KUALA LUMPUR, July 8 — An asymptomatic Malaysian man tested positive for the coronavirus on a PCR test in Sibu, Sarawak, despite testing negative on an antigen rapid test earlier here.
Sarawak’s Patient 573 was one of five Covid-19 cases in the state who tested negative on antigen rapid tests at the Kuala Lumpur International Airport (KLIA), but subsequently tested positive on the rT-PCR test upon landing in Sarawak, according to Sarawakian authorities.
The Sarawak Disaster Management Committee (SDMC) said today that the latest case was an engineer working at an oil and gas company in Saudi Arabia who returned to Malaysia on July 3 and underwent a Covid-19 antigen rapid test kit (RTK) at KLIA that day, with a negative result.
The Malaysian stayed overnight at Tune Hotel KLIA and flew to Sibu on an AirAsia flight on July 4, after which he was taken to a quarantine centre in the Sarawak city.
He was swabbed on July 6, with the rT-PCR test, the gold-standard test for the coronavirus, from the Sibu Hospital laboratory indicating a positive result on July 7.
“The case did not show any sign or symptom of Covid-19 and has been admitted to Sibu Hospital on July 7, 2020 for further treatment,” SDMC said in a statement today.
It is unknown if the antigen rapid test at KLIA yielded a false negative result for Sarawak’s Patient 573, or if he had contracted the novel coronavirus in the three days between landing at KLIA and Sibu. But the occurrence of five Covid-19 cases in Sarawak, including Patient 573, undergoing the same experience indicates possible inaccurate results from the antigen RTK being used at KLIA.
Antigens are viral proteins expressed only when the virus is actively replicating, so tests based on antigen detection can identify acute or early infection. PCR tests also detect active infection of SARS-CoV-2 and hence, are used to diagnose Covid-19, the disease caused by the virus. The antigen RTK, however, has a much quicker turnaround time at just minutes, whereas the PCR test takes 24 to 48 hours to yield results in the lab.
The Star reported recently the Ministry of Health (MOH) as saying that returnees from abroad are required to get tested for Covid-19 through the antigen RTK, except for those with a negative result from a prior PCR test. Malaysians will be charged RM60 for the antigen RTK (RM120 for foreigners), less than half the price of the PCR test at RM150 for Malaysians and RM250 for foreigners.
Veteran physician Dr Milton Lum previously wrote in his column on CodeBlue that PCR tests, which are used globally, have sensitivity and specificity of 90 per cent or higher. This means that 90 per cent or more of those who test positive truly have the SARS-CoV-2 virus and that 90 per cent or more will not slip through as a false negative.
With the new Covid-19 case in Sibu, Sarawak has confirmed a total of 573 coronavirus cases. Five Covid-19 patients are still being treated in hospital, all of whom are Sarawakians who recently returned from abroad and have been quarantined at quarantine centres.
SDMC revealed that all five cases had previously tested negative on the antigen rapid test at KLIA, but later tested positive on the PCR test upon landing in Sarawak.
The five patients comprised one in Miri who returned from Tunisia, two in Bintulu who came back from Mexico and the United Kingdom, and two in Sibu returning from the United Kingdom and today’s case from Saudi Arabia.
“Therefore, SDMC wants to stress that it is compulsory for those returning overseas to undergo PCR tests upon arrival and to be quarantined until they test negative, before they can be allowed to be quarantined at home. A second sample will be taken from them on Day 10,” SDMC said.
According to SDMC, Kuching’s status has now turned from yellow to green, which means the state capital has been free of new Covid-19 cases in the past 14 days. The classification excludes imported cases from overseas.
End Of Sri Petaling Cluster
MOH separately announced today the end of active cases in the Sri Petaling cluster, the biggest Covid-19 cluster in the country, that saw a reported 3,375 cases, accounting for 38.9 per cent of Malaysia’s total coronavirus cases. The majority, or 64.8 per cent, of the Sri Petaling cases did not display any symptoms.
A total of 34 deaths were reported in the cluster that was sparked from an international tabligh gathering of 16,000 people at the Sri Petaling mosque in Kuala Lumpur from February 27 to March 3.
Cases in the cluster were detected in seven states in Malaysia, infecting 2,550 Malaysians and 825 foreigners from 28 countries.
According to MOH, the first Covid-19 cases from the tabligh cluster were reported on March 11 — Patients 131 and 136 who were Malaysians from Pahang and Negri Sembilan that attended the religious gathering.
“This cluster most probably originated from overseas and later spread in the community through mass gatherings and close contact with positive cases. The transmission of Covid-19 from this cluster spread throughout the entire country of Malaysia.”
MOH also reported three new Covid-19 cases today comprising Malaysians who acquired the infection from overseas. The total coronavirus cases in Malaysia has hit 8,677, whereas there are 70 active cases.
No new death from Covid-19 was reported, leading to a total of 121 fatalities from the virus in the country.