Moscow saw a surge in coronavirus cases in June, but it didn’t show up in the official statistics

On July 20, Russian President Vladimir Putin stated that neither voting in the nationwide constitutional plebiscite on July 1, nor the Victory Day parade on June 24, led to any coronavirus outbreaks. Official data from Russia’s public health authority, Rospotrebnadzor, shows that the country’s COVID-19 epidemic is winding down. But official data doesn’t always reflect reality: identifying new cases not only depends on the number of infections, but also on the number of tests conducted and the effectiveness of testing. This means the situation on the ground could be far more complicated. According to Meduza’s calculations, Moscow did see a spike in coronavirus cases during the month of June, it just didn’t show up in the official statistics.

Please note! This translation has been edited and abridged for length and clarity. Also, all Meduza content about the coronavirus pandemic is free to distribute according to Creative Commons CC BY 4.0. You can republish this stuff! (Except for any photographs featured in our stories).

The main point

Following the lifting of quarantine restrictions in June, Moscow’s official statistics showed no trace of a spike in infection rates. But judging by more reliable indicators — namely, looking at mortality rates, rather than the number of registered cases — a new outbreak did take place: it began on June 6, when Moscow Mayor Sergey Sobyanin announced the “beginning of the return to normal life.” The last short peak was around June 22–24 (possibly linked to the Victory Day parade), after that, the rate at which the virus was spreading in the capital began to decline again.

For now, it’s too soon to say whether voting in the nationwide plebiscite affected the incidence of COVID-19 in the capital and across the country; on average, 20–25 days elapse between the time of infection and death registration, so it won’t be possible to reliably judge the number of July 1 cases until the end of this week. That said, one thing is for sure: Russia will see new coronavirus outbreaks against and again. And the fact that the official statistics often don’t capture them is especially dangerous. 

What constitutes an outbreak?

In this case, an “outbreak” refers to a situation when the number of new infections becomes higher than the number of newly recovered patients (or deaths). In epidemiological models, the dynamics of the spread of an infection are set according to the reproduction rate Rt; this rate can be thought of as the average number of people that each infected person passes the virus to before they themselves recover or die. If the reproduction rate is less than one, then the epidemic is winding down, but if it’s more than one then it can be considered a self-sustaining outbreak. 

In Moscow (and in Russia as a whole), the coronavirus reproduction rate dropped below one for the first time in mid-May (after the peak of the first wave). From then on, the epidemic in Moscow slowly died down — according to Meduza’s calculations, the the reproduction rate fell to 0.43 at the end of May, at which point the authorities began to lift restrictions (this rate is much slower than in the hardest hit European countries, as well as in China). On June 6, however, the rate began to go up past one again; the “outbreak’s” peak happened around June 10, when the Rt surpassed 1.2. That said, this value is still much less than at the start of the epidemic, when the number of cases was increasing exponentially and the reproduction rate exceeded 2.5–3. On the other hand, it’s likely that the majority of Russia’s regions never experienced reproduction rates much higher than one. 

Do the official statistics show all of these fluctuations?

No. The data Rospotrebnadzor publishes on the number of infections is gathered in the regions on the basis of testing (this primarily involves people with symptoms and the people they come into contact with). As such, the data is inherently inaccurate — but the same problem exists all over the world. In large part, coronavirus indicators depend not on the real dynamics of an epidemic’s development, but rather on the number of tests conducted and the testing strategy in place. By the looks of things, Russia detected a smaller proportion of coronavirus infections in July 2020 than in May and June. From June 19 to July 19, almost half a million fewer tests were carried out than during the period of May 19 to June 19. If in the spring officials appeared to be deliberately trying to actively identify asymptomatic carriers of the virus, they abandoned this idea in the summer. As such, at least in part, the decline in the number of newly registered coronavirus cases reflects a change in testing policy, rather than an actual waning of the epidemic. 

What are the alternatives to official data?

It’s possible to rely on other more reliable data, such as the figures on coronavirus deaths. The idea is that COVID-19’s actual death rate (the number of deaths relative to the total number of infected people — including those with and without symptoms) varies little in all countries around the world. In fact, it’s almost exactly the same: between 0.5 percent and 0.8 percent (the median is 0.68 percent). In all countries with “older” populations, including very “old” countries like Italy, the death rate is slightly higher, while countries with younger populations — for example, countries in Africa — have slightly lower death rates.

Based on the data on deaths from the virus, it’s possible to calculate the number infections (with a 20–25 day delay). And this is exactly what allows you to identify the outbreak in Moscow during the beginning to middle of June: the period when the quarantine restrictions were lifted. 

Moscow didn’t reintroduce quarantine, so why did the outbreak end?

Last week, Moscow Mayor Sergey Sobyanin stated that the most important thing is “herd immunity” — claiming that in his opinion, 60 percent of people in the Russian capital have already been infected with COVID-19. Where Sobyanin got this figure remains unclear; earlier, municipal officials referred to 20 percent of the population being infected. According to Meduza’s calculations (based on the aforementioned method using mortality rate data), around 1.88 million people in Moscow should have gained immunity to the virus by the end of June — that’s a little less than 15 percent of the city’s population. 

On the one hand, according to epidemiologists, 15 percent of the population gaining immunity could be enough for the epidemic to end on its own — or for the number of cases to stop growing rapidly, at least. However, different segments of the population experience different levels of social interaction. From an epidemiological perspective, the most active people (for example, service workers) likely became infected at the start of the pandemic; the outbreak among these groups appeared to “spread like wildfire” — each coronavirus patient infected two or even three “vulnerable people.” In just a few weeks, more than half of the members of these small, active groups had become infected, meaning herd immunity had been achieved within their circle. 

On the other hand, less active groups (for example, people remaining in isolation) were only slightly affected by the initial outbreak. In all likelihood, the virus began to spread within these other groups after the quarantine restrictions were lifted, but not as quickly as it initially spread among the most active people. As a result, the reproduction rate during the June outbreak barely exceeded one. 

The fact that the first outbreak after the end of quarantine faded away quickly is no guarantee that there won’t be a second major coronavirus wave: it’s fully possible that at a later date, the virus will quickly spread to segments of the population that were less active during quarantine: among the workers of temporarily closed enterprises, students, the elderly, and so on. If the reproduction rate among these previously protected groups is consistently above one, then the epidemic will begin to accelerate again. 

What is the situation like in other regions?

Unlike at the epicenter of Russia’s coronavirus epidemic — Moscow — in the majority of the regions even the most active groups of citizens have yet to fall ill. So they could still experience large-scale outbreaks like the capital saw in the spring. According to models calculating the spread of the coronavirus in the Russian regions, so far only a few areas are facing “growing” epidemics: the city of St. Petersburg, the Sverdlovsk, Orenburg, Volgograd, and Orlov regions, as well as the Altai Territory and Sakhalin.

That said, it’s possible that the official statistics being used to create these models are simply masking outbreaks in a number of regions. 

Update: After Meduza published this article, our editors received a letter from the Moscow Health Department, claiming that our reports about a surge in coronavirus cases in Moscow around June 6 (calculated on the basis of the mortality rate) are not true. “According to data from Moscow’s operational headquarters for the control and monitoring of the coronavirus, from June 6–24 there was a constant decrease in the number of deaths from COVID-19,” the letter said. However, taking into account the aforementioned 20–25 day lag in death registrations, an increase in the number of infections in early June can be seen in the data on increased mortality in late June and early July. This increase can be verified by looking at the graph of official data on coronavirus deaths in Moscow.