more than 30, there is no public health evidence of spread,” Dr Morni said.
Yesterday, at the time MOH reported the daily Covid-19 cases in the country, mySejahtera’s hotspot tracker says that no Covid-19 cases have been reported within a 1km radius in the last 28 days in any of the locations that JKR said its infected employee had visited, nor in Cheras, where she was said to come from, or JKR’s headquarters in Kuala Lumpur. The MOH coronavirus management app lists cases in its hotspot tracker based on the possible source of infection and areas where infection persists.
“This particular case illustrates the weakness of MySejahtera in which the operator is also providing the oversight. The information uploaded on MySejahtera is done by Health Ministry staff. It is essential for public trust that there is external oversight of MySejahtera,” Dr Lum said.
At the same time, Dr Morni highlighted the possibility that the infected staff did not register herself using the MySejahtera application.
Before attending a meeting at JKR Sarawak in Kuching on September 14, the staff had also attended a Dewan Negara sitting in Parliament and a meeting at the Works Ministry’s office at Kerja Raya Complex in Jalan Sultan Salahuddin, Kuala Lumpur, on September 10.
Dr Morni stated that it is not necessary for all the senators who visited Parliament on September 10 to be tested for the coronavirus.
“No need. If mask, social distancing etc is practiced, it is less likely to spread. New norms drastically reduce risk of transmission,” Dr Morni said.
In contrast, Dr Lum stressed that all the possible close contacts of the patients should be tested for the virus, including the senators.
“All contacts of the officer, including passengers and crew on the flight to Kuching, should be identified and informed so that they are vigilant and can seek medical attention early, if necessary. The testing of all senators, on the day she attended the Dewan Negara, should be according to MOH’s standard operating procedures (SOP).”