Surging coronavirus cases and deaths in Russia show the Delta variant's havoc on a largely unvaccinated population

• Russia's daily coronavirus cases have more than doubled in the last month.
• Deaths are climbing, too, as the Delta variant becomes more widespread.
• It's a lesson in what happens when Delta strikes a mostly unvaccinated country, experts said.

Nearly a year after becoming the first nation to authorize a coronavirus shot, Russia has fallen behind in the global vaccine rollout. Just 15% of its population has received at least one dose.

So when Russia identified its first cases of the Delta variant in May, the threat loomed larger than in highly vaccinated countries like Israel, the US, or the UK.

In the last month, Russia's daily coronavirus cases have more than doubled, from around 8,600 to around 19,500. Deaths have ticked up 54% during the same time, from around 375 per day to 575, according to Our World in Data, a research project from the University of Oxford. (It's possible that these tallies are undercounts, given past discrepancies between Russia's official COVID-19 death toll and its sharp increase in mortality during the pandemic.)

At the same time, Delta has come to represent around 88% of Russia's coronavirus cases, according to GISAID, a global database that collects coronavirus genomes.

"Probably lax use of personal protective measures - like mask use, social distancing, avoiding indoor gatherings, and so forth - is part of the problem, but the Delta variant is really the core part of it," Davidson Hamer, a professor at the Boston University School of Public Health, told Insider.

Delta is the most transmissible coronavirus variant to date, and may be deadlier than its predecessors. An analysis from Public Health England found that Delta was associated with a 60% increased risk of household transmission compared with the Alpha variant discovered in the UK, though more recent estimates suggest the difference is closer to 40%. The Alpha variant is already about 50% more transmissible than the original strain, according to the Centers for Disease Control and Prevention.

Researchers in Scotland also found that getting infected with the Delta variant doubled the risk of hospital admission relative to Alpha, though vaccines lower that risk. (Previous studies have suggested that the Alpha variant may be 30 to 70% deadlier than the original strain.)

Experts say Delta's spread makes it all more imperative for countries to get residents vaccinated as quickly as possible. Dozens of other nations, including New Zealand, Pakistan, and Venezuela, still have vaccination rates below 15%.

"Given the increased impact of the Delta variant, it's likely that around 85% of a population will need to be vaccinated into order to cross the herd immunity threshold," Michael Head, a senior research fellow at the University of Southampton, told Insider. "That's going to be difficult to achieve in many settings."

Russia is struggling with vaccine skepticism

The Russian government reported vaccine shortages in some areas of the country on Friday, but for the most part it doesn't suffer from a lack of supply. The country has four domestically made vaccines, the most widely available of which, Sputnik V, has been distributed to the public since December.

But Russia is contending with vaccine hesitancy.

Its approval process for Sputnik V raised red flags last summer when Russia's health agency cleared the vaccine for distribution before it had completed late-stage clinical trials - and after just 38 people had received the shot. By February, an interim analysis published in The Lancet found that Sputnik V was around 92% effective at preventing symptomatic COVID-19. Sputnik V developers said Tuesday that the shot is also around 90% effective against the Delta variant - but Hamer said to take that with a grain of salt.

"The Sputnik vaccine is an adenovirus vector vaccine, like AstraZeneca and the Johnson & Johnson vaccine, and there's some evidence that these are a little less effective against some of these more seriously mutated variants of concern, like the South African strain and then now Delta," he said.

A recent poll from the mobile app Doctor's Manual found that one-third of Russian doctors still aren't sure about the effectiveness of Russia's COVID-19 shots.

"One of the key aspects to building vaccine confidence is openness and transparency around effectiveness and safety," Head said. "Those attributes are not exactly to the fore in Russia, and perhaps they are suffering from low uptake as a result."

Russian authorities have tried to boost vaccination rates by offering incentives like grocery items or lottery tickets, but the nation still fell short of its goal to vaccinate 30 million people by mid-June.

So as of last week, vaccines are mandatory for certain service workers in Russia, including hairdressers, taxi drivers, and teachers. They can be suspended without pay if they refuse.

"The same approach is being taken a lot of places to try and enforce people to get the vaccines," Hamer said. "But in Russia in particular, there may be some people that will be resistant to that - they don't want to be forced to do things they don't want to do."