Omicron ‘grows 70 times quicker in airways but 10 times slower in lungs’, making it ‘more transmissible but less severe’

THE Omicron Covid variant multiplies 70 times faster than Delta in human airways but 10 time slower in the lungs, new research has found.

Scientists at the University of Hong Kong say the findings could indicate the disease is more transmissible but less severe, as it pushed daily infections in the UK to a record high.


Omicron ‘grows 70 times quicker in airways but 10 times slower in lungs’, making it ‘more transmissible but less severe’
People queueing up to be vaccinated in central London
Omicron ‘grows 70 times quicker in airways but 10 times slower in lungs’, making it ‘more transmissible but less severe’

As the new figures were announced, Boris Johnson ramped up his plea for Brits to get boosters and issued a call to arms for vaccine volunteers to help beat Omicron.

The PM said there were “signs of hope” that the renewed jab blitz was helping the national battle against Covid.

The new study – which is being peer reviewed – revealed the virus was capable of replicating far faster in the tubes attaching the windpipe to the lungs, known as the bronchus.

But it found it struggled to reproduce efficiently in lung tissue, which might be why some people experience cold symptoms but few cases become serious.

Despite that, the study’s lead professor Dr Michael Chan Chi-wai still warned that the “overall threat from Omicron variant is likely to be very significant”.

He said it is important to note “that the severity of disease in humans is not determined only by virus replication but also by the host immune response to the infection”.

“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,” he said.

For their study the researchers successfully isolated Omicron and used lung tissue to investigate the new mutation.

They compared Omicron with the original strain, and with Delta.

The researchers found Omicron “replicates faster than the original Sars-CoV-2 virus and Delta variant in the human bronchus”.

They said that 24 hours after infection, the Omicron variant “replicated around 70 times higher than the Delta variant and the original Sars-CoV-2 virus”.

“In contrast, the Omicron variant replicated less efficiently (more than 10 times lower) in the human lung tissue than the original Sars-CoV-2 virus, which may suggest lower severity of disease.”

Meanwhile, England’s top doctor has warned Omicron is not necessarily milder than previous strains of the virus as data from South Africa suggest.

Professor Chris Whitty attempted to dispel the myth that people will not be hospitalised with Omicron at Wednesday’s Downing Street briefing.

The chief medical officer for England said he wanted to put a “serious caution” on what appeared to be positive data that had emerged from South Africa.

The nation said hospitalisation with Omicron is 29 per cent lower compared to the other variants.

Whitty also warned people to go further than current restrictions by prioritising social gatherings that really mattered, “usually that is family”.

He even urged friends to meet outside if possible ahead of the Christmas period.

Huge queues formed once again at vaccination centres today as all over-18s also became eligible to book their third jab online.


Omicron ‘grows 70 times quicker in airways but 10 times slower in lungs’, making it ‘more transmissible but less severe’
Chris Whitty has warned against rushing to conclusions about the Omicron virus