Russia’s coronavirus vaccine appears to be safe and induces immunity, early trials have found.

The controversial remedy, called Sputnik V, was unveiled by the Kremlin in August without proper testing at the time.

Results published in medical journal The Lancet on Friday suggest the vaccine causes no major adverse effects despite serious international concern over its safety.

Participants in two small rounds of early testing induced antibodies, suggesting it develops immunity in survivors.

“The two 42-day trials – including 38 healthy adults each – did not find any serious adverse effects among participants, and confirmed that the vaccine candidates elicit an antibody response,” The Lancet said.

The Kremlin approved Sputnik V on August 11, making it the world’s first Covid-19 vaccine cleared for use.

The vaccine appears to have been safe for a small group of test participants

Experts around the world dubbed Russia’s announcement as “unethical” and “reckless” as the vaccine had not been tested on a large scale.

But Pahse 3 testing of the vaccine, developed by Moscow’s Gamaleya Research Institute, began this week and will end with 40,000 participants.

Two small trials have already been carried out and suggest that there are no major safety concerns over the medicine.

76 volunteers were injected with a frozen formulation of the vaccine planned for large scale use.

No adverse effects were detected over the 42 day trial.

And Sputnik has been reported as triggering a T cell response, providing long-term protection against reinfection.

The early results suggest the vaccine is safe

Scientists have debated whether Covid-19 survivors can catch the disease more than once after several cases emerged from around the globe.

The trials took place in two hospitals in Russia.

Volunteers were adults between 18 and 60 who self-isolated after they registered and remained in hospital for 28 days after the vaccination.

The trials took place in two Russian hospitals and returned promising results

Dr Ohid Yaqub, senior lecturer at the University of Sussex’s Science Policy Research Unit, told the Independent: “Normally, such a study would be the basis for debating whether to proceed into larger trials and the costs that entails.

“In that context, the study results are encouraging in terms of safety and possible efficacy.

“However, in the context of regulatory approval, the design and size of a phase 1/2 study is not anywhere near sufficient for widely recognised standards of approval. The study was not randomised, and it was not large enough to detect rarer safety issues.”

Kirill Dmitriev, the head of the Russian Direct Investment Fund (RDIF), Russia’s sovereign wealth fund, which has backed the vaccine, told Reuters: “With this (publication) we answer all of the questions of the West that were diligently asked over the past three weeks, frankly with the clear goal of tarnishing the Russian vaccine.

“All of the boxes are checked, now... we will start asking questions of some of the Western vaccines.”