The situation will be assessed during the coming week, and vaccinations with the AstraZeneca vaccine can continue at the earliest on March 29.

Taneli Puumalainen, the chief physician at the Finnish Institute for Health and Welfare, speaking at a press conference about suspending the use of AstraZeneca coronavirus vaccine at the Government Palace on March 19, 2021. Photograph: Fanni Uusitalo/The Finnish Government

The Finnish Institute for Health and Welfare (THL) suspends the use of the AstraZeneca Covid-19 vaccine because of two cases of cerebral venous sinus thrombosis (clots in the vessels draining blood from the brain) within 4–10 days of receiving the AstraZeneca Covid-19 vaccine.

“If you have already received the AstraZeneca Covid-19 vaccine,” THL noted in a statement on Friday, “be alert for serious reactions that may occur three days after vaccination or later.”

Both patients had medical risk factors for blood clots, and, according to THL, “the analysis of the cases is still incomplete.”

 As a precautionary measure, the Finnish Institute for Health and Welfare (THL) has decided to suspend the use of the AstraZeneca vaccine in Finland until more information on the cases is available and possible causality can be determined. The suspension is effective immediately.

The situation will be assessed during the coming week, and vaccinations with the AstraZeneca vaccine can continue at the earliest on March 29. THL will report on its findings without delay. Vaccinations with other vaccines will continue normally.

The National Advisory Committee on Vaccines (KRAR), appointed by THL, is in favor of limiting the use of the AstraZeneca vaccine as the analysis of the cases is incomplete.

In its report released on March 18, the European Medicines Agency (EMA) assesses that the benefits of the AstraZeneca Covid-19 vaccine continue to outweigh the risks of side effects. The vaccine prevents hospitalization and death from Covid-19.

EMA is further analyzing whether the vaccine is associated with very rare blood coagulation disorders involving low levels of blood platelets and an increased risk of blood clots. The two cases recently reported in Finland may be connected to such coagulation disorders. The matter is currently being investigated.