A growing number of countries are fully or partially suspending the AstraZeneca COVID-19 vaccine, as the World Health Organization (WHO) is reviewing the available vaccine data. 

"This does not necessarily mean these events are linked to COVID-19 vaccination, but it's routine practice to investigate them, and it shows that the surveillance system works and that effective controls are in place," WHO Director-General Tedros Adhanom Ghebreyesus said on Tuesday.

The WHO's Global Advisory Committee on Vaccine Safety is reviewing the available data and is scheduled to meet on Tuesday for further discussion. 

Tedros said the WHO was aware multiple countries had suspended the use of AstraZeneca's COVID-19 vaccine following reports of blood clots in people who had received the vaccine from two batches produced in Europe. 

France, Spain, Germany and Italy on Monday announced their suspension of the vaccine.  

French President Emmanuel Macron suspended use of the vaccine in the country as a precaution for at least 24 hours. The halt overshadowed the first day of French pharmacies carrying out COVID-19 vaccinations.  

Spain announced a minimum 15-day suspension effective immediately, while Germany said it would stop administering the AstraZeneca vaccine on the same day. 

Italy's suspension expanded nationwide as a precautionary measure, after its northern region announced a halt in use following the death of a local teacher on Sunday who was inoculated one day before. 

As of Tuesday, countries who announced the suspension of the vaccine are piling up. Besides France, Germany, Spain and Italy, European countries including the Netherlands, Ireland, Cyprus, Denmark, Austria, Iceland, Bulgaria, Luxembourg, Estonia, Lithuania and Latvia have already suspended the vaccine. 

Thailand on Friday became the first Asian country to halt the use of the jab over safety concerns. 

AstraZeneca said on Sunday a review of safety data of people vaccinated with its COVID-19 vaccine has shown no evidence of an increased risk of blood clots. 

"An analysis of our safety data of more than 10 million records has shown no evidence of an increased risk of pulmonary embolism or deep vein thrombosis in any defined age group, gender, batch or in any particular country with COVID-19 vaccine AstraZeneca," a spokesperson for AstraZeneca said. 

"In fact, the observed number of these types of events is significantly lower in those vaccinated than what would be expected among the general population." 

Late last week, the European Medicines Agency stressed that there was no indication the shot was causing blood clots, adding that it believes the vaccine's benefits "continue to outweigh its risks." The WHO also said, "There is no indication to not use it."

(With input from agencies)