UPDATE 2-EU advises against second AstraZeneca shot for people with blood clots

* Says second dose must not be given to anyone with
thrombosis

* Suggests three-week window for monitoring signs of clots

* Reiterates that clots after vaccine are 'very rare'
(Adds detail, no immediate comment from company)

By Pushkala Aripaka

May 21 (Reuters) - The second shot of the COVID-19 vaccine
developed by AstraZeneca and the University of Oxford
must not be given to anyone who has had blood clots with low
blood platelets after receiving the first, Europe's medicines
regulator said on Friday.

The advice for healthcare professionals was provided by the
European Medicines Agency (EMA) as part of an ongoing review
into rare, but severe blood clots possibly linked to inoculation
after the shot and also to Johnson & Johnson's
coronavirus vaccine.

The EMA has been looking into such clots in the abdomen and
brain since March and has recommended that both vaccine labels
carry a warning on the clotting issues while maintaining that
the overall benefits outweighed any risks.

Both the AstraZeneca and J&J vaccine use different versions
of a cold virus to deliver instructions for making coronavirus
proteins into cells to produce an immune response.

"While blood clots with low blood platelets following
vaccination are very rare, EMA continues to advise people to be
aware of symptoms ... so they can receive prompt specialised
medical treatment if needed," the EMA said https://www.ema.europa.eu/en/news/vaxzevria-further-advice-blood-clots-low-blood-platelets
on Friday.

The watchdog said people should be on guard for any signs of
any blood clots or low platelets within three weeks of receiving
the first shot of AstraZeneca's vaccine, Vaxzevria, and that the
latest recommendations will be added to the vaccine's product
information.

AstraZeneca and the University of Oxford had no immediate
comment.

The new guidance adds to the problems that have dogged the
AstraZeneca vaccine, including supply cuts, production snags and
legal action from the European Union for under-delivering on
promised doses.

At the same time, evidence is mounting that it is effective.
On Thursday, a British study suggested that two doses of the
AstraZeneca-Oxford vaccine may be around 85% to 90% effective
against symptomatic COVID-19.

A media report this week also said a study found that a
third booster dose of the vaccine could increase antibodies in
people.
(Reporting by Pushkala Aripaka in Bengaluru; Editing by
Ramakrishnan M. And Barbara Lewis)