UPDATE 2-Coronavirus vaccine hopes guide British stocks higher

* FTSE 100 up 0.6%, FTSE 250 up 0.4%

* Reports of coronavirus treatment trigger sharp gains

* Imperial Brands, GSK underperform FTSE 100

* Smurfit Kappa rises, supports peer DS Smith
(Adds news items, analyst comments, updates to closing prices)

By Muvija M and Shashwat Awasthi

Feb 5 (Reuters) - UK shares got a shot in the arm on
Wednesday after media reports that scientists had developed a
drug against the China-linked coronavirus, though Imperial
Brands and GlaxoSmithKline missed out after downbeat financial
updates.

The FTSE 100 overturned earlier losses to rise 0.6%
and the FTSE 250 added 0.4%. Both indexes ended higher
for the third straight session.

A Chinese TV report said researchers at Zhejiang University
had found an effective drug for the virus, while Britain's Sky
News said researchers had made a "significant breakthrough" in
developing a vaccine.

Though the World Health Organisation played down the
reports, markets bet that the outbreak would be contained soon.
An index of travel and leisure stocks jumped 1.3%
and enjoyed its best day in more than a week.

"Traders have latched onto the headlines and are buying into
the market with the view the health crisis could be brought
under control," CMC Markets analyst David Madden said.

The blue-chip bourse had dropped 3.4% in January, more than
twice the fall suffered by its European counterpart due
to its greater exposure to commodity prices.

However, the UK benchmarks have rebounded this week after
China announced stimulus measures to safeguard against any hit
from the outbreak, which has killed nearly 500 people.

Tobacco group Imperial Brands slid 6.6%, its worst day in
more than four months, after it forecast lower profit because of
a U.S. regulatory ban on some flavours of cartridge-based vapour
devices.

After noon, GSK skidded 4.2% on its worst day since
early October, as cheap competition to its respiratory medicines
led to fourth-quarter earnings missing analysts' estimates.

"The launch of generic rivals to blockbuster asthma
treatment Advair/Seretide was always going to cause GSK problems
this year," Hargreaves Lansdown analyst Nicholas Hyett said.

By contrast, packaging products makers Smurfit Kappa
and DS Smith topped the main board, rising more than 6%
each, after the former posted higher annual core earnings.

Housebuilder Barratt climbed 2.2% higher after
announcing an increase in first-half earnings and a special
dividend.

Among midcaps, Tullow Oil firmed 4.6% after a source
said the energy firm plans to cut a third of its staff to save
about $20 million. Its shares have tanked nearly 75% since
November amid a plethora of setbacks.
(Reporting by Muvija M in Bengaluru; Editing by Bernard Orr)