PETALING JAYA, August 3 (Sin Chew Daily) — Local virologist Prof Emeritus Datuk Dr Lam Sai Kit says the Delta variant can stay in the air much longer and can spread without a person coming into contact with an infected individual.

He also says the three to six feet social distance may not have too much effect in fending off the Delta variant.

"In a suitable environment, it can spread to more people. Its high infectivity is related to aerosol transmission, and can stay in the air and a contaminated surface for much longer time."

Dr Lam  said during an interview with Sin Chew Daily that the Delta variant can cause more severe infections than SARS-CoV-2.

Luckily, he said vaccinated individuals can avoid severe illnesses while the unvaccinated may suffer severe illnesses or even death with a mortality rate ten times as high.

He also said Delta variant can spread through a fully vaccinated person who presents very mild or even no symptoms (phases 1 and 2).

"Study shows that a vaccinated or unvaccinated person infected with the Delta variant carries up to 1,000 times more virus particles in his nose and throat than a SARS-CoV-2 carrier.

"Although the progress of vaccination has been very encouraging, we are now dealing with a variant that could give rise to breakthrough infection. It's not time to let down our guard.

"Due to sharp increase in cases involving the Delta variant, the US Centers for Disease Control and Prevention (CDC) has reversed its decision on mask wearing. Even fully vaccinated people should now put on a face mask in an indoor environment or highly infective community.

"We hope to achieve at least 80% herd immunity within shortest time possible to prevent further mutation of the virus. We've heard of new variants such as Delta Plus and Lambda, and we hope they will not come into the country before we have sufficient herd immunity.."

Meanwhile, Universiti Malaya public health expert Dr Victor Hoe said we used to think that the virus spreads through normal activities such as droplets and coughs, or in an aerosol-generating procedure (AGP) by medical personnel, but now the virus can spread easily in the air or through the aerosol.

He insisted that adequate ventilation is of tremendous importance in controlling the spread of the virus and members of the public should avoid closed and poorly ventilated indoor spaces, adding that a person staying together in a room or workplace over a long period of time can now be deemed a "close contact", especially if one of them does not put on a face mask.

Associate Prof. Dr. Chan Yoke Fun, Head of Medical Microbiology Department of Universiti Malaya, told Sin Chew Daily statistics show that the Delta variant is 40-60% more infective than the Alpha variant, and almost twice as infective as the SARS-CoV-2 original strain.

Additionally, more virus particles have been discovered in the respiratory tract of a person infected with the Delta variant.

A study conducted in China shows that the quantity of virus in a person infected with the Delta variant is up to 1,000 times higher than in a person infected with the other COVID-19 variants, while WHO has warned that the Delta variant is the "fastest and fittest" coronavirus strain so far.

Dr Chan pointed out that while most vaccines are still effective against the Delta variant, the problem is, it also transmits the fastest.

She said the CDC has now proposed that even fully vaccinated people should put on face masks in the public.

Once the economy opens up again, Malaysians should know clearly how the virus spreads and those who have not yet been immunized must go for vaccination as soon as possible while those who have been vaccinated must continue to adhere to all the SOPs.