Photo taken on March 12, 2021 shows AstraZeneca/Oxford vaccines at a hospital in Caceres province in Spain. (Photo:Xinhua)

Chinese vaccine experts said that the inoculation drive in Europe and the global distribution of vaccines will not be greatly affected at the moment, despite concerns over a possible link between AstraZeneca vaccine and blood clots, as more investigation is needed to determine if the rare events resulted from inherent problems with the vaccine.

The European Medicines Agency (EMA) denied that it had already established a causal connection between the Oxford/AstraZeneca vaccine and a rare blood clotting syndrome, after Marco Cavaleri, the EMA's head of vaccines, told the media there was a link, the Guardian reported on Tuesday.

The agency said in a statement that it expected to announce its findings on Wednesday or Thursday.

The World Health Organization (WHO) also released a statement on Tuesday saying that the "risk-benefit" balance for AstraZeneca's COVID-19 vaccine was still "largely" positive.

Despite the EMA's denial, a trial of the vaccine on children was halted, media reported on Wednesday.

The AstraZeneca COVID-19 vaccine was given WHO Emergency Use Listing in February, and on February 25, UNICEF signed a COVID-19 vaccine supply agreement with AstraZeneca that enabled access to 170 million doses secured under the COVAX agreement for about 85 countries and regions.

More evidence is needed to determine whether the reported embolic and thrombotic events were caused by inherent problems with the vaccine or by the quality of production, Feng Duojia, president of the China Vaccine Industry Association, told the Global Times on Wednesday.

Tao Lina, a Shanghai-based vaccine expert, told the Global Times that the possibility of the vaccine causing blood clots cannot be ruled out - but if the occurrence rate is one in 100,000 or one in 1 million, then it should not be a cause for concern.

Both experts said that the vaccination process in Europe and the global distribution of vaccines will not be much affected at the moment.

Feng said the global vaccine roll-out might see a big change after the WHO makes a clear determination about the vaccine, but for now the benefits still outweigh the risk of blood clots.

According to WHO website , 272 candidate vaccines are being developed worldwide, with 86 in clinical trials in countries and regions including Germany, China, Russia, Britain, and the US.

Some Chinese experts previously suggested that the WHO should suspend the distribution of the AstraZeneca vaccine, after some 15 European countries halted its use over blood clot concerns in the middle of March.