Preliminary results from the late-stage human trial of Russia's main coronavirus vaccine candidate could include data from 5,000-10,000 participants, Denis Logunov, a director at the Gamaleya Institute that developed the vaccine, said on Monday.

Russia's plan to publish preliminary data about the Sputnik V jab as early as November is likely to make it one of the first vaccine developers to share any data from a final stage trial, known as Phase III, but also puts it at odds with competitors.

The Sputnik V trial, involving 40,000 volunteers, has been underway in Moscow since the beginning of September.

Interim results, when published, will be based on the first 42 days of monitoring participants, Gamaleya developers told Reuters last month.

To meet a November target, the interim results will have to be based on a limited data set - between 5,000 and 10,000 people - due to logistical challenges.

Two dozen clinics in Moscow have been racing to administer the vaccine to volunteers, but only around 16,000 people have received the first dose of the two-shot jab so far. There is then a 21-day wait until the second dose can be administered.

Setting a target timeframe for publishing interim results is unusual.

Many Western vaccine developers have said the publication of interim results depends on how many volunteers report becoming infected with coronavirus, thereby allowing the placebo and vaccine groups to be compared. A date for when this threshold is met cannot be set in advance.

Russia has been pushing ahead with its potential coronavirus vaccine at full speed, licensing it for domestic use before large-scale trials had even begun. It is also marketing the shot abroad.

Interim Phase III results may be useful for foreign regulators deciding whether to procure supplies of Sputnik V or authorise local trials of the jab.

Russia will send Indian regulators weekly data updates from its trial, a source told Reuters on Saturday, after plans to hold Phase III trials in India were briefly put on ice.

Indian regulators knocked back plans to hold large-scale trials of the Sputnik V vaccine saying the scale of initial, Phase I and II trials conducted in Russia earlier this year was too small. An agreement was reached for an adaptive Phase II and III trial to be held in India instead.

At least 300 million doses of Sputnik V are expected to be manufactured in India. It will also be produced in Brazil, South Korea and China, Russia's sovereign wealth fund, responsible for marketing the vaccine globally, said on Monday.