ZURICH: The World Health Organization will decide late this month or in May on emergency use listings for COVID-19 vaccines from Sinopharm and Sinovac following an extended review, a WHO European region official said on Thursday.

"We are in touch with them to review the dossiers that have been submitted by both vaccine manufacturers," WHO-Europe vaccination expert Siddhartha Datta told a virtual press conference. "We will be hearing about a decision on the emergency use listing in April or early May, so please keep an eye on that."

A WHO panel in final stages of review of the Chinese vaccines has said that a decision for at least one could come on April 26, while a second meeting has been planned for May 3, should more time be needed to make a decision on both shots.

Such an emergency WHO listing is a prerequisite for purchase by the COVAX vaccine-sharing facility designed to get shots to poorer countries. It also helps guide countries with less developed regulatory systems about a vaccine's safety and efficacy.

So far, the WHO has issued emergency listings for Pfizer and BioNTech's COVID-19 vaccine, as well as versions of AstraZeneca's vaccine made by the Serum Institute of India and South Korea's AstraZeneca-SKBio.

CanSino's vaccine relies on a viral vector to deliver DNA to prompt an immune response, a technique similar to that used in both AstraZeneca's and Johnson & Johnson's vaccines now being investigated for their association with very rare blood clots combined with low platelet counts.

CanSino has said there have been no reports of blood clots.

Sinovac's vaccine, being used in places including Hong Kong and Brazil, relies on inactivated coronaviruses to generate an immune response, a technique used for decades including against polio.