Omicron replicates 70 times faster than delta in airways, but lung infection appears less severe

The Covid-19 Omicron variant spreads or replicates faster in human airways than delta but has less severe impact on the lungs compared to the original virus strain.

This is based on a study published by researchers at Hong Kong University’s Faculty of Medicine.

Dr Michael Chan Chi-was and a team of researchers discovered that the variant replicates much faster in the bronchus, which connects the windpipe to the lungs, after 24 hours of infection.

However, they said it reproduces 10 times slower in the actual human lungs tissue.

The study’s findings said the variant’s rapid replication in the airway may explain why it transmit faster than past Covid-19 variants but the lower infection in the lungs may indicate it causes less severe impact.

“It is important to note that the severity of disease in human is not determined only by virus replication but also by the host of immune response to the infection,” Chan said in a statement this week.

Chan also not that a highly contagious virus like omicron could cause more severe disease and death simply by spreading faster despite showing less serious affects to the lung.

“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,” he added.

In another update, CNBC news reported that the White House chief medical advisor Dr Anthony Fauci on Wednesday, cited data from South Africa, that omicron reduces the protection of Pfizer and BioNTech’s two-dose vaccine against infection to 33 per cent, compared to 80 per cent protection before the variant emerged.

However, he said the two-dose vaccine was still 70 per cent effective at preventing hospitalisation, Fauci.

He added that Pfizer’s booster dose provides 75 per cent protection against symptomatic disease, citing data from the United Kingdom Health Security Agency.

The World Health Organisation (WHO) on Tuesday said omicron spreading faster than any previous Covid-19 variant.

WHO cautioned against treating omicron as a mild strain as it could increase transmission and lead to more hospitalisations thus burdening already strapped health-care systems.