Double-jabbed are half as likely to be infected with Covid-19, study suggests People who have received both doses are also more likely to have a milder infection. React found vaccine effectiveness was 49% among people who reported that they had been double-jabbed (Image: PA Images) Get the latest news from across Lancashire - don't miss our email bulletinsInvalid EmailSomething went wrong, please try again later. Subscribe for free We use your sign-up to provide content in ways you've consented to and to improve our understanding of you. This may include adverts from us and 3rd parties based on our understanding. You can unsubscribe at any time.More info