Enlarge / MOSCOW, RUSSIA - SEPTEMBER 4, 2020: Medical staff with newly delivered boxes containing COVID-19 vaccine in a cold room at No2 Outpatient Clinic in southern Moscow. (credit: Stanislav Krasilnikov / Getty Images )

Russia has been one of the countries hit hard by the COVID-19 pandemic. But its response to that has been a bit... unusual. As many other countries have, Russia worked to develop its own vaccine. But while that development was still in progress, it announced that it wasn't going to wait for detailed safety data , and instead roll the vaccine out to millions. Shortly afterwards, it became clear that the country was actually going to run a standard phase 3 clinical trial , albeit a large one, involving 40,000 people.

It was hard to judge whether any of this was reasonable, because few details of the vaccine itself were available. But that changed somewhat on Friday, as the people who developed the vaccine published the results of the initial clinical trials. And so far, it seems to be about as effective as some of the other ones that have been made it past initial trials.

Two viruses better than one?

As our earlier coverage mentioned, the vaccine is composed of two different engineered viruses. These contain the backbone of an innocuous virus, called an adenovirus, engineered to include the gene that encodes the major surface protein from the SARS-CoV-2 virus. This protein, called Spike, is what the coronavirus uses to latch on to and enter cells. The use of adenovirus allows the immune system to learn to recognize the Spike protein while the body only experiences a harmless adenovirus infection.