AstraZeneca's (AZN.L) share price came under pressure on Tuesday as the company's COVID-19 vaccine faced renewed scrutiny over possible links to instances of rare blood clots.
In recent days the Netherlands has stopped its rollout of the drug company's COVID-19 vaccine, UK medical authorities have confirmed they are considered new restrictions on the vaccine, and a top European medical official said it was "increasingly difficult" to deny links between the jab and rare forms of blood clots.
The Netherlands became the latest country to pause rollout of the AstraZeneca jab over the weekend amid concerns about possible blood clotting complications.
The UK's Channel 4 News reported on Monday evening that UK medical regulators were also looking at the safety of the vaccine. The report claimed regulators were considering blocking the vaccine for under-30s, amid concerns that the jab could put young women at risk of a rare form of blood clots.
Britain's Medicines and Healthcare products Regulatory Agency (MHRA) confirmed in a statement it was investigating "very rare and specific type
s of blood clots" but emphasised that people should continue to get their jabs.
WATCH: UK regulator says AstraZeneca vaccine safe despite blood clot fears
"People should continue to get their vaccine when invited to do so," Dr June Raine, chief executive of the MHRA, said in a statement supplied to Yahoo Finance UK.
“Our thorough and detailed review is ongoing into reports of very rare and specific type
s of blood clots with low platelets following the COVID-19 Vaccine AstraZeneca. No decision has yet been made on any regulatory action.”
Vaccines minister Nadhim Zahawi told BBC Breakfast the regulator was looking "very closely" at the issue but said blood clots appeared to be "very rare" and it was "important" for people to continue to get their vaccines.
New safety monitoring data was published by the MHRA last week showing 30 cases of blood clots had been reported in relation to the 18.1 million doses of the AstraZeneca vaccine so far administered.
AstraZeneca has been contacted for comment.
Shares in AstraZeneca were down 0.4% on Tuesday, the first day of trading in London since last Thursday. The broader FTSE 100 (^FTSE) was up 1.4% on the day.
AstraZeneca's COVID-19 vaccine has faced repeated scrutiny over possible links to blood clots. Multiple European countries suspended administering the vaccines last month amid concerns it could cause rare clotting events. The European Medicines Agency (EMA) ultimately concluded the vaccine was “safe and effective”.
On Monday, a top official from the EMA said it was "increasingly difficult" to deny a link between the vaccine and blood clots. Marco Cavaleri, head of vaccine strategy at the EMA, told the Italian newspaper Il Messaggero it was "clear there is an association" but said the medical regulator was still assessing what was behind the correlation.
Cavaleri said the benefits of the vaccine still outweighed the risks. He said the EMA was assessing in granular detail how the vaccine affected different groups with a particular focus on young women, according to a translated summary from Sky News.
The EMA was subsequently forced to deny it had concluded there was a causal link between the vaccine and blood clotting events. The EMA said it was reviewing the issue and expected to report its findings later this week.
Stella Kyriakides, the European Commissioner for Health and Food Safety, said the results of the EMA’s review were expected on Wednesday. Kyriakides said on Twitter she was in "close contact" with the agency.