Factbox: Countries weigh COVID-19 vaccines ‘mix and match’


A medical officer administers a dose of the Pfizer-BioNTech COVID-19 “Comirnaty” vaccine at a vaccination center in Paris as part of the coronavirus disease (COVID-19) vaccination campaign in France, May 12, 2021. REUTERS / Gonzalo Fuentes

A growing number of countries are considering switching to different COVID-19 vaccines for second doses due to supply delays and safety concerns that have slowed their vaccination campaigns. Read more

Several medical studies to test the effectiveness of the COVID-19 vaccine switch are underway. Read more

Here are the countries that are considering or have decided to adopt such a solution:


* Officials said in May that people who received the COVID-19 vaccine from AstraZeneca (AZN.L) could be offered a second dose of another vaccine, a decision based on concerns about supply as well as on the increased incidence of rare blood clots related to first doses produced by the Anglo-Swedish pharmacist. Read more


* In April, Chinese researchers were testing the COVID-19 vaccine dose mix developed by CanSino Biologics (6185.HK) and a unit of Chongqing Zhifei Biological Products (300122.SZ), according to clinical trial registration data.

* China’s top disease control official said on April 12 that the country “is formally considering” mixing COVID-19 vaccine doses developed with different technologies to increase their effectiveness.


* The Finnish Institute of Health and Welfare said on April 14 that recipients of a first dose of the AstraZeneca vaccine under the age of 65 could receive a different injection for their second dose, as authorities warned. guard against delays in the deployment of the country. Read more


* The Haute Autorite de la Santé (HAS), the highest health consultation authority in France, recommended in April that people under the age of 55 receiving a first injection of the AstraZeneca vaccine receive a second dose with a vaccine told messenger RNA, although the dose mix didn’t. still been evaluated in trials. Read more


* Norway said on April 23 that it would offer those who received a dose of the AstraZeneca vaccine an injection with an mRNA vaccine as the second dose.


* South Korea announced on May 20 that it will hold a mixed trial of COVID-19 vaccines, mixing doses of AstraZeneca with those developed by Pfizer and other drugmakers. Read more


* Spain’s Health Minister Carolina Darias said on May 19 that the country would allow people under the age of 60, who received a first dose of the AstraZeneca vaccine, to receive a second dose of the AstraZeneca vaccine or the Pfizer vaccine (PFE.N). Read more

* A COVID-19 vaccine mix study, conducted by the Spanish state-backed Carlos III Health Institute, found that administering a dose of the Pfizer vaccine to people who have already received a first injection of AstraZeneca vaccine is safe and highly effective, preliminary results showed on May 18 more


* The Swedish health agency said on April 20 that people under 65, who received an injection of the AstraZeneca vaccine, would receive a different vaccine for their second dose.


* Britain said in January it would allow people to receive a different vaccine for a second dose on extremely rare occasions, such as if the first vaccine was out of stock. Read more

* The first results of a study led by the University of Oxford published on May 12 found that people who received the Pfizer vaccine followed by a dose of AstraZeneca, or vice versa, were more likely to report symptoms mild or moderate current immunizations than if they received two of the same type. https://bit.ly/3fraZz9

* Novavax (NVAX.O) said on May 21 that it would participate in a mixed COVID-19 vaccine trial to test the use of an additional vaccine dose from a different producer as a booster. The trial will start in June in the UK


* In January, CNBC reported that the US Centers for Disease Control and Prevention (CDC) had updated its guidelines, allowing a mix of shots from Pfizer / BioNTech (22UAy.DE) and Moderna (MRNA.O) ) with an interval of at least 28 days. between the two inoculations, and only for “exceptional situations”.

Our standards: Thomson Reuters Trust Principles.


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