AstraZeneca said on Monday that its COVID-19 vaccine is 79% effective at preventing the disease and does not increase the risk of blood clots following its phase III efficiency trial in the United States, reported AFP.

According to the firm, the shot was also 80% effective for people over the age of 65. Several countries had advised against administering the jab to older people due to a lack of data among elderly participants in previous trials. The jab doesn’t increase the risk of blood clots, the pharmaceutical firm said.

Also read: Denmark reports one death after AstraZeneca jab

The vaccine is 100% effective at preventing severe disease and hospitalisation, AstraZeneca said.

In the phase III trials conducted in the US, 32,449 participants were involved, two-thirds of whom received the jab. 20% of the participants were of age 60 or more and 60% had a pre-existing health condition, such as diabetes, severe obesity or cardiac disease, which increase the risk of severe COVID-19, the company said in a statement.

Also read: German leader Angela Merkel says ‘would take AstraZeneca vaccine’

The trial’s independent data safety monitoring board found no increased risk of thrombosis among the 21,583 participants who received at least one dose of the vaccine, the statement read. Thrombosis is the process of the formation of blood clots in blood vessels.

Some leading EU countries have resumed AstraZeneca vaccinations after the European Medicines Agency said Thursday the jab was “safe and effective” and was not linked to an increased risk of blood clots.

Also read: Europeans lose trust in AstraZeneca COVID vaccine amid safety concerns

AstraZeneca said it was preparing to submit its findings to the US Food and Drug Administration to authorise the shot for emergency use.