Stronger immune response, longer-lasting protection among benefits, authorities believe RIYADH: Saudi Arabia on Tuesday reiterated that mixing any of the coronavirus vaccines approved in the Kingdom is both safe and effective. The health ministry said that mixing vaccine options — getting a first shot from one brand and a second from another — gives a stronger immune response and longer-lasting protection from the virus. Vaccines approved in the Kingdom include Oxford-AstraZeneca, Pfizer-BioNTech, Johnson & Johnson, Moderna, Sinovac and Sinopharm. Ads by optAd360 A UK study released in the summer showed mixing some vaccines worked well for priming the immune system against the virus. The Oxford University study compared those who took two shots of Pfizer-BioNTech, those with two shots of AstraZeneca and those given a mix of both. A number of countries, including the UK, Germany and Canada, already allow vaccines to be mixed. In June, the Saudi public health authority authorized the mixing of vaccine types and said the technique likely provided a better immune reaction. Saudi Arabia has administered over 38 million doses of the various vaccines so far. The health ministry reported another 138 cases of the virus in the past 24 hours, with six more deaths. There are currently 2,463 active cases of which 636 are critical. Since the start of the pandemic 8,591 people have died of COVID-19 in the Kingdom.