Oxford/AstraZeneca is the most widely given vaccine, administered in 170 of the 215 countries where campaigns have begun.
It is followed by Pfizer/BioNTech, which is being used in at least 97 countries; Moderna (at least 46); Sinopharm (45); Sputnik V (40); Johnson & Johnson (29).
The joint announcement by AstraZeneca and Siam Bioscience, a firm owned by Thailand's king, comes amid public anxiety about vaccine supplies, as the country suffers its most severe outbreak so far.
It did not say whether the Thai plant would make all 6 million doses that Thailand's government has promised would be available this month.
In a statement, Gou said that his Yonglin Foundation plans to apply for 5 million BioNTech doses made and packaged in Germany to be imported into Taiwan.
The shots would be airlifted from Germany to Taiwan without going via any middleman, he added.
"The situation was different with the AstraZeneca vaccine, which induced particularly low levels of antibodies neutralising" the Indian variant, the study said.
Macron and South Africa President Cyril Ramaphosa will hold talks and then head to the University of Pretoria to launch a programme to support African vaccine production, a project backed by the European Union, United States and World Bank.
The deadline for the contract is set for mid-June, according to the Commission, and the EU says the company should face financial penalties if it does not meet this deadline.
AstraZeneca's French-Australian boss Pascal Soriot has argued that his company's contract with the EU binds it only to a "best reasonable efforts" clause.
The Competition and Markets Authority said it was inviting comments from any interested party on the deal to help with its assessment. It has set a deadline of June 3 for the insight from any stakeholders.
Two mass vaccination centres operated by the military in Tokyo and Osaka will open next week and are expected to administer the two-shot Moderna vaccine, initially to the elderly.
The southern African country has so far received three batches of the AstraZeneca vaccine -- 300,000 doses under the Covax vaccine sharing facility, 50,000 from India and 102,000 from the African Union.
An upcoming study by Oxford University showed that a third dose of the vaccine boosted antibodies to the coronavirus spike protein among participants, it added.
Earlier, Alberta -- with the highest per capita number of Covid cases of any Canadian province or US state -- altered its immunization strategy, saying it wasn't sure when it would receive additional shipments of the AstraZeneca vaccine.