(Adds South African health worker study, Greece, Italy)
* AstraZeneca, Novavax say their shots protect from Omicron
* UK data suggests fewer hospitalisations than from Delta
* Don't extrapolate from similar SAfrican data -African CDC
* WHO also urged caution about drawing firm conclusions
* Omicron has spread fast, many countries under new curbs
By James Macharia Chege and Josephine Mason
LONDON, Dec 23 (Reuters) - Two vaccine makers said their
shots protected against Omicron as UK data suggested it may
cause proportionally fewer hospital cases than the Delta
coronavirus variant, though public health experts warned the
battle against COVID-19 was far from over.
Similar encouraging evidence about hospitalisation rates
emerged from South Africa on Wednesday, but the head of a
leading African health agency joined the World Health
Organization in cautioning that it was too soon to draw broad
conclusions about Omicron's virulence.
"Let's be careful not to extrapolate what we are seeing in
South Africa across the continent, or across the world," Africa
Centres for Disease Control (CDC) chief John Nkengasong told a
media briefing.
Coronavirus infections have soared wherever highly
infectious Omicron has spread, triggering new restrictions in
many countries.
First identified last month in southern Africa and Hong
Kong, the variant is becoming dominant in much of Europe
including Britain, where daily new infections have soared beyond
100,000.
In Italy, the first Western country to be hit by the
pandemic last year, the National Health Institute said Omicron
would soon predominate, while Greece banned public Christmas
festivities to curb its spread.
But increases in hospitalisations and deaths in South Africa
and Britain since Omicron took hold appear to have been more
gradual, and AstraZeneca https://www.reuters.com/business/healthcare-pharmaceuticals/astrazeneca-shot-third-dose-works-against-omicron-study-2021-12-23
and Novavax https://www.reuters.com/business/healthcare-pharmaceuticals/novavax-says-covid-vaccine-boosts-response-omicron-variant-2021-12-22
joined other vaccine manufacturers in saying their
shots protect against it.
University of Edinburgh https://www.reuters.com/business/healthcare-pharmaceuticals/scotland-reports-fewer-covid-19-hospitalizations-with-omicron-2021-12-22
researchers who tracked 22,205 Omicron patients said on
Wednesday the number who needed to be hospitalised was 68% lower
than they would have expected, based on the rate in patients
with Delta.
Imperial College London https://www.reuters.com/business/healthcare-pharmaceuticals/hospital-stay-risk-omicron-is-40-45-lower-than-delta-uk-study-2021-12-22
researchers reported evidence of a comparable 40%-45% reduction
in hospitalisation risk.
'DON'T OVER-INTERPRET'
Raghib Ali, senior clinical research associate at the
University of Cambridge, said scientists had warned that, with
the surge in UK cases, even a small proportion of
hospitalisations could overwhelm the healthcare system.
However, the UK data was encouraging and "may help justify
the government's decision not to expand restrictions on social
gathering over Christmas in England," he said.
UK hospitalisations supported Wednesday's findings from
South Africa's National Institute for Communicable Diseases
(NICD).
A separate South African government-backed study, yet to be
peer-reviewed, on health workers given the Johnson & Johnson
vaccine identified "clear and early de-coupling" of
hospitalisation from Omicron cases compared with data on Delta.
However, the CDC's Nkengasong said the NICD data, suggesting
Omicron was 70%-80% less severe than Delta, should be
interpreted "with a lot of caution".
"This is early days and public health practice is local," he
said, adding that particular factors such as the young median
age of the South African population could be in play.
On Wednesday, the WHO's technical lead on COVID-19, Maria
van Kerkhove, had said data on Omicron was still too "messy" to
draw firm conclusions.
VACCINE HOPES
On Thursday, AstraZeneca said a three-course dose of its
COVID-19 vaccine offered protection against the variant, citing
data from an Oxford University lab study.
Findings from the study, yet to be published in a
peer-reviewed medical journal, matched those from rivals
Pfizer-BioNTech, and Moderna.
Hours earlier, Novavax Inc said early data showed
its vaccine - authorised for use by the European Union and WHO
but yet to be approved by the United States - also generated an
immune response against Omicron.
As financial markets welcomed the signs that Omicron might
be less severe than feared, global shares extended a rally on
Thursday while safe-haven bonds and currencies eased.
In some countries, meanwhile, the older Delta variant
continued to spread.
The coronavirus death toll in Russia, where officials said
this week they had detected only 41 Omicron cases, passed
600,000 on Thursday, Reuters calculations based on official data
showed, after a surge of Delta-linked infections linked to
Delta.
Only the United States and Brazil have recorded more
coronavirus deaths.
In India, where daily infections hit close to 7,500 on
Thursday with just 236 Omicron cases having been reported,
Prime Minister Narendra Modi was to meet with state chiefs to
discuss ways of containing a possible Omicron surge ahead of the
festive season.
Interactive graphic tracking global spread of coronavirus:
open https://tmsnrt.rs/2FThSv7 in an external browser.
Eikon users can click https://apac1.apps.cp.thomsonreuters.com/cms/?navid=1063154666
for a case tracker.
(Reporting by Reuters bureaux around the world; Writing by John
Stonestreet; Editing by Catherine Evans, Edmund Blair and Mark
Heinrich)