GENEVA, Switzerland (AFP) — The World Health Organization’s vaccine safety experts gave renewed backing to AstraZeneca’s COVID-19 jab on Friday, having reviewed reports of blood clotting after immunisation.

The WHO Global Advisory Committee on Vaccine Safety said the AstraZeneca jab “continues to have a positive benefit-risk profile, with tremendous potential to prevent infections and reduce deaths across the world.”

“The available data do not suggest any overall increase in clotting conditions such as deep venous thrombosis or pulmonary embolism following administration of COVID-19 vaccines,” the committee said in a statement.

The statement followed the European Medicines Agency (EMA) giving their green light to the vaccine on Thursday.

The WHO committee said reported rates of so-called thromboembolic events after COVID-19 vaccines were in line with the expected number of diagnoses of these conditions.

Deep venous thrombosis and pulmonary embolisms “occur naturally and are not uncommon”, and also occur as a result of COVID-19, the experts said.

“The observed rates have been fewer than expected for such events,” they concluded.

“While very rare and unique thromboembolic events in combination with thrombocytopenia, such as cerebral venous sinus thrombosis (CVST), have also been reported following vaccination with the AstraZeneca COVID-19 vaccine in Europe, it is not certain that they have been caused by vaccination.”

European regulators have reviewed 18 such cases out of more than 20 million AstraZeneca COVID-19 vaccinations in Europe, and “a causal relationship between these rare events has not been established at this time”.

Several European countries resumed AstraZeneca vaccinations Friday after the all-clear from the EU’s EMA authority.

Worries that AstraZeneca’s COVID-19 vaccine may cause blood clots have seen countries from Venezuela to Indonesia pause its use in recent days.

Germany and Italy said they were using the jab again as of Friday after the EMA said it was “safe and effective”.

Other European countries including the Netherlands, Spain and Portugal are also ending their suspension.

The WHO vaccine safety experts recommended that countries continue monitoring COVID-19 vaccine safety, and report suspected adverse events.

They also agreed with the EMA’s plans to further investigate and monitor for such events.

The committee said health care professionals and people being vaccinated should be given instruction on recognising the signs and symptoms of all serious adverse events after immunisation with COVID-19 jabs.