Increasing Sporadic Covid-19 Cases: Should We Heed Airborne Transmission Of SARS-CoV-2? — Ahmad Mahfuz Gazali

Clear guidance about the importance of moving activities outdoors, improving indoor air using ventilation and filtration, and improving protection for high-risk workers must be considered as public health measures.

On May 11, 2021, Health director-general Dr Noor Hisham Abdullah reported that 80 per cent of new Covid-19 recorded in the country had been sporadic infections. To date, Malaysia has reported more than 470,000 cases, and is now facing the third wave, with a daily rate of infection numbering in the thousands.

A national Covid-19 immunisation programme was initiated and launched on February 24, 2021. To date, 3.7 per cent of the Malaysian population has received at least one dose of the Covid-19 vaccine, while 2.3 per cent has been estimated to have completed two doses of vaccination.

However, despite the rollout of the Covid-19 vaccine nationwide, Malaysia has been recording a steep increase in new infections since April 13, 2021. Moreover, the variant of concern (VOC) of the virus in Malaysia has been reported in our country.

Its spread in the community has been identified by genome sequencing performed by the Institute for Medical Research Malaysia (IMR). Our country has already reported the presence of the UK, South Africa, and Brazil VOC. More recently, the Indian variant of the SARS-CoV-2 virus was detected in travellers returning from a humanitarian mission to India.

The steep increase in positive cases and the presence of the VOC in our country has prompted the Malaysian government to take swift action. Accordingly, prime minister Muhyiddin Yassin announced a third nationwide Movement Control Order (MCO), running from May 12 to June 7, 2021.

Under this MCO, all educational institutions will be closed, and social visitations and sports and recreational activities are banned, except for open area exercise. In addition, the government also banned inter-district and interstate travels, with certain exceptions. This decision was made days before the Hari Raya celebrations to prevent a sharp increase of new infections.

This brings us to the most critical question — have we failed to adhere to the SOPs? Are the present SOPs not stringent enough? One of the most compelling theories is that the SARS-CoV-2 virus can be transmitted via the airborne route.

On April 15, 2021, a commentary was published in The Lancet about the airborne transmission of the SARS-CoV-2 virus. The article lays out ten scientific reasons in support of the airborne transmission of SARS-CoV-2.

This is not the first article that has been written about airborne transmission. A similar article was published in Science magazine on October 16, 2020, arguing that the virus may be transmitted through the air.

Why is airborne transmission crucial? Previously it was thought that the virus was transmitted in large droplets with a size of 100 µm or more. The large size of droplets will cause it to fall to the ground in seconds within two metres of the source.

Because of their limited travel range, physical distancing reduces exposure to these droplets. Based on this fact, physical distancing was formulated as one of the public health measures to reduce the transmission of the virus.

However, based on recent evidence, the virus can be transmitted via airborne transmission in aerosols. Viruses in aerosols (smaller than 100 μm) can remain suspended in the air for many seconds to hours.

More importantly, aerosols containing infectious viruses can travel more than two metres and accumulate in poorly ventilated indoor spaces, leading to super-spreader events.

In light of this new information, airborne transmission of the virus may be partly responsible for the steep increase of new Covid-19 cases, despite compliance with the SOPs.

In addition to existing mandates of practising the 3Ws (wash, wear, warn) and avoiding the 3Cs (crowded places, confined spaces, close conversation), clear guidance about the importance of moving activities outdoors, improving indoor air using ventilation and filtration, and improving protection for high-risk workers must be considered as public health measures to break the chain of transmission of Covid-19.

  • This is the personal opinion of the writer or publication and does not necessarily represent the views of CodeBlue.

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