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  • (upbeat music)

  • - [Narrator] Chinese COVID-19 vaccines are being used

  • in dozens of countries.

  • - China has donated vaccines everywhere

  • for those countries who need help.

  • - [Narrator] But these shots have some

  • of the lowest efficacy rates

  • among globally used coronavirus vaccines,

  • ranging between 50 to nearly 80%.

  • Compare this with shots from Pfizer-BioNTech, Moderna

  • and Russia's Sputnik V.

  • The head of China CDC in early April said the efficacy

  • of some vaccines was not high.

  • And this also included ones from his own country.

  • So China is looking to bolster the protection rate

  • and one way is to mix and match different types of vaccines.

  • And this idea isn't new.

  • - We really welcome studies

  • that would look at mix and match regimens.

  • - [Narrator] Spain is also interested in combining vaccines

  • while researchers in the UK

  • and Russia are already studying this.

  • So as China joins the ranks

  • of countries looking to mix and match,

  • here's how it can be a key

  • to overcoming multiple vaccination challenges at once.

  • Most Chinese vaccines and other shots currently in use

  • require two doses, creating an opportunity to mix and match.

  • Some immunologists believe this could have a number

  • of benefits like boosting the immune response.

  • - The theory is that if you train the immune system

  • to recognize a virus in a slightly different way each time,

  • then you might get a broader

  • and more durable immune response.

  • - [Narrator] And a more robust immune response

  • is important since China has confirmed cases

  • of new and more transmissible variants

  • that were first identified in the UK and South Africa.

  • Mixing and matching for this reason has gotten support

  • from at least one Chinese drug maker so far.

  • Some immunologists also say

  • that mixing and matching could ease the pressure

  • from the vaccine supply chain.

  • So for example,

  • in countries that are rolling out Chinese vaccines

  • along with other supplies,

  • using two different shots could give doctors more options

  • when patients come in for the second dose.

  • But one of the most important reasons

  • is when there are severe side effects

  • from one of the vaccines.

  • - If someone perhaps has a strange

  • or severe allergic reaction to the first shot that they get,

  • perhaps then you could avoid that

  • by giving them the second dose from a different vaccine.

  • - [Narrator] The idea became particularly important

  • after regulators started investigating

  • rare blood clotting disorders linked

  • to AstraZeneca's COVID vaccine.

  • As of late March, 79 people in the UK

  • have had severe blood clots

  • out of the 20 million administered doses

  • of AstraZeneca's vaccine.

  • In France and Germany,

  • health authorities are advising younger people

  • who have received a first dose of AstraZeneca

  • to get a second dose of a different vaccine.

  • The drug maker said it's working with health regulators

  • and starting the rare blood clotting events

  • and possible causes.

  • While these upsides could bring China and other countries

  • closer to getting their population vaccinated,

  • health authority say there's still a lot to learn

  • about possible side effects or how it may affect efficacy

  • of the vaccines, especially when it comes

  • to combining shots made with different technologies.

  • - The vaccine, such as Chinese vaccine

  • and the vaccines by AstraZeneca and Johnson & Johnson

  • are vaccines that use a virus as the vector

  • to get the genetic instructions into your body.

  • - [Narrator] Whereas Pfizer-BioNTech and Moderna vaccines

  • use a new gene-base technology involving messenger RNA,

  • where molecules carry genetic instructions.

  • - So we're not too sure what happens

  • when you mix these two technologies together.

  • - [Narrator] Chinese health authorities have said people

  • can receive different brands that use the same technology,

  • but don't recommend mixing vaccines

  • with different technology so far.

  • But now trials with the combination

  • of two homegrown vaccines with different technologies

  • are underway in China with more than a hundred volunteers.

  • The country is also working on its own mRNA vaccine

  • and looking closely at approving Pfizer-BioNTech shot,

  • according to people familiar with the matter.

  • This would pave the way for China to mix and match

  • its more conventional vaccines with mRNA shots.

  • Similar to how researchers in the UK are studying

  • the combination of AstraZeneca

  • with Pfizer-BioNTech or Moderna.

  • Those results are expected as early as may

  • - Immunologists, when you speak to them

  • about this sort of process, are pretty enthusiastic about it

  • and optimistic that it's going to work.

  • But that's maybe the one big drawback

  • is we want to make sure that it works,

  • we want to make sure that it isn't worse,

  • you don't get a worse immune response

  • than if you had two doses of the same vaccine.

  • (gentle music)

(upbeat music)

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Why China Is Considering Mixing Covid-19 Vaccines | WSJ

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    joey joey posted on 2021/05/30
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