Russia’s first big international shipment of its coronavirus vaccine — 300,000 doses sent to Argentina last week — consisted only of the first dose of the two-shot vaccine, which is easier to make than the second dose, sources told Reuters.
Unlike most other Covid-19 vaccines, which are given as two shots of the same product, the Russian Sputnik V vaccine relies on two doses delivered using different inactive viruses, known as vectors.
The Gamaleya Institute that developed the vaccine says it is more than 91 per cent effective after the two-dose course.
But some Russian manufacturers are finding the second dose, which is administered 21 days after the first, to be less stable, two sources said, revealing a new challenge for the country’s ambitious national inoculation programme.
The decision to send doses of the vaccine to Argentina caused an outcry at home, where the lifesaving drug is still mostly unavailable to the general public outside the capital Moscow.
Russia has not said exactly how many people have received it. The Gamaleya Institute said last week 650,000 doses had been released for Russia’s domestic vaccination programme so far.