What makes Omicron more infectious, new study provides possible answer

A new study has partially uncovered a major characteristic about Omicron previously unknown to scientists, however, it’s not all good news.

A new study has uncovered why the Omicron variant may be considerably more transmissible but cause less severe infections in patients.

Preliminary research from the LKS Faculty of Medicine at The University of Hong Kong found that the virus multiplies faster in the bronchus (the tube that carries oxygen between your trachea and the air passages in your lungs) than the lungs.

Comparisons between the original Covid, Delta and Omicron strains found that Omicron infects and multiples 70 times faster than the Delta variant and original Covid strain, however it also multiples 10 times lower in the lungs than the original strain.

Researchers said this may suggest why Omicron “transmits faster between humans than previous variants,” while also boasting “lower disease severity”.

Researchers found Omicron to multiple faster in the bronchus than the lungs. Picture: LKS Faculty of Medicine at The University of Hong Kong.

Despite this, the study also states the severity of the virus is dependent of the host’s immune response, said Associate Professor, School of Public Health and Principal Investigator, Dr Michael Chan Chi-wai.

While Omicron might be less severe for healthy people, it can still severely effect and be deadly in patients with compromised immune systems and comorbidities like diabetes, cancer or hypertension.

Omicron: The transmissibility / severity debate

While scientists have long suspected that Omicron’s virility is less severe than the Delta strain, more research is needed especially when it comes to concluding whether more infectious strain can outweigh the benefits of a less severe variant.

This comes as a study released on Tuesday found that Omicron was four-times more infectious than the original Covid strain and two-times more infectious than the Delta strain.

Scientists said this was because Omicron’s highly-mutated spike protein was better at binding to human cells, which then infects the host with Covid.

The mutated-strain also showed “remarkable” signs to “escaping vaccine-induced” immunity.

“In addition, we find Omicron pseudovirus is significantly more infectious than any other variant tested,” read the abstract of the study.

An infectious diseases and virology expert from the UK’s University of St Andrews, Muge Cevik said it’s still to too early to tell the potential impact of an Omicron outbreak.

“For those asking whether this is good/bad news, simple answer: I don’t know,” she wrote on Twitter.

“While Omicron may infect the lung cells less efficiently, a higher viral load may worsen immune response.”

Important finding from Hong Kong: SCoV2 Omicron replicates to higher initial levels than earlier variants in bronchial tissue. Slightly decreased replication in lung tissue. Might entail higher levels of virus shedding, even if bronchus ≠ nose or throat.https://t.co/hLw4dp7yD8pic.twitter.com/CbgFvs5om5

— Christian Drosten (@c_drosten) December 15, 2021

Dr Chan also warned that despite its milder symptoms, Omicron will likely still have a “very significant” impact on the trajectory of the pandemic.

“It is also noted that, by infecting many more people, a very infectious virus may cause more severe disease and death even though the virus itself may be less pathogenic,” Dr Chan said.

“Therefore, taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection, the overall threat from Omicron variant is likely to be very significant.”