Lessons from the Lab: SARS-CoV-2 Detection Rate amongst the Vaccinated Travel Lane and Non-Vaccinated Travel Lane Travellers into Malaysia

BACKGROUND: The vaccinated travel lane (VTL) between Malaysia and Singapore was implemented to facilitate travelling between countries without the need for quarantine. OBJECTIVES: i) Observe the rate of positive SARS-CoV-2 test results amongst inbound international travellers; ii) Explore possible factors associated with the outcome of test results between VTL and non-VTL travellers. METHOD: This is a retrospective cross-sectional study involving air travellers arriving in Malaysia via the Kuala Lumpur International Airport (KLIA) or Kuala Lumpur International Airport 2 (KLIA2) who were tested for SARS-CoV-2 by reverse transcriptase polymerase chain reaction (RT-PCR) from 29 November 2021 to 15 March 2022. Subject demographics and RT-PCR results were retrieved from the laboratory information system and statistically analysed. RESULTS: Out of 118,902 travellers, mostly were Malaysian nationals (62.7%) and VTL travellers (68.2%) with a median age of 35 years old. A total of 699 (0.6%) of travellers tested positive on arrival, out of which 70.2% had cycle threshold (Ct) values > 30 (70.8% of VTL and 70.0% of non-VTL cohorts). Non-VTL travellers were 4.5 times more likely to test positive compared with VTL travellers (1.25% versus 0.28%; P < 0.001). CONCLUSION: Tighter entry requirements including vaccination status and testing frequency, the use of sensitive detection methods on arrival and similar public health policies between countries may have contributed to the VTL being a safe and cost-effective mode of travel.